Granville-Phillips 307 Series 307 Vacuum Measurement Controller Instruction Manual

Series 307

Granville-Phillips ® Series 307

Vacuum Measurement Controller

Instruction Manual

Instruction manual part number 307024

Revision A - August 2011

2

Series 307



This Instruction Manual is for use with all Granville-Phillips

Series 307 Vacuum Measurement Controllers. A list of applicable catalog numbers is provided on the following page.

Customer Service/Support

For customer service, 24 hours per day, 7 days per week, every day of the year including holidays, toll-free within the USA, phone 1–800–367–4887

For customer service within the USA, 8 AM to 5 PM, weekdays excluding holidays:

• Toll-free, phone:

• Phone:

• FAX:

1–800–776–6543

1–303–652–4400

1–303–652–2844

• Email:

[email protected]

• World Wide Web: www.brooks.com

Instruction Manual

© 2011 Brooks Automation, Inc. All rights reserved.

Granville-Phillips

®

and Convectron

®

are registered trademarks of Brooks Automation, Inc.

All other trademarks and registered trademarks are the properties of their respective owners.

Series 307 Vacuum Gauge Controller Part Numbers

307501: I

2

R degas (Std.) / half-rack mount, remote power supply

307502: I

2

R degas (Std.) / left mount, side-by-side with power supply for 19-inch rack

307507: EB degas (UHV) / half-rack mount, remote power supply

307508: EB degas (UHV) / left mount, side-by-side with power supply for 19-inch rack

307601: I

2

R degas (Std.) / clean room, half-rack mount, remote power supply

307602: I

2

R degas (Std.) / clean room, left mount, side-by-side with power supply for 19-inch rack

307701: I

2

R degas (Std.) / half-rack mount, remote power supply

307702: I

2

R degas (Std.) / side-by-side with power supply for 19-inch rack

307703: EB degas (Std.) / Red display (Ion Gauge Only), side-by-side with power supply for 19-inch rack

307704: I

2

R degas (Std.) / Red display (Ion Gauge Only), side-by-side with power supply for 19-inch rack

307 X X X - X X X - X X

Interface Options (Slot X):

None

RS-232

RS-485

IEEE 488

Linear Analog Output

Gauge Options (Slot Y):

None

Dual Convectron

Convectrom / Capaitance Manometer

Dual Thermocouple

Setpoint Options (Slot Z):

None

2 setpoint relays for ion gauge

6 setpoint relays, 2 per channel

6 setpoint relays, user configurable

Display Options - Measurement Units:

Torr mbar

Pa

Power Cord Options:

North America 115 V

North America 240 V

Universal Europe 220 V

United Kingdom 240 V

3

4

1

2

T

M

P

0

A

B

C

2

3

0

1

0

A

B

C

D

Table of Contents

Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Service Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Extended Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

FCC Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Chapter 1

The Series 307 Vacuum Gauge Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.1

General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2

Available Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2.1 Power Supply Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2.2 Ion Gauge (IG) Electrometer Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2.3 Remote Input/Output Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2.4 Convectron Gauge (CG) Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

1.2.5 Thermocouple Gauge (TC) Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.6 Process Control Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.7 RS-232 Computer Interface Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.8 RS-485 Computer Interface Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.9 IEEE-488 Computer Interface Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.2.10 Capacitance Manometer Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.3

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.3.1 Line Voltage Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.3.2 Module Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

1.3.2.1 Remote Input/Output Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

1.3.2.2 Single Digit Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

1.3.3 Mounting Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

1.3.4 Ionization Gauge Types and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

1.3.5 Cable Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1.3.6 System Ground Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1.3.6.1 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1.3.7 Grounding the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

1.4

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1.4.1 Summary of Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1.4.2 Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1.4.3 Ion Gauge On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

1.4.4 Degas On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.4.5 Remote Input/Output Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

1.5

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1.5.1 Ion Gauge Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

1.5.2 Microcontrollers and Bus Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

1.6

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

1.7

Troubleshooting, Basic 307 Vacuum Gauge Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.7.1 Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.7.2 Fault Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

1.7.3 Repair Ordering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1.8

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

1.9

307 Extended Capability Vacuum Gauge Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.9.1 Gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.9.2 Process Control (C, D and E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1.9.3 Computer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Chapter 2

The Ion Gauge Electrometer Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.2

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.2.1 Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.3

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Series 307 Vacuum Gauge Controller

Instruction Manual - 307024 - Rev. A

5

Table of Contents

6

2.3.1 Ion Gauge On/Off and Degas On/Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

2.3.2 Relative Gas Sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

2.4

Electrometer Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

2.5

Electrometer Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2.6

Electrometer Module Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Chapter 3

The Convectron Gauge Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.1

Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.1.1 Explosive Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.1.2 Limitation on Use of Compression Mounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.1.3 Tube Mounting Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.1.4 Overpressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.1.5 High Indicated Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.1.6 Chemical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.1.7 Sensor Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.1.8 Tube Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.2

Convectron Module, Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.3

Convectron Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.3.1 Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3.3.2 Convectron Gauge Tube Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

3.3.2.1 Important Precautions for Gauge Tube Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

3.3.3 Gauge Tube Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

3.3.3.1 Compression Mount (Quick Connect) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

3.3.3.2 1/8 NPT Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.3.3.3 NW16KF Flange Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.4

Convectron Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.4.1 Reading Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.4.2 Special Considerations for Use Below 10

-3

Torr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

3.4.3 Use With Gases Other Than N

2

and Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.4.4 Indicated vs. True Pressure Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.4.5 Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

3.5

Convectron Calibration and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3.5.1 Cleaning the Gauge Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

3.6

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

3.7

Convectron Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3.7.1 Transducer Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3.8

Convectron Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Chapter 4

The Thermocouple Gauge Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

4.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

4.2

Thermocouple Gauge Module Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

4.2.1 Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

4.2.2 Thermocouple Gauge Tube Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.3

Thermocouple Gauge Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.3.1 Reading Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.3.2 Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.3.3 Filament Auto Turn-On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

4.4

Thermocouple Gauge Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

4.5

Thermocouple Gauge Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

4.6

Thermocouple Gauge Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Chapter 5

The Process Control Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5.1

Introduction to the Process Control Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5.2

Process Control Module Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5.2.1 Process Control System Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

5.3

Process Control Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

5.3.1 Setpoint Display and Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

5.3.2 Points to Consider in Using the Process Control Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

5.3.3 Relay Polarity Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74



Table of Contents

5.3.4 Ion Gauge Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

5.4

Process Control with User Assignable Gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

5.5

Process Control Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

5.6

Process Control Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

5.7

Process Control Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 6

The RS-232 Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.2

RS-232 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.2.1 Selecting the Byte Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.2.1.1 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.2.1.2 Character Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.2.1.3 Talk-Only Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.2.1.4 Handshake Line Control Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.2.1.5 Invert RTS Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.3

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.3.1 Command Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.3.2 Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.4

RS-232 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

6.4.1 Handshaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

6.5

RS-232 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.6

RS-232 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Chapter 7

The RS-485 Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.1

RS-485 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.2

RS-485 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.2.1 RS-485 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

7.2.2 Response Delay for the RS-485 Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.2.3 Selecting the Byte Format for RS-485 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.2.4 Character Framing for the RS-485 Computer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

7.2.5 Connecting the RS-485 Computer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

7.3

Preparing for use of the RS-485 Computer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

7.4

RS-485 Command Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

7.5

RS-485 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Chapter 8

The IEEE 488 Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.2

IEEE 488 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.2.1 Selecting the Interface Bus Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

8.2.2 Talk-only Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.2.3 SRQ Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.3

IEEE 488 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.3.1 Command Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

8.3.2 Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

8.4

IEEE-488 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

8.5

IEEE 488 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Chapter 9

The Convectron/Capacitance Manometer Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101

9.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

9.2

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

9.2.1 Units of Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

9.2.2 Capacitance Manometer Cable Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

9.3

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9.3.1 Reading Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9.3.2 Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

9.4

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9.4.1 Initial Transducer Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

9.5

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

9.6

Capacitance Manometer Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105



7

Table of Contents

9.7

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Chapter 10

Linear Analog Output Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107

10.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

10.2

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

10.2.1 Electrometer (IG) Range Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

10.2.2 Cable Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

10.2.3 Pin Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

10.3

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

10.4

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.4.1 IG Zero Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.4.2 IG Full Scale Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.4.3 TC Zero Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.4.4 TC Full Scale Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.5

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

10.6

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

10.7

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

10.7.1 Thermocouple Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

10.7.2 Electrometer (IG) Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Cable Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119

8



Safety Instructions

START BY READING THESE IMPORTANT SAFETY INSTRUCTIONS AND NOTES collected here for your convenience and repeated with additional information at appropriate points in these instructions.

These safety alert symbols mean caution - personal safety, property damage or danger from electric shock. Read these instructions carefully.

In these instructions the word “product” refers to the Granville-Phillips Series 307 Vacuum Gauge

Controller and all of its approved parts and accessories.

NOTE: These instructions do not and cannot provide for every contingency that may arise in connection with the installation, operation, or maintenance of this product. If you require further assistance, contact Granville-Phillips at the address on the title page of this manual.

This product has been designed and tested to offer reasonably safe service provided it is installed, operated, and serviced in strict accordance with these safety instructions.

These safety precautions must be observed during all phases of operation, installation, and service of this product. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the instrument.

Brooks Automation, Inc./Granville-Phillips disclaims all liability for the customer's failure to comply with these requirements.

The service and repair information in this manual is for the use of

Qualified Service Personnel. To avoid shock, do not perform any procedures in this manual or perform any servicing on this product unless you are qualified to do so.

•

Read Instructions – Read all safety and operating instructions before operating the product.

•

Retain Instructions – Retain the Safety and Operating Instructions for future reference.

•

Heed Warnings – Adhere to all warnings on the product and in the operating instructions.

•

Follow Instructions – Follow all operating and maintenance instructions.

•

Accessories – Do not use accessories not recommended in this manual as they may be hazardous.

To reduce the risk of fire or electric shock, do not expose this product to rain or moisture.

All conductors in, on, or around the vacuum system that are exposed to potential high voltage electrical discharges must either be shielded at all times to protect personnel or must be connected to earth ground at all times.

Replacement Parts - When replacement parts are required, be certain to use the replacement parts that are specified by Granville-Phillips or that have the same characteristics as the original parts. Unauthorized substitutions may result in fire, electric shock or other hazards.



9

Safety Instructions

Safety Check - Upon completion of any service or repairs to this product, ask the Qualified Service Person to perform safety checks to determine that the product is in safe operating order.

Finite Lifetime - After ten years of normal use or even non-use, the electrical insulation in this product may become less effective at preventing electrical shock. Under certain environmental conditions which are beyond the manufacturer’s control, some insulation material may deteriorate sooner. Therefore, periodically inspect all electrical insulation for cracks, crazing, or other signs of deterioration. Do not use if the electrical insulation has become unsafe.

Danger, High Voltage – The high voltages present within the Power Supply are capable of causing injury or death. To avoid electric shock, wait 3 minutes after power is removed before touching any component within the

Power Supply. This will permit charged capacitors to discharge.

Be aware that an electrical discharge through a gas may couple dangerous high voltage directly to an ungrounded conductor almost as effectively as would a copper wire connection. A person may be seriously injured or even killed by merely touching an exposed ungrounded conductor at high potential.

This hazard is not unique to this product.

Install suitable devices that will limit the pressure to the level that the vacuum system can safely withstand. In addition, install suitable pressure relief valves or rupture disks that will release pressure at a level considerably below the pressure that the system can safely withstand.

Suppliers of pressure relief valves and pressure relief disks are listed in the Thomas Register under

“Valves, Relief”, and “Discs, Rupture”.

Confirm that these safety devices are properly installed before installing the product. In addition, check that (1) the proper gas cylinders are installed, (2) gas cylinder valve positions are correct on manual systems, and (3) the automation is correct on automated gas delivery systems.

Proper Grounding:

All components of a vacuum system used with this or any similar high voltage product must be maintained at earth ground for safe operation.

The power cord of this product shall be connected only to a properly grounded outlet. Be aware, however, that grounding this product does not guarantee that other components of the vacuum system are maintained at earth ground.

Complying with the usual warning to connect the power cable only to a properly grounded outlet is necessary but not sufficient for safe operation of a vacuum system with this or any similar high voltage producing product.

Verify that the vacuum port to which the gauges are mounted is electrically grounded. It is essential for personnel safety as well as proper operation that the envelope of the gauge be connected to a facility ground. Use a ground lug on a flange bolt if necessary.

10




Vacuum gauges with compression fittings may be forcefully ejected if the vacuum system is pressurized.

Using the N

2

calibration to pressurize a vacuum system above about

1 Torr with certain other gases can cause dangerously high pressures

which may cause explosion of the system. See Section 3.4 on page 3-50

before using with other gases.

Warning - If used improperly, Convectron Gauges can supply misleading pressure indications that can result in dangerous overpressure conditions within the system. For use with gases other than air or N

2

, consult the gas

type correction charts in Section 3.4 on page 3-50.

Do not operate in an explosive atmosphere.

Do not operate the product in the presence of flammable gases or fumes.

Operation of any electrical instrument in such an environment constitutes a definite safety hazard.

Do not use the product to measure the pressure of explosive or combustible gases or gas mixtures. The sensor wire of the Convectron

Gauge normally operates at only 125 °C, but it is possible that Controller malfunction can raise the sensor temperature above the ignition temperature of combustible mixtures.

Danger of explosion or inadvertent venting to atmosphere exists on all vacuum systems which incorporate gas sources or involve processes capable of pressurizing the system above safe limits.

It is the installer's responsibility to ensure that the automatic signals provided by the product are always used in a safe manner. Carefully check manual operation of the system and the set point programming before switching to automatic operation.

Where an equipment malfunction could cause a hazardous situation, always provide for fail-safe operation. As an example, in an automatic backfill operation where a malfunction might cause high internal pressures, provide an appropriate pressure relief device.

The fumes from solvents such as trichloroethylene, perchloroethylene, toluene, and acetone can be dangerous to health if inhaled. Use only in well ventilated areas exhausted to the outdoors. Acetone and toluene are highly flammable and should not be used near an open flame or energized electrical equipment.

11




Service Guidelines

Some minor problems are readily corrected on site. If the product requires service, please contact our Customer Service Department at 303-652-4400 for troubleshooting help over the phone.

If a product must be returned to the factory for service, request a Return Material Authorization

(RMA) from Brooks Automation / Granville-Phillips. Do not return products without first obtaining an RMA.

For vacuum gauges, a hazardous materials document may be required. The Brooks Automation /

Granville-Phillips Customer Service Representative will advise you regarding the required hazardous materials document and procedures.

When returning equipment to Brooks Automation / Granville-Phillips, be sure to package the products to prevent shipping damage. Circuit boards and modules separated from the Series

307Controller chassis must be handled using proper anti-static protection methods and must be packaged in anti-static packaging. Brooks Automation / Granville-Phillips will supply return packaging materials at no charge upon request. Shipping damage on returned products as a result of inadequate packaging is the Buyer's responsibility. Before you return products to the factory, obtain

an RMA number by contacting Granville-Phillips customer service:

•

Phone 1-303-652-4400 or 1-800-776-6543 within the USA, 8 AM to 5 PM Mountain Time

Zone, weekdays excluding holidays.

•

Phone 1-800-367-4887 within the USA, 24 hours per day, seven days per week.

•

Email [email protected]

•

For Global Customer Support, go to www.brooks.com

, click on Contact Us, then click on

Global Offices to locate the Brooks Automation office nearest you.

.

Damage Requiring Service

Disconnect the product from the wall outlet and all power sources and refer servicing to Qualified

Service Personnel under the following conditions:

a.

b.

c.

d.

e.

When any cable or plug is damaged.

If any liquid has been spilled onto, or objects have fallen into the product, or if the product has been exposed to rain or water.

If the product does not operate normally even if you follow the operating instructions.

Adjust only those controls that are covered by the operation instructions. Improper adjustment of other controls may result in damage and will often require extensive work by a qualified technician to restore the product to its normal operation.

If the product has been dropped or the enclosure has been damaged.

When the product exhibits a distinct change in performance. This indicates a need for service.

Replacement Parts − When replacement parts are required, be certain to use the replacement parts that are specified by Brooks Automation/Granville−Phillips, or that have the same characteristics as the original parts. Unauthorized substitutions may result in fire, electric shock or other hazards.

Safety Check − Upon completion of any service or repairs to this product, ask the

Qualified Service Person to perform safety checks to assure that the product is in safe operating order.

12




Extended Warranty

Brooks Automation, Inc./Granville-Phillips provides an extended warranty period to five (5) years from the date of shipment for the Granville-Phillips Series 307 Controllers. The Brooks Automation,

Inc. General Terms and Conditions of Sale provide the complete and exclusive warranty for Brooks

Automation, Inc./Granville-Phillips products. This document is located on our web site at www.brooks.com, or may be obtained by contacting a Brooks Automation, Inc./Granville-Phillips

Customer Service Representative.

Certification

Brooks Automation, Inc./Granville-Phillips certifies that this product met its published specifications at the time of shipment from the factory. Brooks Automation, Inc./Granville-Phillips further certifies that its calibration measurements are traceable to the National Institute of Standards and

Technology to the extent allowed by the Institute's calibration facility.

FCC Verification

NOTE: This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with this instruction manual, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.

If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

•

Reorient or relocate the receiving antenna.

•

Increase the separation between the equipment and the receiver.

•

Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

•

Consult the dealer or an experienced radio or television technician for help.

13




14



Chapter 1

1

The Series 307 Vacuum Gauge Controller

1.1 General Description

The 307 Vacuum Gauge Controller (VGC) measures pressures from 5 x 10

-12 or 6.6 x 10

-10

Torr (6.6 x 10

Pa) to atmosphere, depending on the modules and transducers used.

-12

mbar

The 307 VGC can operate two ion gauges (IG) sequentially, along with two Convectron gauges

(CG), two thermocouple gauges (TC) simultaneously, or one capacitance manometer and one

Convectron gauge.

Pressure readout is via three front panel displays, analog output, and available computer interface.

The 307 VGC is a modular instrument which can be easily customized to fit most user's exact needs. Infrequently used controls are housed behind a hinged front panel, reducing front panel clutter and allowing the control unit to reside in a half-rack space.

The power supply is housed in a separate enclosure and may be rack-mounted alongside the control unit, or mounted separately. Reliability is increased by removing power dissipation from the control unit enclosure, which needs no ventilation. Remote mounting of the power supply minimizes heat generated in the user's instrument rack and thus increases reliability of components.

1.2 Available Configurations

1.2.1 Power Supply Module

Choice of one or two ion gauges, available with electron bombardment degas or resistance heating degas. Line voltage ranges are 90-130 volts ac or 180-260 volts ac.

1.2.2 Ion Gauge (IG) Electrometer Module

Standard IG Electrometer Module: IG pressure readout from 1 x10

-10

Torr (readable to 10

-11

Torr) to

1 x 10

-1

Torr, depending on IG type and emission current used. The module reads either of two gauges sequentially. Adjustments for gauge sensitivity and emission current affect both tubes.

Analog recorder output is also provided.

Ultra-high Vacuum IG Electrometer Module: Extends lower pressure limit to 5 x 10

-12

Torr, and allows separate sensitivity and emission level adjustments for each ion gauge. Degas power is adjustable when used with the electron bombardment degas power supply.

1.2.3 Remote Input/Output Module

Provides IG status outputs, remote filament on/off, degas on/off, front panel lockout capability, and fault or degas status indication relay.

1.2.4 Convectron Gauge (CG) Module

Permits pressure measurements from 1 x 10

-4

to 990 Torr (N

2

equivalent) from two

Granville-Phillips Series 275 Convectron Gauges simultaneously. Two channel (A/B) modules allow for automatic turn-on and shut-off of ion gauges based on Convectron pressure. Also provides analog output of each indicated pressure.



15

1


1.2.5 Thermocouple Gauge (TC) Module

Provides the same functions as the Convectron module, but pressure measurement range is

1 x 10

-3

Torr to 1 Torr.

1.2.6 Process Control Module

Provides 2 or 6 single pole, double throw relays: Two channels are associated with each display line. Digital setpoints have switch-setable polarity for relay activation above or below the setpoint, or if purchased, user selectable gauge setting. Manual override switches are built-in.

1.2.7 RS-232 Computer Interface Module

Provides readout of pressure and process control relay status, and ion gauge control.

1.2.8 RS-485 Computer Interface Module


1.2.9 IEEE-488 Computer Interface Module


1.2.10 Capacitance Manometer Module

Provides gas-type independent pressure measurement from 1 x 10

-4

to 999 Torr depending on the manometer head being used. Allows local range, zero and full scale adjustments and provides power to the transducer. Readout for one Convectron gauge with features as described in the

Convectron gauge section of this instruction manual is included along with analog outputs for both gauges.

16



1


1.3 Installation

1.3.1 Line Voltage Selection

Line voltages of 90-130 or 180-260 Vac are user selectable via jumpers internal to the power

supply. Compare your unit to Figure 1-1 to determine if it is configured for your requirements. Do

not apply power until the correct configuration is achieved.

Figure 1-1

Line Voltage Select Jumpers, Power Supply PC Board.

1.3.2 Module Installation

Only a Phillips screwdriver is necessary for module installation.

Since the 307 modules contain static sensitive devices, follow the anti-static procedures outlined in

Section 1.7 on page 31 when handling printed circuit boards.

The modules for the 307 VGC have metal brackets which interlock to form the front and rear sections of the chassis. Modules must be installed in their proper positions within the chassis (see

Figure 1-2 on page 18).



17

1


18

Figure 1-2

Module Positions.

1 —

Position for Computer Interface Module

2 —

Blank Module

3 —

Position for IG Electrometer Module

4

5

—

Position for Convectron, Thermocouple or Capacitance Manometer Gauge

Module

—

Position for Process Control Module

To install a module:

1.

2.

3.

Turn off the power and remove all cabling from rear panel.

Remove the top cover of the control unit by removing the upper front screw and the rear screw on each side. It is not necessary to remove the lower front screws.

Remove the connectors holding the bus ribbon cable from all boards to the right (when viewed from the front) of the position in which the new module is to be installed, or remove the display panel and all connectors to the left.

4.

5.

6.

7.

Remove the blank filler module in the position in which the board is to be installed.

Install the new module in its proper position. Position all modules so that the chassis segments interlock properly.

Re-connect the bus ribbon cable connectors.

Install the top cover, making sure the door hinge pin is correctly located.



1


1.3.2.1 Remote Input/Output Module

The Remote Input/Output Module

(Figure 1-3) is a small printed circuit

board assembly,

7

, which attaches within the right-rear section of the control unit. Mechanical attachment to the rear panel is via the two jackposts

6

, which fasten the connector to the panel in the same manner as the connector on the larger board is fastened. Electrical connection is via a short ribbon cable

8

, terminated with a 14-pin dual-in-line plug. The components of the two printed circuit boards should end up facing each other.

Figure 1-3

Remote Input/Output Option.

1.3.2.2 Single Digit Display

It is possible to blank the second digit in one or more lines of the display by cutting jumpers on the display printed circuit board. The second digit is retained internally, is used by the process control logic, and will be output via the computer interface. The decimal point will still be displayed even though the second digit is blanked. To disable the second digit:

1.

2.

3.

4.

5.

Remove power from the control unit.

Open the hinged door. On the back of the door is a metal plate labeled with operating instructions. This plate is held in place by plastic retainers which may be flexed out of position allowing removal of the plate.

With the plate removed you will see the display printed circuit board (Figure 1-4). Locate

9

, jumpers J1, J2, and J3.

Cut the jumper for the display line(s) for which you wish to disable the second digit; J1,J2, and

J3 for the first, second, and third lines respectively.

Snap the backplate back into its retainers.

Figure 1-4

Display Printed Circuit Board.



19

1


1.3.3 Mounting Configurations

Figure 1-5 on page 21 illustrates the various configurations available for mounting the 307 control

unit and power supply.

Note that when installing a mounting ear be open.

10

into the left side of the control unit, the door should

The bracket

13

used to connect two control units for side by side rack mounting is not symmetrical. Install as shown.

The rear support bracket assembly consists of a U-shaped bracket power supply, and spring clamps

11

12

which bolts directly to the

which grip into grooves in the side of the control unit. When purchased separately the assembly is provided with two clamps. Remove one or both as necessary when attaching to power supply enclosures rather than control units.

For configurations other than rack mounting, four brackets power supply.

14

are provided for attachment to the

20



1


Figure 1-5

Mounting Methods.



21

1


1.3.4 Ionization Gauge Types and Installation

WARNING - Do not attach cables to glass gauge pins while the gauge is under vacuum. Accidental bending of the pins may cause the glass to break and implode. Cables once installed should be secured to the system to provide strain relief for the gauge tube pins.

WARNING - Ionization gauges are safe for use only if all exposed conductors on the gauge and on controller and on vacuum system are grounded.

Verify that the vacuum port to which the Ion Gauge is mounted is electrically grounded. It is essential for personnel safety as well as proper operation that the envelope of the gauge be connected to a facility ground. Use a ground lug on a flange bolt if necessary.

The 307 VGC is designed to operate 1 or 2 Bayard-Alpert type or equivalent ionization gauges.

Coated Iridium filament type gauges are recommended if the filament auto-on feature is to be used.

At higher pressures iridium filaments provide longer operating life and greater burnout resistance.

When installing your ion gauge, note that if placed near the pump, the pressure in the gauge may be considerably lower than in the rest of the system. If placed near a gas inlet or source of contamination, the pressure in the gauge may be higher.

If an unshielded gauge is placed near an electron beam evaporation source or used in a sputtering system, spurious electrons or ions may disturb the measurement. Screens or other shielding should be placed between the gauge and the system if spurious charged particles or severe electromagnetic interference is present. Consideration should also be given to electrostatic shielding of glass tubulated gauges when measuring pressures near their x-ray limits.

Granville-Phillips offers 3 cable types for ion gauges. One has a standard connector for the series

274 tubulated gauge tubes. One has individual pin sockets for use with non-standard pin configurations as well as with Granville-Phillips “nude” tubes. The third is for use with the Varian

564 wide range tube.

Figure 1-6 shows typical tube base configurations used with the standard connector cable. See for

detailed cable diagrams.

22

Figure 1-6

Standard Tube Base Configurations.



1


When connecting an individual pin socket type IG cable to an IG tube where electron beam degas will be employed using only one grid connection, the red socket lead should be used, not the brown one.

1.3.5 Cable Connections

The 307 VGC power supply is housed separately from the control unit, and feeds power to it via the

supplied interconnecting cable. See Figure 1-7 for cable connections. Tighten screws to secure

connectors.

Figure 1-7

307 VGC Cable Connections.

The collector cable should be routed along the control cables for best noise immunity. See Figure

1-8.

Figure 1-8

Collector Cable Routing.



23

1


1.3.6 System Ground Test Procedure

(Refer to the Safety Instructions Proper Grounding: on page 10 for further information)

1.3.6.1 Procedure

Physically examine the grounding of both the 307 power supply and the vacuum chamber. Is there an intentional heavy duty ground connection to all exposed conductors on the vacuum chamber?

There should be. Note that a horizontal “O” ring or “L” ring gasket, without metal clamps, can leave the chamber above it electrically isolated. Power can be delivered to mechanical and diffusion pumps without any ground connections to the system frame or chamber. Water line grounds can be lost by a plastic or rubber tube interconnection. What was once a carefully grounded vacuum system can, by innocent failure to reconnect all ground connections, become a very dangerous device. Use the following procedure to test each of your vacuum systems which incorporates an ionization gauge.

This procedure uses a conventional Volt-Ohm Meter (VOM) and Resistor (10 ohm, 10 watt).

1.

With the gauge controller turned off, test for both dc and ac voltages between the metal parts of the vacuum chamber and the power supply chassis.

2.

If no voltages exist, measure resistance. The resistance should not exceed 2 ohms. Two ohms, or less, implies commonality of these grounds that should prevent the plasma from creating a dangerous voltage between them. This test does not prove that either connection is earth ground, only that they are the same. If more than 2 ohms is indicated, check with your electrician.

3.

4.

If ac or dc voltages exist and are less than 10 volts, shunt the meter with a 10 ohm, 10 watt resistor. Repeat the voltage measurement. With the shunt in place across the meter, if the voltage remains at 83% or more of the unshunted value, commonality of the grounds is implied. Repeat the measurements several times to be sure that the voltage ratio is not changing with time. If

Voltage (shunted)

Voltage (unshunted)

= .83 or more, this should prevent the plasma from creating a dangerous voltage between these grounds. If more than 10 volts exists between grounds, check with your electrician.

If the voltage change in Step 3 is greater than 17% due to the placement of the shunt, it

complicates the measurement. The commonality of the grounds may be satisfactory and the coupling poor, or the commonality could be poor! Your electrician should be asked to check the electrical continuity between these two ground systems. The placement of a second

ground wire (dashed line in Figure 1-9 on page 26) between the vacuum chamber and the

power supply chassis is NOT a safe answer, for large currents could flow through it.

Professional help is recommended.

24



1


1.3.7 Grounding the System

1.

Connect a heavy duty ground wire #12 AWG or larger from the ground lugs on the backs of the Power Supply and the Control Unit to your facility grounding electrode system. This will provide an earth ground for the Power Supply and for the Control Unit in the event either the interconnect cable or power cable are not in place. Do not connect the ground lug to the vacuum system or other component. Connect it directly to the facility grounding system such as a grounded outlet box or a grounded copper water supply pipe. Do not rely on small metal water lines to ground a component. Someone may replace the metal tubing with plastic tubing thus unwittingly causing a potentially dangerous situation.

2.

3.

Provide a connection to ground for other instruments with electrodes in the vacuum system possibly exposed to high voltage electrical discharges.

Provide a connection to ground for each ungrounded metal component in, on or around the vacuum system, including the gauge envelopes, which personnel may touch and which can potentially be exposed to high voltage electrical discharges within the vacuum system. For example, a metal bell jar resting on an organic O-ring must be connected to ground if an ionization gauge is to be used or if other high voltage sources are present in the vacuum system.

Compliance with the usual warning to connect the power cable only to a properly grounded outlet is necessary but not sufficient for safe operation of a vacuum system with this or any similar high voltage producing product.

Grounding this product does not and cannot guarantee that other components of the vacuum system are all maintained at earth ground.

All conductors in, on, or around the vacuum system that are exposed to potential high voltage electrical discharges must either be shielded at all times to protect personnel or must be connected to earth ground at all times.

After each maintenance/service procedure and before operating the controller and vacuum system make sure that your vacuum system and controller are grounded as shown in the following schematic diagram.

FAILURE TO DO SO COULD BE FATAL.

25



1


26

Figure 1-9

Correct System Grounding.

Be aware that an electrical discharge through a gas may couple dangerous high voltage directly to an ungrounded conductor almost as effectively as would a copper wire connection. A person may be seriously injured or even killed by merely touching an exposed ungrounded conductor at high potential.

This hazard is not unique to this product.



1


1.4 Operation

1.4.1 Summary of Controls and Indicators

A description of the controls and indicators found on a basic 307 VGC is given in this section. For detailed instructions pertaining to particular modules, please consult the chapter for that module.

Figure 1-10

307 VGC Control Unit Front Panel.

1.4.2 Units of Measure

The units of measure displayed is selectable via switches on the electrometer, Convectron, and thermocouple modules. These units will be indicated on the front panel label when shipped from the factory. See the chapters for the specific module for instructions on changing units. The pressure units label

18

is part of the process control channel label and can be changed by the user if the system of units is changed. Slide the label out from the top.

WARNING - Since display units are set separately on the electrometer and

Convectron or thermocouple gauge modules, adjustments must be made to both modules to avoid confusion. Be certain to update the label to reflect any change of units.

16 —

Power On/Off Toggle Key

1.4.3 Ion Gauge On/Off

Ion gauges may be turned on or off in four ways: front panel keys,

15

, remote control, auto-on function of Convectron or thermocouple gauge module, or via the RS-232, RS-485, or IEEE 488 computer interfaces. Two ion gauges can be operated sequentially and not simultaneously.

For use of the available Remote Input/Output option, see below. For use of the IG auto-on function of the Convectron or thermocouple gauge modules, see the instruction manual sections for those modules.

To turn on IG1 from the front panel, press the IG1 on/off button. To turn it off, press again. Note that if you attempt to turn on IG2 while IG1 is already on, IG1 will turn off automatically (and vice versa).



27

1


1.4.4 Degas On/Off

Degas may be turned on/off by either the front panel key,

17

, the available remote input (see below), or the RS-232, RS-485, or IEEE 488 computer interface modules. To turn degas on, press the degas on/off key. To turn it off, press again.

Degas can not be activated unless the IG pressure is below 5 x 10

-5

in torr/mbar units, or 6.6 x 10

-3 in pascal units. Degassing a gauge above this pressure is of little value and may cause sudden pressure bursts that can damage the gauge and create plasma which couples grid voltages to the vacuum system hardware.

1.4.5 Remote Input/Output Option

Five inputs are provided through the rear panel allowing control of the ion gauges, degas, and

lock-out of front panel keys (see Figure 1-11 on page 29). The function of the front panel keys is

reproduced by either a contact closure or an active low logic state on these inputs. For DEGAS

REMOTE and IG REMOTE inputs this low state must be held continuously for at least 25 milliseconds. After this, the input must be allowed to float high for at least 105 milliseconds before another low will be accepted. Front panel keys, other than the power key, will not function if the

KEY DISABLE input is held continuously low. If IG LOCKOUT (asserted low) is pulled to a low voltage level and maintained low, the IG's cannot be turned on either from the front panel or through the computer interface. If the IG is on it will turn off when IG lockout is asserted.

Three single-pole, double-throw relays are provided: Two filament status relays (normally open =

filament off), and status of the FAULT line (normally open = FAULT indication). See Section 1.7.2 on page 32 for a summary of possible sources of the FAULT indication. The FAULT line can be

configured to output DEGAS status by changing the location of JP1 on the remote I/O option board.

Table 1-1

Pin Assignments.

Pin No. Function

1 Key Disable*

6

7

8

4

5

2

3

Degas Remote*

Fault N.C.

Fault N.O.

Fault Com.

IG2 N.C.

IG2 N.O.

IG2 Com.

Pin No. Function

9 IG1 Remote*

10

11

12

13

14

15

IG2 Remote*

IG lockout*

Ground

IG1 Com.

IG1 N.O.

IG1 N.C

* Asserted low inputs

28



1


Figure 1-11

Remote Control Connector.

1.5 Theory of Operation

1.5.1 Ion Gauge Theory

The functional parts of a typical ionization gauge are the filament (cathode), grid (anode) and ion

collector, shown schematically in Figure 1-12. These electrodes are maintained by the gauge

controller at +30, +180, and 0 Vdc, relative to ground, respectively.

The filament is heated by direct current to such a temperature that electrons are emitted, and accelerated toward the grid by the potential difference between the grid and filament. All the electrons eventually collide with the grid, but many first traverse the region inside the grid one or more times.

Figure 1-12

Ion Gauge Schematic.

When an energetic electron collides with a gas molecule, an electron may be dislodged from the molecule, leaving it with a positive charge. Most ions are then accelerated to the collector. The rate at which electron collisions with molecules occur is proportional to the density of gas molecules, and hence the ion current is proportional to the gas density (or pressure, at constant temperature).

The amount of ion current for a given emission current and pressure depends on the ion gauge design. This gives rise to the definition of ion gauge “sensitivity”, frequently denoted by “K”:

K = ion current / (emission current x pressure)

Bayard-Alpert type gauges typically have sensitivities of 10/Torr when used with nitrogen or

atmosphere. Sensitivities for other gases are given in Section 2.3 on page 38.

The ion gauge controller varies the heating current to the filament to maintain a constant electron emission, and measures the ion current to the collector. The pressure is then calculated from these data.



29

1


Ion gauge degas is accomplished by either electron bombardment (EB) or resistance heating (I

2

R) depending on which, if either, you have selected.

During EB degas, the grid voltage is raised to 500 volts and the electron current is increased. The electrons acquire a high energy when accelerated through this potential difference and strike the grid, heating it to a temperature sufficient to free it of contamination.

During I

2

R degas, a large current is passed through the grid structure, raising its temperature and driving off contaminants. Note that some ion gauge designs don't allow I

2

R degas.

In either case, pressure measurement is possible during degas, but large fluctuations may be seen as contaminants are driven off the IG components.

1.5.2 Microcontrollers and Bus Structure

Each module in the 307 has a dedicated microcontroller with internal ROM, RAM, timing, and interrupt management functions. This architecture provides high-performance at low cost with greater reliability and noise immunity than more complicated microprocessor systems using external buses and memory hardware.

Each microcontroller is equipped with a watchdog timer, which automatically generates a reset if the processor fails to fulfill timing “checkpoints” within its code.

Inter-processor communication is accomplished via the display bus. These lines carry BCD-format pressure data which is used to generate the 307 display. The bus is updated once per millisecond.

Out of every sixteen cycles, fifteen cycles are used for display data, and one is reserved for inter-processor communication. Modules that require pressure data, such as process control and computer interface, take it directly from the display update cycles.

1.6 Calibration

Calibration instructions for each module, where relevant, may be found in the chapters for individual modules. Adjustments found within the power supply are:

19 —

Filament Current Limit

Do not adjust.

20 —

Grid Bias Potential Adjustment

The grid bias for the ion gauges is factory set to 180 ±10 Vdc, as required by the vast majority of gauges. This can be adjusted via the grid bias potentiometer. The range is approx. 120-220 Vdc.

30

Figure 1-13

Grid Voltage Adjustment,

Power Supply PC Board.



1


1.7 Troubleshooting, Basic 307 Vacuum Gauge Controller

1.7.1 Guidelines

Further troubleshooting information is located in the chapters for specific modules.

The 307 VGC has been designed for easy repair by replacement of modules.

If the user elects to perform repairs at the component level, repairs properly made with equivalent electronic parts and rosin core solder do not represent a violation of the warranty.

Some minor difficulties are user-correctable, and the built-in diagnostic aids described here may be helpful.

Each module has status LEDs which will aid in localizing failures. These are described in the

troubleshooting section of the chapters for each module. Shown in Figure 1-15 on page 33 are

those LEDs found on the 307 VGC control board. This is the PC board on the right side (when viewed from the front) of the 307 control unit, which attaches to the front panel keys via a short ribbon connector.

Since the 307 VGC contains static-sensitive electronic parts, the following precautions must be followed when troubleshooting:

a.

Use a grounded, conductive work surface.

b.

c.

d.

Use conductive envelopes to store or ship MOS devices or printed circuit boards.

Do not operate the 307 VGC with MOS devices removed from the unit.

Do not handle MOS devices more than absolutely necessary, and only when wearing a ground strap.

e.

f.

Do not use an ohmmeter for troubleshooting. Rely on voltage measurements.

Use grounded-type soldering irons only.

Danger, High Voltage

High voltages are present within the power supply, capable of causing injury or death. Do not touch cable connections or inside of the power supply when power is applied.

31



1


1.7.2 Fault Indications

When supplied with the Remote Control Module, the 307 VGC is also equipped with a “fault” relay

(see Figure 1-11 on page 29). The relay is energized when no fault conditions are detected. It

releases under a number of conditions described in Troubleshooting Guide.

Table 1-2

Troubleshooting Guide, Basic 307 VGC.

Symptom Possible Cause

Unit won't power-up, no response to power switch.

Power fuse

21

blown.

Wrong line voltage selection, see Figure 1-1 on page 17.

Power fuse

21

blows repeatedly.

Wrong fuse rating.

Wrong line voltage selection, see Figure 1-1 on page 17.

Fault relay released.

IG won't come on, or comes on briefly then shuts off.

Degas won't come on.

IG pressure reads extremely low.

IG pressure very noisy.

LED

23

out on control board.

LED out,

24

.

LED out,

25

.

LED out,

26

.

LED out,

27

.

Collector input from IG unplugged.

Watchdog reset occurring on some module (probable circuit failure).

Unplugged Convectron gauge or sensor broken in Convectron gauge.

Convectron gauge zero badly out of calibration.

Checksum failure on process control board. Cycle power and check all setpoints.

Broken filament in IG.

System pressure above overpressure shutoff point.

Badly contaminated IG.

Electrostatic charge buildup on glass wall of IG.

Short between IG electrodes.

Improper IG connector hookup.

Ion gauge is a low-maximum emission gauge and Ie switch is on 10 mA.

System pressure above 5 x 10-5 Torr.

Degas fuse blown,

22

.

IG not turned on.

Badly contaminated IG.

Collector unplugged.

IG badly contaminated.

Bad collector cable.

15 volt power to relays bad.

+12 volt supply bad (power to analog circuitry and RS232).

-12 volt supply bad (power to analog circuitry and RS232).

5 volt power to display LED's bad.

5 volt logic supply bad.

32



1


Figure 1-14

Power Supply Rear Panel.

Figure 1-15

Control Board Top View.

1.7.3 Repair Ordering

Telephone Brooks Automation, Inc./Granville-Phillips to obtain a return authorization prior to returning your unit for repairs.

A repair order should accompany returned equipment even when the equipment is being returned for a warranty repair at no charge. This should include a detailed description of the problem in addition to your name, telephone number and address where we may contact you. Equipment returned for repair should be carefully and strongly packaged to withstand shipping abuse.

Components or printed circuit boards to be returned separately should be protected against static damage by wrapping them in static proof containers or in aluminum foil prior to packaging them for shipment. Address replacement/repair orders and correspondence to the address given on the title page of this manual.

If a replacement module is desired, it is important that you give our Service Department the complete catalog number of the module. This will help ensure that you receive the correct replacement.

NOTE: Under no circumstances will Brooks Automation, Inc./Granville-Phillips be liable for shipping damages due to rough handling, improper packaging, or other circumstances beyond its control.

All return shipments must be freight prepaid.



33

1


1.8 Specifications

See the chapters for each module for additional specifications relating to that module.

Table 1-3

Specifications, Basic 307 Vacuum Gauge Controller

Physical

Control Unit

Width

Height

Depth

Weight

Power Units

Width

Height

Depth

Weight

Electrical

Voltage

Frequency

Power

Fuse Ratings -Line fuse

241 mm (9.5 in.) with 1/2 rack mounting ears

89 mm (3.5 in.)

356 mm (14 in.) includes 76 mm (3 in.) for connectors and cables

3 kg (6.5 lb.)

203 mm (8 in.)

89 mm (3.5 in.)

330 mm (13 in.) includes 89 mm (3.5 in.) for connectors and cables

4 kg (8.5 lb.)

Environmental Operating Temperature

Electronic Accuracy

Display Resolution

Display Update Time

Filament Status Relay Contact Rating

IP Rating

90-130 Vac or 180-260 Vac

50 or 60 Hz

250 watts max.

3 A (90-130 V), 1.5 A (180-260 V), 250 Vac

2 A (90-130 V), 1 A (180-260 V) 250 Vac

0 °C to 40 °C

Typical ±3% of reading at ambient temperature = 25 ± 5 °C

Scientific notation, 2 significant digits

0.5 sec typical

4 A, 250 Vac resistive load or 30 Vdc

IP21

34



1


1.9 307 Extended Capability Vacuum Gauge Controller

In the extended configuration the 307 VGC is a full-rack instrument (with separately mounted power supply) that provides up to 6 displays, 7 transducers, and 12 process control channels. The extra capacity is provided in a second chassis mounted side by side, to the right of the 307 VGC control unit. The power supply is mounted separately.

The second control chassis may be equipped with 3 Convectron (CG) or thermocouple (TC) gauges, and an additional process control board with either 2 or 6 relays. A single-gauge (CG or TC) module drives the fourth display line (the first display line of the second chassis), and a dual-gauge (CG or

TC) module drives the second two displays of the second chassis.

Please refer to chapters 3, 4, 5, 6, 7, 8 and 9 for information on the use of Convectron gauges, thermocouple gauges, 307 process control modules, and computer interfaces, respectively. All the information in these chapters applies to the extended configuration, with the following exceptions:

1.9.1 Gauges

The extended chassis adds additional Convectron or thermocouple gauges only, not additional ion gauges.

The 3 additional gauges in the second chassis cannot be used to automatically turn on the ion gauges.

1.9.2 Process Control (C, D and E)

This additional process control module provides relays in pairs that are associated with each display line. The 3 additional displays are labeled “C”, “D”, and “E”, and are associated with process control channels 1 and 2, 3 and 4, 5 and 6, respectively.

The ion gauge assignment DIP switches on the process control module will be factory set as if to assign channels 1 and 2 to IG1. This does not cause these 2 relays to be activated by IG1, but rather enables these channels to accept data from display line “C” of the extended chassis. These switch settings should not be changed.

1.9.3 Computer Interface

All of the pressure and process control status data from up to 6 displays and 12 process control channels is accessible via a single computer interface module (RS-232 or IEEE 488).

The 307 extended capability computer interface no longer supports the talk-only mode. If this mode is necessary for your application, contact a Granville-Phillips application engineer.

The extended capability computer interface has the same command syntax as the standard 307 interface, with the following additions:

The DS command has additional modifiers CG3, CG4 and CG5 which return the pressure from the 3 gauges in the second expansion chassis.

Example 1 –

Display pressure from display line “D”, the fourth low-vacuum transducer and the fifth display line in the extended configuration:

From computer:

From 307:

DS CG4 CRLF

3.70E-1CRLF indicates this transducer is reading a pressure of 3.7 x 10

-1

.



35

1


The DS command allows as modifiers the numbers 1 through 6 to display the contents of display lines 1 through 6.

Example 2 –

Display pressure from display line “D”, which is the fifth display in the extended configuration:

From computer:

From 307:

DS 5 CRLF

3.70E-1CRLF thus, the modifiers 1-6 perform exactly as the modifiers “IG”, “CG1” through “CG5”, but have been added to provide a simpler command syntax.

A new command PC2S has been added. This command functions in the same way as the PCS command, but refers to the process control channels residing in the second chassis, if installed.

Example 3 –

Assume that channels 1-3 in the second chassis are active, and 4-6 are inactive:

Interrogate the status of the third channel in the second chassis:

From computer:

From 307:

PC2S 3 CRLF

1CRLF return a string giving the status of all 6 channels in the second chassis:

From computer:

From 307:

PC2S CRLF

1,1,1,0,0,0CRLF

36



Chapter 2

2

The Ion Gauge Electrometer Module

2.1 Introduction

This chapter covers both the standard and Ultra-High Vacuum (UHV) electrometers. Information

which applies only to the UHV module will be shown in bold type.

The standard ion gauge (IG) Electrometer Module provides ion gauge pressure readout from

1 x 10

-10

Torr (1.3 x 10

-10

mbar or 1.3 x 10

-8

Pascal) to 1 x 10

-1

Torr, air equivalent, depending on the transducer and emission current used. The control unit sequentially operates 1 or 2 ion gauges, depending on power supply configuration.

Adjustments are provided for gauge sensitivity and emission current. Internal switches allow change to Pascal pressure units, and a user selectable "slow update" feature triggers measurement averaging, resulting in a display update frequency of about once every three seconds. The overpressure shutdown threshold is internally adjustable.

Internal failure-indicator LEDs aid diagnosis of problems by indicating certain out-of-bounds electronic conditions.

The UHV module provides pressure measurement to 5 x 10

-12

Torr. This module also offers independent sensitivity and emission current control for each ion gauge, and adjustable degas power when used with electron-bombardment (EB) degas.



Your unit was shipped from the factory pre-set to display the units of measure, Torr/millibar or Pascal, that you requested.

If you want to change units, proceed as follows:

1.

Shut off power to the control unit.

2.

3.

4.

5.

Remove the top cover. Locate the IG Electrometer

Module.

Locate

28

, the display units control switch.

Set the switch to the desired position, OFF = Torr/mbar units, ON = Pascal units.

Change the units of measure on the Convectron or thermocouple gauge module, if installed.

6.

Slip the label card out of the top of the front panel and apply the appropriate pressure units label.

Selection between Torr and mbar units is done by adjusting the IG tube sensitivity to the appropriate units. For example, a typical Bayard-Alpert tube has a sensitivity of 10/Torr or

7.5/mbar. Thus, for this tube, adjusting the sensitivity to 10 will result in display of pressure in Torr. Adjusting to 7.5 will result in display in mbar.

Figure 2-1

Ion Gauge Electrometer

Module, Top View.

37



2


29 —

Display Update Rate Switch

Setting this switch "ON" enables pressure averaging. The display will update about every 3 seconds rather than the normal 0.5 sec typical period.

2.3 Operation

2.3.1 Ion Gauge On/Off and Degas On/Off

See Section 1.4 Operation on page 27 for instructions on turning ion gauges on and off, and turning

degas on and off.

38

Figure 2-2

Electrometer Module Front Panel.

30

—

Displaying Sensitivity and Emission With the Calibration Switch

This switch is used for displaying gauge sensitivity, emission current, and (when used with EB degas) degas power when these parameters must be checked or adjusted.

This switch is activated by setting either to the left or right. On the UHV module, setting to the left

invokes the function for IG1, and to the right for IG2. The function depends on the state of the ion gauge tube:

If the tube is off, setting the switch displays the tube sensitivity in the top display.

If the tube is on but not degassing, the switch displays emission current in amperes.

If the tube is degassing with electron-bombardment degas, the switch displays degas power in watts.

If the tube is degassing with resistance-degas, the switch displays emission current in amperes.

WARNING - Do not leave the calibration switch set after you are done viewing sensitivity, emission, or EB degas power. There is no indication on the front panel that the display holds data other than pressure.

Since the process control and computer interface modules take their pressure data directly from the display, pressure data is periodically substituted for emission data when the tube is on and emission or EB degas power is being displayed. This results in some flicker in the display.



2


31 —

Emission Range Switch

This switch selects between three emission ranges; 0.1 milliampere, 1.0 milliampere, or 10.0 milliampere. Adjustment within each range is achieved with the emission adjustment pot (see below).

On the UHV module, 2 independent emission range switches are provided, one for each gauge.

In general, higher emissions are used at lower pressures. If, for example, you are using a broad range IG tube and wish to measure to its upper pressure limit, the 0.1 mA range is recommended. If you are measuring very low pressures or have a low-sensitivity IG tube, the 10.0 mA range is better.

In general, lower emissions will increase tube life.

32

NOTE: Changing the emission range by one decade will also change the overpressure shutdown

point by one decade. See Section 2.4 on page 42 for details of the overpressure shutdown

adjustment. Adjustment of emission within a range (see below) will not affect the overpressure shutdown point.

—

Emission Adjustment

This potentiometer provides control of the emission within the decade value selected by the emission range switch. The calibration switch must be set with the IG tube turned on to view emission during adjustment. The span of adjustment is from approximately 10% to 120% of the range value.

On the UHV module, 2 independent potentiometers are provided, one for each IG.

Please note that on some earlier generation IG controllers, the emission current adjustment was used to correct for varying tube sensitivities. This is not appropriate on the 307 controller, as an independent sensitivity adjustment is provided (see below).

33 —

Sensitivity Adjustment

This adjustment is used to match tubes of different sensitivities. The calibration switch 30 must be set with the IG off to view sensitivity during the adjustment.

The control unit is shipped from the factory set for a tube sensitivity of 10/Torr, as is typical for glass tubulated Bayard-Alpert type tubes such as the Granville-Phillips 274. UHV nude gauge tubes such as the 274022, 274023 and Varian UHV-24 typically have a sensitivity of about 25/Torr. If an ionization gauge tube of this type is being used, the sensitivity potentiometer should be adjusted for the proper sensitivity (25/Torr). Otherwise, measurement error will result. The approximate range of the adjustment is 3 to 50/Torr.

2.3.2 Relative Gas Sensitivities

Sensitivity depends on the gas being measured as well as the type of IG tube. Table 2-1 on page

2-40 lists the relative gauge sensitivities for common gases. These values are from NASA Technical

Note TND 5285, "Ionization Gauge Sensitivities as Reported in the Literature", by Robert L.

Summers, Lewis Research Center, National Aeronautics and Space Administration. Refer to this technical note for further definition of these average values and for the gauge sensitivities of other gases.

To adjust the 307 VGC to be direct reading for gases other than air or N2, calculate the sensitivity

Kx for gas type x as follows:

K

X

= (R

X

) (KN

2

)

Where KN

2

is the gauge sensitivity for N

2

and R

X

is found from Table 2-1 on page 40.



39

2


Table 2-1

Relative Gas Sensitivities.

Gas

He

Ne

D

2

H

2

N

2

Air

O

2

Rx

0.18

0.30

0.35

0.46

1.00

1.00

1.01

Gas

H

2

O

NO

Ar

CO

2

Kr

SF6

Xe

Rx

1.12

1.16

1.29

1.42

1.94

2.5

2.87

34 —

Degas Power Adjustment

The UHV module allows adjustment of degas power, when used with EB degas, from approximately 10 watts to 40 watts.

35 —

Analog Output

This voltage output signal is proportional to the common logarithm of pressure. If graphed on “loglinear” axes the output voltage is linear with respect to the log of pressure. The analog output is 1 volt per decade of pressure with 0 volts out at 1.0 x 10

-

12

Torr when the emission current range is set to 10 mA. Note that the emission current range setting

affects the scaling of the analog output (see Figure

2-4 on page 41). When the IG is turned off, the

output will switch to slightly greater than +10 Vdc.

40

Figure 2-3

Electrometer Module Back Panel.



2


The UHV electrometer option (307507-8) switches in a preamplifier as pressure decreases at an ion

(collector) current of 10

-10

A. For example, this corresponds to a pressure of 10

-9

Torr with 10 mA emission current. When this switching occurs, there will be a brief (about 2 s duration) drop in the analog output signal. After the electrometer has settled out, the signal is, again, proportional to the

common logarithm of pressure as shown by the UHV ONLY area of Figure 2-4.

Figure 2-4

Ion Gauge Pressure Analog Output.

A standard 1/8 in. miniature phono jack connector and plug are supplied.

The characteristics of this type of analog output voltage are ideal for applications requiring closed loop control. The voltage signal is smooth and continuous throughout all the decades of pressure measurement. This format is useful for computerized data acquisition because a simple equation

(finding the common antilogarithm) may be programmed to calculate pressure from the voltage output.

The equation is:

P = 10

(V-n)

Where V = analog output voltage; n = 12 for the 10 mA emission current range; n = 11 for the 1 mA emission current range; n = 10 for the 0.1 mA emission current range.

For example, if emission current is set to the 1 mA range and the analog output voltage is 3.25 volts, the pressure (in units selected) may be determined by raising 10 to the power (V-11) or

P = 10

(3.25-11)

= 1.8 x 10

-8

(Torr, for example)



41

2


2.4 Electrometer Calibration

Refer to Section 2.3 for instructions on calibrating ion gauge sensitivity and emission current.

Note that the two ion gauge collector inputs are in common so calibration inputs may be applied to either.

37 —

1 x 10-

9

Calibration Adjustment

This potentiometer calibrates the electrometer for very low inputs. Factory set, do not adjust.

Contact a Granville-Phillips application engineer for further information.

38 —

Electrometer Scale Adjustment

This is a factory calibration point and should not normally be changed by the user.

39 —

Overpressure Shutdown Adjustment

This control is factory set so the ion gauge will shut down when the pressure rises above the following levels:

Emission Current (milliamperes) Overpressure Point (Torr)

0.1 range 1 x 10

-2

1.0 range

10.0 range

1 x 10

-3

1 x 10

-4

The overpressure shutoff point does not depend on the adjustment of the emission level within a range.

To adjust the overpressure shutoff point to a different level:

1.

2.

3.

Maintain system pressure at the desired shutoff point.

Rotate the overpressure adjustment potentiometer fully counter-clockwise.

Turn on the ion gauge.

4.

Rotate the adjustment pot clockwise slowly until the IG turns off.

42 —

A/D Calibration

Factory set, do not adjust.

42

Figure 2-5

Ion Gauge Electrometer Module, Top View.



2


2.5 Electrometer Troubleshooting

Symptom

Electrometer underrange indicator

40

lit.

Possible Cause

Ion gauge collector unplugged. Collector cable defective. Failure of electrometer electronics.

Electrometer overrange indicator

41

lit.

Failure of electrometer electronics.

LED

43

or

44

current indicator lit.

emission under/over Failure of emission control under/over current indicator circuitry.

Not necessarily a failure on the electrometer board, unless lit continuously. Other possibilities include: short circuit in IG cable,

IG tube failure, IG power supply failure.

Microprocessor reset LED flashing.

45

lit or

A/D integration failure LED

46

lit.

Microprocessor failure.

IG collector unplugged.



43

2


2.6 Electrometer Module Specifications

Gauge Type

Pressure Range

Bayard-Alpert or compatible hot filament I.G.

Emission Range

Readable to:

Standard Electrometer

Readable to:

UHV Electrometer

.01 to .1 mA

1x10

-8

to

1x10

-1

Torr

1x10

-9

Torr

5x10

-10

to

1x10

-1

Torr

.1 mA to 1 mA

1x10

-9

to

1x10

-2

Torr

1x10

-10

Torr

5x10

-11

to

1x10

-2

Torr

Gas Type

Electronic Accuracy

N/A

Typically ± 3% of reading at ambient temperature = 25 ± 5 °C.

Resolution of IG Readout Scientific notation, 2 significant digits.

Display Update Time 0.5 sec typical Switch selectable to 3 sec/reading, averaged.

IG Tube Sensitivities

Emission Current

Collector Potential

Grid Potential

Filament Potential

Filament Current

Degas

Analog Output

1 mA to 10 mA

1x10

-10

to

1x10

-3

Torr

1x10

-11

Torr

5x10

-12

to

1x10

-3

Torr

3/Torr to 50/Torr (factory setting is 10/Torr).

10 µA to 10 mA in 3 decade ranges (factory setting is 1 mA)

0 V

+180 V

+30 V

0 - 6 A

EB: 10-40 watts (derate to 35 watts at 100 V line). I

2

R: 8 V, 10 A maximum (derate to 7V at 100V line). Power to gauge a function of cable length. Not recommended for standard cable lengths over 50 ft. Consult factory.

0-10 V; Logarithmic; 1 V/decade.

NOTE: Internal overpressure limiter is factory adjusted to trip at 1-decade below the upper

limits specified above. See Section 2.4 Electrometer Calibration on page 42 for readjustment

instructions.

44



Chapter 3

3

The Convectron Gauge Module

3.1 Safety Instructions

SAFETY PAYS. THINK BEFORE YOU ACT. UNDERSTAND WHAT YOU ARE GOING TO DO

BEFORE YOU DO IT. READ THIS INSTRUCTION MANUAL BEFORE INSTALLING, USING, OR

SERVICING THIS EQUIPMENT. IF YOU HAVE ANY DOUBTS ABOUT HOW TO USE THIS

EQUIPMENT SAFELY, CONTACT THE GRANVILLE-PHILLIPS PRODUCT MANAGER FOR THIS

EQUIPMENT AT THE ADDRESS LISTED ON THIS MANUAL.

3.1.1 Explosive Gases

Do not use the gauge tube to measure the pressure of combustible gas mixtures. The sensing element normally operates at only 125 °C but it is possible that momentary transients or controller malfunction can raise the sensor above the ignition temperature of combustible mixtures which might then explode causing damage to equipment and injuring personnel.

3.1.2 Limitation on Use of Compression Mounts

Do not use a compression mount (quick connect) for attaching the gauge tube to the system in applications resulting in positive pressures in the gauge tube. Positive pressures might blow the tube out of a compression fitting and damage equipment and injure personnel. The Convectron gauge should not be used above 1000 Torr (1333 mbar or 1.33 x 10

5

Pa).

3.1.3 Tube Mounting Position

If the gauge tube will be used to measure pressures greater than 1 Torr or 1 mbar, the tube must be mounted with its axis horizontal. Although the gauge tube will read correctly below 1 Torr when mounted in any position, erroneous readings will result at pressures above 1 Torr if the tube axis is not horizontal. Erroneous readings can result in over or underpressure conditions which may damage equipment and injure personnel.

3.1.4 Overpressure

Do not use Convectron gauges above 1000 Torr true pressure. Series 307 instruments are furnished calibrated for N

2

. They also measure the pressure of air correctly within the accuracy of the instrument. Do not attempt to use a Convectron gauge calibrated for N

2

to measure or control the pressure of other gases such as argon or CO

2

, unless accurate conversion data for N

2

to the other gas is properly used. If accurate conversion data is not used or improperly used, a potential overpressure explosion hazard can be created under certain conditions.

For example, at 760 Torr of argon gas pressure, the indicated pressure on a Convectron gauge calibrated for N

2

is 24 Torr. At an indicated pressure of 50 Torr, the true pressure of argon is considerably above atmospheric pressure. Thus if the indicated pressure is not accurately converted to true pressure, it is possible to overpressure your system. Overpressure may cause glassware such as ionization gauges to shatter dangerously, and if high enough may cause metal parts to rupture

thus damaging the system and possibly injuring personnel. See Section 3.4 Convectron Operation on page 50 for proper use of conversion data.

A pressure relief valve should be installed in the system if the possibility of exceeding 1000 Torr exists.



45

3


3.1.5 High Indicated Pressure

For some gases, be aware the indicated pressure will be higher than the true pressure. For example, at a true pressure of 9 Torr for helium the indicated pressure on a Convectron gauge calibrated for

N

2

is 760 Torr. The safe way to operate the gauge is to properly use accurate conversion data. See

Section 3.4 Convectron Operation on page 50 for proper use of conversion data.

3.1.6 Chemical

Cleaning solvents, such as trichloroethylene, perchloroethylene, toluene and acetone produce fumes that are toxic and/or flammable. Use only in areas well ventilated to the outdoors and away from electronic equipment, open flames, or other potential ignition sources.

3.1.7 Sensor Failure

If the gauge tube becomes disconnected from the controller or if the sensor wire in the gauge tube fails, the controller will indicate 9.9E+9. If the tube is unplugged from a powered controller, there may be an instantaneous (0 to 0.2 seconds) drop in the pressure indication and the process control relays could activate for this brief time, depending on the order in which the tube pins break contact.

3.1.8 Tube Contamination

The calibration of the gauge will be seriously affected by any gas which will attack the gold plated sensor, and could result in overpressurizing the system. Two primary gases in this category are mercury vapor and fluorine.

46



3


3.2 Convectron Module, Introduction

The Convectron Gauge (CG) Module provides pressure measurement from 1.0 x 10

-3

Torr (1.3 x

10

-3

mbar or 1.3 x 10

-1

Pa) to 1000 Torr, and one meaningful digit pressure indication down to 1 x

10

-4

Torr, air equivalent. Two transducers are displayed simultaneously in the second and third display lines, and are denoted here by “CGA” and “CGB” respectively.

Analog output (logarithmic in pressure, 1 volt per decade) is also provided. The Convectron can also be used to automatically turn on or off an ion gauge. When used with the Process Control

Module, the two gauges control four setpoints, in addition to the ion gauge turn-on setpoints.

3.3 Convectron Installation


Your instrument will have been shipped from the factory pre-set to display the units of measure, torr, millibar, or pascal, that you requested. If you wish to change units, proceed as follows:

1.

2.


Remove the top cover. Locate the

Convectron Module.

3.

4.

5.

6.

Locate

47

the millibar and units switches.

48

pascal

Leave both switches open for Torr units.

Close the appropriate switch for either millibar or pascal units.

Modify the units of measure of the electrometer to be consistent with the

Convectron.


Figure 3-1

Convectron Module,

Top View.

49 —


When “ON”, this switch enables pressure averaging. The display will be updated approximately every 3 seconds. When “OFF”, the update period is approximately 0.5 sec.

50

—

Not used.

47



3


3.3.2 Convectron Gauge Tube Installation

3.3.2.1 Important Precautions for Gauge Tube Installation

The following precautions in the use and installation of the Convectron gauge tube must be observed.

WARNING -

When high voltage is present, all exposed conductors of a vacuum must be maintained at earth ground.

Under certain conditions, dangerous high voltage can be coupled directly to an ungrounded conductor through a gas almost as effectively as through a copper wire connection. This hazard, which is not peculiar to this product, is a consequence of the ability of an electric current to flow through a gas under certain circumstances. A person may be seriously injured, or even killed by merely touching an exposed ungrounded conductor at high potential.

When high voltages are used within the vacuum system and the Convectron Gauge envelope is not reliably grounded through its vacuum connection, either a separate ground wire must be added, or the envelope must be shielded to positively prevent human contact. The gauge envelope may be grounded by using a metal hose clamp on the gauge connected by a #12 AWG copper wire to the grounded vacuum chamber.

High voltage can couple through a gas to the internal electrodes of a gauge. Do not touch the exposed pins on any gauge installed on a vacuum system where high voltage is present.

1.

Observe the precautions at the front of this chapter regarding tube mounting position and high pressure operation.

2.

3.

The gauge tube should be installed with the port oriented vertically downward to ensure that no system condensates or other liquids collect in the gauge tube.

Keep the tube clean. Do not remove the mounting port cover until you are ready to install the tube.

4.

5.

6.

7.

8.

Do not mount the gauge tube in a manner such that deposition of process vapors upon the internal surfaces of the tube may occur through line-of-sight access to the interior of the gauge tube.

Do not install the tube where high amplitudes of vibration are present. Excessive vibration will cause forced convection at high pressure giving erroneous readings.

Do not bake the tube to temperatures above 150 °C.

Do not install the gauge tubes where they will be exposed to corrosive gases such as mercury vapor, chlorine, or fluorine, which will attack the gold plated sensor.

For greatest accuracy and repeatability the gauge tube should be located in a stable room temperature environment.

48



3


3.3.3 Gauge Tube Orientation

It is important to consider the orientation of the gauge tube if accurate readings above 1 Torr are desired.

Below 1 Torr: The gauge tube will operate and accurately read pressures below 1 Torr when mounted in any orientation.

Above 1 Torr: The gauge tube will accurately read pressures above 1 Torr only when mounted with

its axis horizontal, preferably with the port pointing vertically downward, as shown in Figure 3-2. It

is valuable to point the port downward to facilitate the removal of condensation and other contaminants.

Furthermore, the gauge is factory calibrated with the port pointing vertically downward. Installation of the gauge with the port in other orientations may affect the accuracy of the indicated pressure.

Mounting clearance dimensions are shown in Figure 3-2.

Figure 3-2

Convectron Gauge Mounting.

3.3.3.1 Compression Mount (Quick Connect)

Do not use for positive pressure applications.

The gauge tube port is designed to fit a standard 1/2 in. compression (quick connect) mount such as the Cajon Co. Ultra-Torr

®

fittings.



49

3


50

Remove the caplug from the gauge tube port, insert the gauge tube port into the compression fitting and finger tighten the press ring. If a seal is not achieved it may be due to extreme cleanliness of the

O-ring. A light film of vacuum grease such as Apiezon

1

will insure sealing and is normally preferable to the use of pliers or pipe wrench to further tighten the press ring. You may point the electrical pins of the gauge tube anywhere you wish in a 360 degree horizontal circle for optimum routing of the gauge tube cable.

3.3.3.2 1/8 NPT Mount

The threads on the gauge tube port will fit a standard 1/8 NPT female fitting. Wrap the threads of the gauge tube port with Teflon

®

tape and screw these threads into the system fitting hand tight. Do not use any wrench or tool. The gauge tube body functions adequately as its own wrench. Tighten only sufficiently to achieve a seal. When the threads have been tightened to the point where a seal is just achieved, about one-half turn additional tightening is all that can be gained without overstressing the tube port. Be very careful in tightening so as not to damage the feedthrough pins projecting from the blue trim cover.

3.3.3.3 NW16KF Flange Mount

The KF mounting system requires an O-ring and centering ring to be placed between the mating flanges. The flanges are then held together with the aluminum flange clamp by tightening the wing nut. Maximum pressure for this style mounting system is 1000 Torr absolute.

3.4 Convectron Operation

3.4.1 Reading Pressure

WARNING - IF USED WITHOUT PROPER CALIBRATION OR WITHOUT

REFERENCE TO PROPER CALIBRATION TABLES, Convectron gauges can supply misleading pressure indications. This may result in dangerous overpressure conditions within the system. As supplied from the factory, the controller is designed to read pressure for nitrogen. For use with any other gases, consult the gas type correction charts found later in this manual.

The Convectron pressures are read in displays A and B of the 307 control unit. These pressures are displayed to 2 digits, except in the 10

-4

Torr range, where only 1 meaningful digit is displayed.

3.4.2 Special Considerations for Use Below 10

-3

Torr

During a fast pumpdown from atmosphere, thermal effects will prevent the Convectron from tracking pressure rapidly below 10

-3

Torr. After about 15 minutes readings in the 10

-4

range will be valid and response will be rapid. Calibration at vacuum may be performed at this time, or sooner if readings in the 10

-4

range are not needed.

The 10

-4

Torr range is accurate to about 0.1 milliTorr provided the instrument has been carefully

zeroed at vacuum. See Section 3.5 Convectron Calibration and Maintenance on page 60 for

vacuum and atmosphere calibration procedures. For accurate use in the 10

-4

Torr range, zeroing should be repeated frequently.

Pressure readings in the 10

-4

Torr range may differ from those found from ion gauges, since ion gauges usually lose sensitivity near their upper pressure limits.

1.

Trademark of James G. Biddle Co.



3


3.4.3 Use With Gases Other Than N

2

and Air

Before using the Convectron gauge to measure the pressure of other gases make certain the ATM

adjustment is correctly set for air. See Section 3.5 Convectron Calibration and Maintenance on page

60.

It is important to understand that the indicated pressure on a Convectron gauge depends on the type of gas in the tube, and on the orientation of the tube axis as well as on the gas pressure in the tube.

Convectron gauges are supplied calibrated for N

2

within the accuracy of the instrument. With certain safety precautions, the Convectron gauge may be used to measure pressure of other gases.

Convectron gauge tubes are thermal conductivity gauges of the Pirani type. These gauges transduce gas pressure by measuring the heat loss from a heated sensor wire maintained at constant temperature. For gases other than N

2

and air the heat loss is different at any given true pressure and thus the indicated reading will be different.

3.4.4 Indicated vs. True Pressure Curves

Figures 3-3 through 3-8 show the true pressure vs indicated pressure on Series 275 instruments for

eleven commonly used gases. Table 3-1 will help to locate the proper graph for a specific

application.

Table 3-1

Pressure vs. Indicated N

2

Pressure Curve.

3-4

3-5

3-6

3-7

3-8

Fig.

No.

3-3

Range and Units Gases

1 to 100 mTorr

0.1 to 1000 Torr

0.1 to 1000 Torr

10

-3

to 10

-1

mbar

0.1 to 1000 mbar

0.1 to 1000 mbar

All

Ar, C0

2

, CH

4

, Freon 12, He

D

2

, Freon 22, Kr, Ne, 0

2

All

Ar, C0

2

, CH

4

, Freon 12, He

D

2

, Freon 22, Kr, Ne, 0

2

Note that 1 mbar = 100 Pa, so the mbar charts may be used for pascal units by multiplying the values on the axes by 100.

A useful interpretation of these curves is, for example, that at a true pressure of 2 x 10

-2

Torr of CH

4 the heat loss from the sensor is the same as at a pressure of 3 x 10

-2

Torr of N

2

(see Figure 3-3 on page 53). The curves at higher pressure vary widely from gas to gas because the thermal losses at

higher pressures are greatly different for different gases.

The Convectron gauge tube utilizes convection cooling to provide resolution superior to any other thermal conductivity gauge near atmospheric pressure of N

2

and air. Because convection effects are geometry dependent, the true pressure vs indicated pressure curves for the Convectron gauge tube are likely to be much different from curves for heat loss tubes made by others. Therefore, it is not

51



3


safe to attempt to use calibration curves supplied by other manufacturers for their gauges with the

Convectron nor is it safe to use curves for the Convectron gauge with gauges supplied by other manufacturers.

If you must measure the pressure of gases other than N

2

or air, use Figures 3-3 through 3-8 to

determine the maximum safe indicated pressure for the other gas as explained below.

Example 1 –

Maximum safe indicated pressure.

Assume a certain system will withstand an internal pressure of 2000 Torr or 38.7 psia. For safety you wish to limit the maximum internal pressure to 760 Torr during backfilling. Assume you wish to

measure the pressure of argon. On Figure 3-4 on page 54 locate 760 Torr on the left hand scale,

travel to the right to the intersection with the argon (Ar) curve and then down to an indicated pressure of 24 Torr (N

2

equivalent). Thus in this hypothetical situation the maximum safe indicated pressure for argon is 24 Torr.

For safety, it is prudent to place a warning label on the instrument face which under the assumed conditions would read “DO NOT EXCEED 24 TORR FOR ARGON.”

Example 2 –

Indicated to true pressure conversion.

Assume you wish to determine the true pressure of argon in a system when the Convectron is

indicating 10 Torr. On Figure 3-4 on page 54, read up from 10 Torr (N

2

equivalent) indicated pressure to the argon curve and then horizontally to the left to a true pressure of 250 Torr. Thus 250

Torr argon pressure produces an indication of 10 Torr (N

2

equivalent).

Example 3 –

True to indicated pressure conversion.

Assume you wish to set a process control set point at a true pressure of 20 Torr of CO

2

. On Figure

3-4 on page 54, locate 20 Torr on the true pressure scale, travel horizontally to the right to the CO

2 curve and then down to an indicated pressure of 6 Torr (N

2

equivalent). Thus the correct process control setting for 20 Torr of C0

2

is 6 Torr (N

2

equivalent).

Example 4 –

True to indicated pressure conversion.

Assume you wish to obtain a helium pressure of 100 Torr in the system. On Figure 3-4 on page 54,

locate 100 Torr on the left hand scale, travel horizontally to the right to attempt to intersect the He curve. Because the intersection is off scale it is apparent that this true pressure measurement requirement for helium exceeds the capability of the instrument.

For gases other than those listed, the user must provide accurate conversion data for safe operation.

The Convectron gauge is not intended for use above 1000 Torr true pressure.

52



3


1

10

-1

10

-2

10

-3

O

2

He

Ne

Ar

Kr

10

-4

CH

4

D

2 freon 22 freon 12

CO

2

N

2

, air

Do not use this data with transducers other than the G-P Series 275

Convectron

®

Gauge.

Pressure units equivalence:

1

µ

m Hg = 1 mTorr = 1 x 10

-3

Torr

1000

µ

m Hg = 1 Torr

10

-4

10

-3

Indicated Pressure (Torr)

(nitrogen equivalent)

10

-2

Figure 3-3

Convectron Gauge Indicated vs. True Pressure Curve; 10

-4

to 10

-1

Torr.



10

-1

53

3


1000

freon 12

Ar

CO

2

N

2

, air

100

10

He

CH

4

1

54

10

-1

Use only when gauge axis is horizontal


Convectron

®

Gauge.


1

µ

m Hg = 1 mTorr = 1 x 10

-3

Torr

1000

µ

m Hg = 1 Torr

10

-2

10

-1

1 10



100

Figure 3-4


-1

to 1000 Torr.

1000



3


1000

100

10

1

Kr freon 22

N

2

, air

O

2

Ne

D

2



Convectron

®

Gauge.


1

µ

m Hg = 1 mTorr = 1 x 10

-3

Torr

1000

µ

m Hg = 1 Torr

10

-1

10

-2

10

-1

1

10



100

Figure 3-5


-1

to 1000 Torr.



1000

55

3


1

10

-1

10

-2

10

-3

O

2

He

Ne

Ar

Kr

10

-4

D

2

CH

4 freon 22 freon 12

N

2

, air

CO

2


Convectron

®

Gauge.


1 mbar = 100 pascal

56

10

-4

10

-3

Indicated Pressure (mbar)


10

-2

Figure 3-6


-4

to 10

-1

mbar.

10

-1



3


1000

freon 12

Ar

CO

2

N

2

, air

100

10

He

CH

4

1

10

-1



Convectron

®

Gauge.


1 mbar = 100 pascal

10

-2

10

-1

1 10



100

Figure 3-7


-1

to 1000 mbar.

1000



57

3


1000

100

10

1

Kr freon 22

N

2

, air

O

2

Ne

D

2



Convectron

®

Gauge.


1 mbar = 100 pascal

10

-1

58

10

-2

10

-1

1

10



100

Figure 3-8


-1

to 1000 mbar.

1000



3


3.4.5 Analog Output

On the rear panel are provided analog outputs for both gauges, see Refs.

51

and

52

. These are dc voltages proportional to the logarithm of the pressure, scaled to 1 volt per decade: 0 volts = 1 x 10

-4

or less,

Torr or mbar, 1 volt = 1 x 10

-3

, etc.

For pascal units, the analog output will be scaled to 0 volts = 1 x 10

-2

Pa.

Internal offset adjustments are provided which allow a shift in the analog output at 10

-4

Torr away from 0 volts to anywhere in the range -7 to +1 Vdc. This adjustment does not affect the slope of the analog

output vs pressure curve. See Section 3.5 on page 60

for adjustment.

Standard 1/8” miniature phono jack connectors are provided for the analog output.

Figure 3-9

Convectron Module

Rear panel.

Figure 3-10

Convectron Gauge Pressure Analog Output.



59

3


55

and

58

—

Filament Auto Turn-On

CGA may be used to automatically turn on IG1, and CGB to turn on IG2. Auto turn-on occurs when the CG pressure drops below the setpoint defined by the auto turn-on adjustment potentiometers.

The IG will also automatically be turned off when the pressure rises above this point.

The automatic off/on function will execute only once per setpoint crossing. For example, the IG may be turned off manually when below the setpoint, and the auto-on function will not turn it back on again until CG pressure has risen above the setpoint and once again dropped below.

The auto turn-on potentiometer is marked with rough pressure calibration markings. To set the pressure at which the IG will turn on with falling CG pressure, and off with rising pressure, simply adjust the pot to point to the desired pressure.

More precise control may be achieved by fixing the system pressure at the desired auto turn-on pressure, and adjusting the potentiometer slowly until the gauge comes on.

To disable the auto turn on function, adjust the CG auto turn-on pot

55

or

58

completely counter-clockwise

(“off”).

Figure 3-11

Convectron Module

Front Panel.

3.5 Convectron Calibration and Maintenance

Each gauge tube is individually calibrated for N

2

and air prior to leaving the factory. The Convectron gauge tube itself has a temperature compensated design. Each controller is also individually calibrated to provide accurate readout of N

2

and air pressure with any calibrated tube. Therefore,

initial calibration should not be necessary. See Table 3-1 on page 51 for use with gases other than

N

2

or air.

Calibration should be performed if accurate readings in the 10

-4

Torr range are desired, if the tube becomes contaminated, does not read correctly, or to readjust for use with long cables. For accurate calibration, the vacuum and atmosphere adjustments must be made in the following order. The gauge and controller can be calibrated as a system by performing the following steps:

1.

2.

a.

b.

54

and

57

—

Zero Adjustment

Evacuate the system to a pressure less than 1 x 10

-4

Torr.

With the gauge tube operating, adjust the VAC pot until 0.0 0 shows in the display. Note that if the adjustment is turned too far below zero, a minus sign will appear before the exponent (0.0 -0). Thus proper zero calibration is achieved when only 0.0 0 appears.

53

and

56

—

Atmosphere Adjustment a.

Allow the system pressure to rise to atmospheric pressure of N

2

or air.

60



3


b.

Adjust the ATM pot until the pressure displayed agrees with the absolute pressure as read on an accurate barometer. Use absolute pressure, not corrected to sea level.

NOTE: 1 atmosphere normal at sea level = 7.6 x 10

2

Torr = 1.0 x 10

3

mbar = 1.0 x 10

5

Pa.

59

—

Analog Output Full Scale

Adjustment

This potentiometer may be adjusted to calibrate the span of the analog output voltage to the factory setting of 1 volt per decade. This adjustment is common to both outputs.

60

and

61 —

Analog Output

Offset; gauges A and B

These potentiometers provide adjustable offset voltages to each analog output. The range of this adjustment allows setting the analog output at vacuum (P = 1 x 10

-4

Torr) anywhere in the range -7 to +1 Vdc.

The factory calibration is established by adjusting

60

59

and

61

to yield 0-volt outputs when both gauges are at vacuum

(pressure less than 1 x 10

-4

Torr), then adjusting to increase 1 volt for each decade the pressure increases.

Figure 3-12

Convectron Module

Top View.

3.5.1 Cleaning the Gauge Tube

The Convectron gauge may be baked to 150 °C. See Section 3.6 on page 62 for a list of materials

exposed to vacuum.

When the fine sensor wire is so contaminated with oil or other films that its emissivity or its diameter is appreciably altered, a change of calibration will result. Cleaning with trichloroethylene, perchloroethylene, toluene, or acetone is possible but it must be done very carefully so as not to damage the sensor.

CAUTION: The fumes from any of these solvents can be dangerous to your health if inhaled and they should be used in well ventilated areas exhausted to the outdoors. Acetone and toluene are highly flammable and should be used away from open flame or electrical equipment.

Hold the tube with the main body horizontal and the port projecting upward at an angle of 45 degrees and slowly fill it with solvent using a standard wash bottle with the spout inserted in the port to where it touches the screen. Let the solvent stand in the tube for at least ten minutes. Do not shake the tube if the tube is only partially filled as liquid forces on the sensor can become large enough to affect the transducer calibration. If the tube is completely filled, shaking is not helpful. To drain the tube, position it horizontally with the port facing downward. By slightly warming the tube, a positive pressure will build up internally forcing the solvent out past the screen. Then allow tube to dry overnight with port vertically downward and uncapped. Be certain no solvent odor remains before reinstalling tube on system.



61

3



The Convectron transducer is represented in Figure 3-13 as R1, R2, R3, and R4. These four

resistances form the legs of a bridge circuit, with R1 designating the sensor wire of the transducer.

R2 is a resistive network in the tube which compensates for changes in the ambient temperature. At bridge null, R1=R2xR3/R4. If there are no changes in ambient temperature, the value of R1 is a constant and the bridge is balanced.

Figure 3-13

Simplified Schematic Convectron Gauge Module.

As the vacuum system pressure is decreased, there are fewer molecules in the system to conduct the heat away from the sensor wire causing the temperature and resistance of R1 to increase. The increased resistance of R1 causes the bridge to unbalance and a voltage is developed across the null terminals. The bridge control circuit senses the null voltage and decreases the voltage across the bridge until the null voltage is again zero. When the bridge voltage is decreased, the power dissipated in the sensor wire is decreased causing the resistance of R1 to decrease to its previous value. The opposite events happen for a pressure increase. The bridge voltage is a non-linear function of pressure.

All materials have been chosen for ultra high vacuum service, corrosion resistance and bakeability to 150 °C. The gauge tube envelope is type 304 stainless steel. All metallic joints in the envelope are TIG welded. No solder is used within the envelope. The following materials are exposed to the vacuum: Type 304 stainless steel, Carpenter Alloy 52, Kovar

1

, Kapton gold plated tungsten, and borosilicate glass and Dow-Corning 9015 glass. The blue trim cover is molded of polysulfone thermoplastic suitable for service to 150 °C.

62

1.

Trademark of Carpenter Technology



3


3.7 Convectron Troubleshooting

3.7.1 Transducer Test Procedure

Do not perform electrical continuity tests with instruments applying in excess of 1 volt when the tube is at vacuum, or 5 volts when at atmospheric pressure.

The 275 transducer should show the following resistances (pin numbers are embossed on the transducer cap):

Pins 1 to 2

Pins 2 to 3

Pins 1 to 5

Any pin to envelope

20 to 25 ohms

50 to 60 ohms

175 to 190 ohms open circuit

If the resistance from pin 1 to 2 is about 800 ohms, the sensor wire is broken.

Figure 3-14

Convectron Module, Top view.



63

3


Table 3-2

Convectron Troubleshooting Guide.

Symptom

CGA overcurrent indicator

62

lit.

CGB overcurrent indicator

63

lit.

Indicators

64

or

65

lit.

Indicator

66

lit.

Indicator

67

lit.

Microprocessor reset LED

68

lit or flashing.

A/D integration failure indicator flashing.

69

lit or

Display reads 9.9 +9.

Display reads -

Pressure reading very inaccurate.

Possible Cause

Cable short, pins 1-3.

Cable short, pins 1-3.

Circuit failure.

CGB unplugged; broken sensor wire.

CGA unplugged; broken sensor wire.


Circuit failure.

Broken sensor wire.

Tube or cable at controller unplugged.

Controller out of calibration, unknown gas type, tube mounted in the wrong orientation, sensor damaged (e.g., by reactive gas), tube very dirty, extremes of temperature or mechanical vibration.

3.8 Convectron Specifications

Gauge Type

Pressure Range

Display Resolution

Gas Type

Display Update Time

Analog Output

G-P Series 275

1 x 10

-4

Torr to 990 Torr, N

2

equivalent.

2 significant digits, except for 1 significant digit in 10

-4

Torr decade.

N

2

, Air

0.5 sec typical. Switch selectable to 3 sec/reading, averaged.

Logarithmic, 1V/decade, Factory set to 0-7 Vdc. Adjustable offset

+1 Vdc to -7 Vdc. 10 mA maximum current.

64



Chapter 4

4

The Thermocouple Gauge Module


The Thermocouple Gauge (TC) Module for the Granville-Phillips 307 Vacuum Gauge Controller provides pressure measurement from 1 X 10

-3

Torr (1.3 X 10

-3

mbar or 1.33 x 10

-1

Pascal) to 1 Torr.

Two transducers are displayed simultaneously in the second and third display lines, and are denoted here by “TCA” and “TCB” respectively.

Analog output is also provided. The thermocouple gauge can also be used to automatically turn on or off an ion gauge. When used with the process control, the two gauges control four setpoints, in addition to the ion gauge turn-on setpoints.

4.2 Thermocouple Gauge Module Installation


Your instrument will have been shipped from the factory pre-set to display the units of measure; Torr, millibar or Pascal, that you requested. If you wish to change units, proceed as follows:

1.


2.

Remove the top cover. Locate the thermocouple gauge pc board

3.

4.

5.

6.

Locate

70

, the millibar, and units switches.

71

, the Pascal,

Leave both switches open for Torr units. Close the appropriate switch for either millibar or

Pascal units.

Modify the units of measure of the electrometer to be consistent with the thermocouple gauge module.


Figure 4-1

Thermocouple Module, Top View.

72

—


When “ON”, this switch enables pressure averaging. The display will be updated approximately every 3 seconds.

73 —

Not used.



65

4


4.2.2 Thermocouple Gauge Tube Installation

The 307 VGC thermocouple gauge module is designed to operate with Granville-Phillips 270006 or

comparable transducers. (See Section 4.6 Thermocouple Gauge Specifications on page 70 for other

compatible transducers).

The thermocouple gauge tubes may be installed anywhere in the system using a 1/8 NPT or .410 in. compression connection, or may be welded directly. Do not use compression fittings for positive pressure applications. If installed in an area where condensable vapors are present, mount with the open end pointing down to allow drainage.

4.3 Thermocouple Gauge Operation


The thermocouple gauge pressures are read in displays A and B, the second and third display lines, of the 307 control unit. Since thermocouple gauges have negligible resolution at pressures above 1

Torr, the instrument overflows to a pressure of 9.9 +9 at pressures above 1 Torr. If the gauge is reading “above atmosphere” the display will read 99 +9, that is, the decimal point disappears. For the bargraph display, the last 2 elements on the right will blink for the “above atmosphere”

condition. This can be used in the atmosphere calibration procedure (see Section 4.4

Thermocouple Gauge Calibration on page 68).


On the rear panel are provided analog outputs for both gauges,

74

and

75

. The voltage is 0 to

10 volts dc, non-linear. See Figure 4-2.

Standard 1/8” miniature phono jack connectors are provided for the analog output.

Figure 4-2

Thermocouple Gauge Module

Rear Panel.

66



4


Figure 4-3

Thermocouple Gauge Pressure Analog Output.

4.3.3 Filament Auto Turn-On

TCA may be used to automatically turn on IG1, and TCB to turn on IG2. Auto turn on occurs when the TC pressure drops below the setpoint defined by the auto turn-on adjustment potentiometers,

77

and

79

. The IG will also automatically be turned off when the pressure rises above this point.

The automatic on/off function will execute only once per setpoint crossing. For example, the IG may be turned off manually when below the setpoint, and the auto-on function will not turn it back on again until TC pressure has risen above the setpoint and once again dropped below.

The auto turn-on pot is marked with rough pressure calibration markings. To set the pressure at which the IG will turn on with falling

TC pressure, and off with rising pressure, simply adjust the pot to point to the desired pressure.

Figure 4-4

Thermocouple Gauge Module, Front Panel.



67

4


More precise control may be achieved by fixing the system pressure at the desired auto turn-on pressure, and adjusting the potentiometer slowly until the gauge comes on.

To disable the auto turn on function, adjust the auto turn-on pot completely counter-clockwise

(“OFF”).

4.4 Thermocouple Gauge Calibration

76

and

78 —

Zero Adjustment

1.

Evacuate the system to a pressure less than 1 x 10

-3

Torr (if bargraph display proceed to

Step 2).

2.

With the gauge tube operating, adjust the VAC pot until a single “0” shows in the display. Note that if the adjustment is turned too far below zero, a minus sign will appear in the display. Thus proper zero calibration is achieved when only the “0” appears.

88

and

89 —

Atmosphere Adjustment

Calibration at atmosphere is performed at the factory and should not normally be attempted by the user. However, if necessary, proceed as follows:

1.

2.

Allow the system pressure to rise to atmospheric pressure.

Remove the top of the control unit.

3.

Adjust the atmosphere potentiometer,

88

for TCA or

89

for TCB, until the pressure display is 9.9 x 10+9. Note that when adjusted beyond this point, the decimal point of the display will disappear, “perfect” calibration is achieved when the decimal point just disappears. However, the resolution of the gauge at this point is very poor, and the appearance or disappearance of the decimal point during normal operation when the gauge is at atmosphere is no cause for concern.

68



4


4.5 Thermocouple Gauge Troubleshooting

Refer to Figure 4-5 to find the indicator LEDs on the thermocouple printed circuit board.

Table 4-1

Troubleshooting Guide.

Symptom

Indicator LED

80

lit.

Indicator

81

lit.

Indicators

82

or

83

lit.

Indicators

84

or

85

lit.

Indicator

86

lit.

Indicator

87

lit.

Display reads 9.9 +9.

Pressure reading very inaccurate.

Tube reads at or below zero, or above atmosphere at all times.

Possible Cause

Cable short or circuit failure (TCB).

Cable short or circuit failure (TCA).

Circuit failure or TCB out of calibration.

Circuit failure or TCA out of calibration.


Circuit failure.

Tube unplugged.

Tube out of calibration or contaminated. Controller out of calibration.

Controller out of calibration.

Figure 4-5

Thermocouple Gauge Module, Top View.



69

4


4.6 Thermocouple Gauge Specifications

Gauge Type

Pressure Range

Display Resolution

Gas Type

Display Update Time

Analog Output

Voltage

Maximum Current

G-P 270006, Comptech TVT-6000, or Teledyne-Hastings DV-6M, DV-6R,

DV-36, DV-20, or equivalent.

10

-3

Torr to 1 Torr Nitrogen or air equivalent.

2 significant digits

N

2

or Air.

0.5 sec typical, switch selectable to 3 sec/reading, averaged.

0-10 Vdc nonlinear.

5 mA.

70



5

Chapter 5

The Process Control Module

It is the installer's responsibility to ensure that the automatic signals provided by the product are always used in a safe manner. Carefully check the system programming before switching to automatic operation.

Where an equipment malfunction could cause a hazardous situation, always provide for fail-safe operation. As an example, in an automatic backfill operation where a malfunction might cause high internal pressures, provide an appropriate pressure relief device.

5.1 Introduction to the Process Control Module

A Process Control Module provides the 307 Vacuum Gauge Controller with single-pole, double-throw relays that may be controlled either by digital setpoints or by the built-in manual override switches.

The Process Control Module may be purchased with 2 or 6 channels. The first 2 channels are assigned to the ion gauges. If present, channels 3 and 4 are assigned to CGA or TCA; and 5 and 6 to

CGB, TCB, or CMB.

Switches are provided to assign channel 1 to IG1, IG2, or both; and likewise for channel 2.

All six channels have selectable polarity for activation above or below the setpoint.

The six-channel process control module can also be purchased with user assignable channels for

gauges. This configuration is noted with a “C” in the catalog number (307###-##C-##). See Section

5.4.

5.2 Process Control Module Installation

5.2.1 Process Control System Connections

Prior to connecting the process controls to the system, it is recommended that the following steps be followed. If application assistance is desired, contact a Granville-Phillips application engineer.

a.

b.

c.

d.

e.

f.

Unless the control logic is simple and obvious, develop a logic diagram of the process control function.

Prepare a specification table which lists the proposed pressure setting, system measurement point, and polarity for each PC channel.

Draw a circuit schematic which specifies exactly how each piece of system hardware will be connected to the 307 process control relays.

With the Process Control Module connector disconnected, connect the process control cable to the devices to be controlled.

Ensure that all devices are under manual control before connecting to the Process Control

Module.

Attach a copy of the process control circuit diagram to this manual for future reference and troubleshooting.



71

5


The process control connector is embossed with letters identifying each pin. The following table shows the letters designating the 3 pins assigned to each of the 6 channels:

Figure 5-1

Pin Assignments/Connector.

5.3 Process Control Operation

At all times the status of the 6 relays are displayed in the relay status LEDs on the 307 front panel

90

. Note that these LEDs do not indicate whether the gauge pressure is above or below the programmed setpoint, since setpoint polarity and manual override status may result in activation above or below the setpoint.

72

Figure 5-2

Process Control Relay Status Lights.

5.3.1 Setpoint Display and Adjustment

Setpoints are stored in non-volatile memory, and are specified by a 1-digit mantissa and 2-digit exponent. They may be set anywhere in the range 1 x 10

-12

to 9 x 10

+5

. This allows for the entire pressure range of all supported transducer types and systems of units.

The setpoint is compared directly to the display data, so units of measure are implicit. Changing the units switch on the gauge control modules will not change the stored setpoints. They must be re-programmed in the new system of units.

If a setpoint is set to “above atmosphere” then the relay will always be activated (unless its polarity

is reversed, see Section 5.3.3 Relay Polarity Setting on page 74), except during overflow conditions

that occur, e.g. when an ion gauge is first powered up, or a Convectron gauge is disconnected. If it is desired that a process control be held in one state, the manual override switch should be used. If the setpoint is adjusted below 1 x 10

-12

to 0 then it will always be deactivated (unless polarity is reversed).



5


To Display a Setpoint

1.

Be sure the “CAL” switch of the electrometer is in its center position, or the calibration data in display line 1 will conflict with the display of setpoints 1 and 2.

2.

Adjust the thumbwheel

94

to the number of the channel you wish to display.

3.

Press either setpoint display/set button,

92

or

93

and release. The setpoint will appear for

2 seconds in the same display line as the associated transducer;

Setpoints 1 and 2 appear in display 1.



To Modify a Setpoint

1.

2.

3.

Adjust the thumbwheel

94

to the number of the channel you wish to modify.

Press and hold the setpoint SET button for the direction you wish the setpoint to change, up,

92

, to raise the setpoint, down, to lower it.

93

,

The setpoint will scroll until the button is released. It will scroll slowly until a decade boundary is crossed and then will speed up to facilitate rapid changes across many decades. Release the button when you have entered the desired decade, and then re-depress it to scroll slowly within the decade to reach the exact setpoint needed.

Figure 5-3

Process Control Module,

Front Panel.

After the setpoint button is released, the display will return to pressure data after two seconds. At this time the new setpoint will be deposited in non-volatile memory.

5.3.2 Points to Consider in Using the Process Control Module

If the ion gauges are both off, PC relays 1 and 2 will deactivate, regardless of polarity setting.

If neither the Convectron nor the Thermocouple Gauge Module are present, channels 3-6, if present, will always be deactivated.

No change in status of relays 1 and 2 will occur during degas. They will function as if the pressure was frozen at the instant degas was initiated. This is because large pressure variations may occur in an ion gauge tube under degas.

There is a programmed 10% hysteresis on each process control setpoint. For example, with a pressure setpoint of 6.3 Torr the relay will activate when the display reaches 6.2 Torr (for falling pressure) and will deactivate when the pressure rises to one significant digit above the setpoint plus 10%, i.e., 6.3 + 0.6 + 0.1 or 7 Torr. For setpoints where the second digit is 0.5 or greater the 10% value is rounded up. For example, if the setpoint is programmed to 6.6 Torr the relay will activate at 6.5 Torr (on falling pressure) and will deactivate when the pressure rises to 6.6

+ 0.7 + 0.1 or 7.4 Torr.



73

5


Since the process control and computer interface modules derive their pressure data directly from the display bus, they will be unable to update their pressure data while setpoints are being displayed. They will not mistakenly interpret setpoint data as pressure data, but will simply retain the last displayed pressure data until the SET key is released.

If the thumbwheel setting is changed while a setpoint is being displayed, this change will not take affect until the display has been released and the SET key depressed another time.

5.3.3 Relay Polarity Setting

The relays can be set to activate with pressure either above or below the setpoint. A switch is provided for each channel. For activation below the setpoint, the switch should be in the OFF position. This is the factory setting. Refer to the numbers on the printed circuit board--not on the switch body itself--for the channel number. Note

96

is the switch for channel 6.

74

Figure 5-4

Process Control Module,

Top View.

5.3.4 Ion Gauge Assignment

Process Control channels 1 and 2 are controlled by the ionization gauge. Process Control channel 1

(PC1) operates relay K1 and Process Control channel 2 (PC2) operates relay K2. Ion Gauge 1 (IG1),

Ion Gauge 2 (IG2), or both can be assigned to operate either PC1 or PC2. Switches

100

and

99

are used to assign IG1 and IG2 to PC1 (K1). Switches

98

and

97

are used to assign IG1 and

IG2 to PC2 (K2). The following tables define the process control operation for each combination of switch settings.

Table 5-1

K1 (PC1) Relay.

Switch IG1

100

OFF

OFF

Switch IG2

99

OFF

ON

ON

ON

OFF

ON

Function

Relay K1 can turn on when IG1 is ON or when IG2 is ON.

Relay K1 can turn on when IG1 is ON and will turn off when IG2 is ON.

Relay K1 will turn off when IG1 is ON and can turn on when IG2 is ON.

Relay K1 will always be off.



5


Table 5-2

K2 (PC2) Relay.

Switch IG1

98

OFF

Switch IG2

97

OFF

Function

Relay K2 can turn on when IG1 is ON or when IG2 is ON.

OFF

ON

ON

OFF

Relay K2 can turn on when IG1 is ON and will turn off when IG2 is ON.

Relay K2 will turn off when IG1 is ON and can turn on when IG2 is ON.

ON ON Relay K2 will always be off.

The Figure 5-5 shows the status of the process control relay contacts for the ON and OFF

conditions.

NC

Relay ON Pole

NO

NC

Relay OFF Pole

NO

Figure 5-5

Process Control Relay Contacts Status.

See Figure 5-1 on page 5-72 for Process Control connector relay contact/pin assignments.

91 —

Manual Override

These six three-position switches on the front of the process control module allow override of the programmed setpoints at any time. When moved to the right, the relay is activated. When moved to the left, the relay is deactivated. When left in the center position, the relay is controlled automatically.

75



5


5.4 Process Control with User Assignable Gauges

The user assignable process control module for the Series 307 VGC allows versatile assignment of setpoints to the various gauges. The 10-

position DIP Switch S7 on the process control module (Figure 5-6) is

used to select the gauge and the polarity selection of the relays. This process control module is the same as the 6-channel process control module with the following exceptions:

a.

b.

c.

Relay Polarity Setting: The relays will activate only when the pressure is below the set point or when the Manual

Override switch is ON. The relays cannot be programmed to activate on rising pressure.

Ion Gauge Assignment: Do not use the information in

Section 5.3.3 and Section 5.3.4. Use the gauge assignment

information provided in Table 5-3.

Gauge Assignment: Use Switch S7 on the process control module to select the gauge. Set the DIP switches according

to the settings shown in Table 5-3.

Figure 5-6

Process Control Module with

User Assignable Gauges

Table 5-3

Process Control User Assignable Switch Settings - Switch S7, #1 - #10

Gauge

Assignment Switch #

PC1 S7-1

Switch #

S7-2

Gauge

Assignment Switch # Switch #

PC4 S7-7 S7-8

IG *

CG/TC A

CG/TC/CM B

Disabled

IG *

PC2

CG/TC A

CG/TC/CM B

ON

ON

OFF

OFF

S7-3

ON

ON

OFF

ON

OFF

ON

OFF

S7-4

ON

OFF

ON

IG *

CG/TC A

CG/TC/CM B

Disabled

IG *

PC5

CG/TC A

ON

ON

OFF

OFF

S7-9

ON

OFF

ON

OFF

ON

OFF

Disabled

PC3

IG *

CG/TC A

OFF

S7-5

ON

ON

OFF

S7-6

ON

OFF

PC6

IG *

CG/TC/CM B

S7-10

ON

OFF

CG/TC/CM B

Disabled

OFF

OFF

ON

OFF

IG = Ion Gauge; CG = Convectron Gauge; TC = Thermocouple Gauge; CM = Capacitance Manometer

* Assigning a set point to IG causes the process control relay to activate for either IG 1 or IG 2.

76



5


5.5 Process Control Theory of Operation

The process control module contains a dedicated microcontroller and a nonvolatile memory chip for storage of the setpoints. This chip has a rated life of 10,000 erase/write cycles for each setpoint, and will retain data for 10 years. Since data is read/written to this chip serially, it is necessary to store working copies of the setpoints in internal RAM memory.

The microcontroller compares the setpoints with the pressure display data on the display bus and makes a decision as to whether or not to activate a channel's relay.

The manual override switches, when thrown in one direction or the other, take precedence over the microcontroller's decision.

5.6 Process Control Troubleshooting

If LED

95

is lit or flashing, there is a probable circuit failure.

The setpoints are read from non-volatile memory into RAM when the unit powers up. On power up, a checksum is computed and stored in RAM, and is updated whenever a setpoint is changed. It is then periodically re-computed from the existing setpoints and checked against the pre-existing value. If for any reason (such as a power fluctuation or electrical transient in the system) a setpoint becomes corrupted, this method will usually trap the error. If this occurs the fault relay will be activated, and will remain activated until power is cycled on the 307 control unit.

If a setpoint is found to contain data which is not a valid setpoint, the setpoint will be set to 0.

5.7 Process Control Specifications

Number of channels

Pressure range

Hysteresis

Setpoint adjustment

Output relays

Contact rating

Contact style

Polarity

2, or 6

1.0 x 10

-12

to 9.9 x 10

+5

. Setpoints are compared directly to display data and must be reprogrammed if the measurement units, Torr, mbar, or Pascal, are changed.

10%

Digital, 2 significant digits plus exponent.

5A @ 120 Vac, 4A @ 240 Vac resistive or 5A @ 30 Vdc.

SPDT.

Switch selectable for activation with pressure above or below setpoint. Factory set for activation below. (Activation with pressure below the setpoint, only, for User Assignable gauge configuration.)

77



5


78



Chapter 6

6

The RS-232 Module


The RS-232 Interface Module for the 307 Vacuum Gauge Controller allows data output to, and ion gauge control by, a host computer. Output is either by a command-response mechanism or by a talk-only mode which is invoked via a switch on the RS-232 board.

A variety of baud rates and byte framing options are available, as well as switches to force the handshake lines to an “always true” condition.

6.2 RS-232 Installation

307 RS-232 factory defaults are: 300 BAUD, 7 data bits, no parity, 2 stop bits; DCD, CTS, DSR forced “true”.

The interface protocol is set using 8 switches. Reference switch number 1.

101

in Figure 6-1 on page 80 designates

6.2.1 Selecting the Byte Format

6.2.1.1 Baud Rate

Dip switches 6-8 are used to control the baud rate. The settings are shown in Table 6-1:

Table 6-1

Dip Switches for Controlling Baud Rate.

S6 S7 S8 Baud Rate

On On On 9600

On On Off

On Off On

On Off Off

Off On On

Off On Off

Off Off On

Off Off Off

4800

2400

1200

600

300

150

75



79

6

The RS-232 Module

80

6.2.1.2 Character Framing

Switches 3-5 control number of characters, parity, and number of stop bits:

Table 6-2

Dip Switches for Number of Characters, Parity and

Number of Stop Bits.

S3 S4 S5 CHARACTER

BITS

PARITY STOP

BITS

On On On 8 None 2

On On Off

On Off On

On Off Off

Off On On

Off On Off

Off Off On

Off Off Off

7

7

7

7

7

8

8

Even

Odd

None

Even

Odd

Even

Odd

1

2

2

2

1

1

1

6.2.1.3 Talk-Only Mode

Switch S1,

101

, if off at power-up, puts the interface in talk-only mode. The pressure data from all three displays will be output in a single message string, separated by commas, approximately every 5 seconds.

If neither the Convectron nor Thermocouple Gauge

Modules are present, only the ion gauge pressure will be output.

6.2.1.4 Handshake Line Control Switches

Refer to Section 6.4 RS-232 Theory of Operation on page 84 for more detailed information on the

handshaking mechanism.

Switches

102

,

103

, and

104

, when in the “up” position, force the handshake lines data-carrier-detect

(DCD), clear-to-send (CTS), and data-set-ready (DSR), respectively, to a logic true condition. As shipped from the factory, these lines are forced true.

Figure 6-1

RS-232 Module,

Top View.



6

The RS-232 Module

6.2.1.5 Invert RTS Switch

As shipped from the factory, the request-to-send (RTS) control line is set to operate as a modem line per the RS-232 standard. In some implementations it is necessary to invert this line and hook it directly to the clear-to-send (CTS) line of the host computer.

Switch S2, if OFF when the 307 goes through its power-up sequence, tells the RS-232 interface to

invert the polarity of the RTS line. See Section 6.4 RS-232 Theory of Operation on page 84, for more

details.

6.3 Operation

Consult the user's manual for the host computer to be sure the protocol used is in accord with that established via the switch configuration you have chosen for the 307 RS-232 module.

Communication with the 307 VGC is via ASCII strings. A message to 307 consists of a command and a command modifier, followed by a terminator. The message may contain leading spaces, and the command and modifier may optionally be separated by spaces or commas. No spaces may appear within the command or the modifier, only between them.

The terminator expected by 307 is an ASCII carriage-return line-feed, denoted here by CRLF. The carriage-return is optional, and messages terminated with only the line-feed will be accepted. Note that the CRLF terminator is in general appended automatically, by the host computer's interface software, to the message string supplied by the user.

If extra characters are found in the message after it has been successfully interpreted but before the terminator, they will be ignored.

All characters should be upper-case.

All messages to 307 will receive a reply, consisting of an ASCII string terminated with CRLF.

Numbers will be returned in the format X.XXE±XX.

6.3.1 Command Syntax

DG

Definition: Turn degas on or off

Modifiers:

Response:

ON or OFF

OK if command accepted, or INVALID if rejected.

From 307: OKCRLF

NOTES

1.

2.

Command is INVALID if neither IG is on.

A response to the DG ON command of OK indicates only that a signal requesting degas has been sent to the electrometer. Degas may fail to activate, e.g., if the pressure is above 5 x 10

-5

Torr, or if your 307 does not have degas capability. Use the DGS command (see below) to verify that degas has been successfully initiated.

81



6

The RS-232 Module

DGS

Definition: Display degas status

Modifiers: None

Response: ASCII 1 if degas is on, 0 if degas is off

From 307: 1CRLF

(Indicating degas is on)

DS

Definition: Display pressure reading

Modifiers:

Response:

IG1 or IG2 or IG or CG1 or CG2

ASCII string representing the pressure for the selected gauge

From 307: 1.20E-03CRLF

NOTES

1.

The DS CG1 and DS CG2 commands are used to display the pressures from the second 2 display lines, with either the Convectron, Thermocouple, or Capacitance Manometer Gauge

Module installed.

2.

3.

If the requested ion gauge is turned off, or is in its first few seconds of operation, or data is requested from a Convectron, Thermocouple, or Capacitance Manometer Gauge when none is installed, the 307 will return 9.90E+09.

The DS IG command will return pressure from whichever ion gauge is on, and 9.90E+09 if neither ion gauge is on.

IG1

Definition: Turn IG1 on or off

Modifiers:

Response:

ON or OFF

OK if command accepted, INVALID if rejected


NOTES

1.

The IG1 ON command will be rejected as INVALID if IG1 is already on, and IG1 OFF will be rejected if IG1 is already off.

2.

A response to the IG1 ON command of OK indicates only that a signal requesting that IG1 be turned on has been sent to the electrometer. The tube may fail to come on, e.g., if the system pressure is too high or if the tube is disconnected. To verify that IG1 is on, use the DS IG1 command. If the tube is off (or in its first few seconds of operation after being turned on) a pressure of 9.90E+9 will be returned.

82



6

The RS-232 Module

IG2

Identical to IG1, but applies to IG2.

PCS

Definition: Display process control channel status

Modifiers:

Response:

1 or 2 or 3 or 4 or 5 or 6 or B or none.

Depends on modifier:

Modifier = single digit (1 through 6); response = single ASCII digit, 0 if the corresponding relay is inactive, 1 if active.

Modifier = B; response = a byte of data with bits 0 through 5 set/clear according to whether the corresponding relay is active/inactive. Bit 6 will always be set to guarantee that the returned byte will not appear as a terminator byte.

Modifier absent; response will be a string of 6 ASCII 0's and 1's separated by commas giving the status of all six channels.

Examples: Assume that channels 1 - 3 are active, and 4 - 6 are inactive.

From computer: PCS 1 CRLF

From 307: 1CRLF

From computer: PCS B CRLF

From 307: GCRLF

NOTE: Note that ASCII “G” corresponds to the bit pattern 01000111 and represents the status of the PC channels.

From computer: PCS CRLF

From 307: 1,1,1,0,0,0CRLF

6.3.2 Error Messages

If an error is found in the incoming message, the following messages will be returned in place of the normal response:

OVERRUN ERROR Returned if the incoming message overflows 307's buffer. This may indicate a flaw in the host software.

PARITY ERROR Returned if the parity of a byte in the incoming message does not match that programmed by the switches.

SYNTAX ERROR Returned if the message fails to parse as a valid 307 command. Could also result from failure to assert DCD during transmission to 307.

83



6

The RS-232 Module

6.4 RS-232 Theory of Operation

6.4.1 Handshaking

The 307 RS-232 interface implements the signals given in Table 6-3.

Table 6-3

RS-232 Control Lines.

Signal

Protective Ground

Transmitted Data

Received Data

Request to Send (RTS)

Clear to Send (CTS)

Data Set Ready (DSR)

Signal Ground (common return)

Data Carrier Detect (DCD)

Data Terminal Ready (DTR)

7

8

20

3

4

5

6

Pin # Direction

1 -

2 To Computer

To 307

To Computer

To 307

To 307

-

To 307

To Computer

The DTR line is set true by 307 on power up to indicate it is on line. When 307 receives a start bit on the received data line it will input and buffer a character. The DCD line must be true at the time each character is received or that character will be ignored. 307 will continue to receive and buffer characters until the terminator (LF) is received.

Upon receiving the terminator, 307 will assert the RTS line as a holdoff, to prevent the host computer from attempting to transmit further data until the message just received has been parsed and a reply has been output.

During output of the reply, the incoming handshake lines CTS, and DSR are tested prior to beginning transmission of each character. 307 will wait until both are true before beginning transmission of a character, and will not test them again until ready to begin transmitting the next.

After transmitting the terminator, 307 will negate RTS and wait for the next incoming message.

To summarize:

CTS, DSR

Set by the computer to indicate that 307 may output the next byte in its message. As shipped from the factory these lines are forced “TRUE” by the switch settings of the 307 RS-232 printed circuit

board, thus 307 will automatically assume the host is ready to receive. See Figure 6-1 on page 80

for the location of these switches.

84



6

The RS-232 Module

DCD

Tested by 307 when a character is received. The character will be ignored unless DCD is “TRUE”. As shipped from the factory this line is forced “TRUE” by the switch settings.

DTR

Always asserted by 307. A “power on” indication.

RTS

Negated by 307 on power-up. Asserted by 307 upon receipt of a message terminator.

Negated after transmitting the terminator of 307's response to that message.

Reversing the Polarity of RTS

If switch 2,

105

, is open on power-up, 307 will apply the opposite polarity to RTS from that described above.

When used in this mode RTS may be connected to the

CTS input of the host computer. This violates the RS-232 standard, but is a commonly used implementation.

Figure 6-2

RS-232 Module,

Top View.

6.5 RS-232 Troubleshooting

Because the RS-232 “standard” is found in a bewildering array of configurations, the first thing to do if trouble arises is check the following configuration options:

1.

2.

3.

Check switch settings.

Be sure baud rate, character format and framing, and interface protocol are matched to your host computer or terminal's requirements. Note that there may be several mismatched parameters. Check to see if your computer requires the reversed-polarity RTS convention.

Check interface wiring.

The pin designations for the RS-232 connector are shown in Figure 6-2. Note that the

“received” and “transmitted” data lines are defined as seen by the 307. Many companies supply “null modems” or switch boxes for the purpose of reconfiguring the control lines for particular applications.

Check command format.

Be sure the strings you output to the 307 are in accord with the syntax defined in Section 6.3

Operation on page 81.

85



6

The RS-232 Module

Table 6-4

RS-232 Troubleshooting Guide.

Symptom

Microcontroller reset LED

106

flashing.

lit or

No response or garbled output.

Possible Cause

Microcontroller failure.

OVERRUN ERROR message.

PARITY ERROR message.

SYNTAX ERROR message.

Baud rate incorrect. Character length incorrect or stop bit(s) incorrect.

Stop bit(s) incorrect, host software failure.

Parity incorrect.

Message to 307 not in accord with specified syntax. Could also result from failure to assert DCD handshake line.

6.6 RS-232 Specifications

Format

Data Rates

EIA standard RS-232-C, half duplex, asynchronous.

75,150,300,600,1200,2400,4800,9600 baud.

Character length 7 or 8 bit ASCII, switch selectable.

Parity Odd, even, or none, switch selectable.

Stop bits

Handshake

Logic levels

1 or 2 (8 character bits plus parity allows only 1 stop bit)

Outputs: DTR, RTS (RTS polarity selectable)

Inputs: DSR, CTS, DCD. May be forced to logic “TRUE” with switches.

Inputs: Logic 1 2.0 Vdc min., 15 Vdc max.

Logic 0 -15 Vdc min., 0.75 Vdc max.

Input Current: 4.0 mA max @ Vin = +15 Vdc

-4.0 mA max @ Vin = -15 Vdc.

86



Chapter 7

7

The RS-485 Module

7.1 RS-485 Introduction

The RS-485 communications option for the Series 307 Vacuum Gauge Controller permits data output to, and gauge control by, a host computer using RS-485 digital communications.

Communications handshake is by a command-response mechanism.

A variety of baud rates and byte framing options are available. The RS-485 byte format is configured to your system requirements using configuration switches located on the option board. These switches are accessed by removing the controller top chassis cover.

The RS-485 factory defaults are:

9600 BAUD, 8 character bits, no parity, 1 stop bit, Address = 01

Internal switches are read upon power up. Changes in settings will take effect upon next power-up cycle.

7.2 RS-485 Installation

7.2.1 RS-485 Address

The address dial on the RS-485 module on the back of the controller and Switch S1determine the controller’s RS-485 address. This address can be any hex code from 00 to FF.

The address dial on the RS-485 module on the back of the controller determines the value of the least significant digit and the S1 switches determine the value of the most significant digit. The S1

switch positions are binary and the weight of each switch when OFF is given in Table 7-1.

To prevent data contentions, no two RS-485 nodes should be set with the same address. It is not recommended that address 00 be used because some manufacturers use this address for configuration.

Figure 7-1

Back Panel and Top View of RS-485 Module

Table 7-1 Switch Weight When OFF

Switch Weight

S1.1

10 Hex

S1.2

S1.3

S1.4

20 Hex

40 Hex

80 Hex



87

7

The RS-485 Module

7.2.2 Response Delay for the RS-485 Interface

Switch S2.1 enables a delay of the response from the module of 10 to 13 MS + 10 bit times when

OFF. When S2.1 is ON, the delay is greater than 700 microseconds. The factory default setting is

ON, with a delay greater than 700 microseconds.

7.2.3 Selecting the Byte Format for RS-485 Communications

Baud rate for the RS-485 communications is determined by the settings of switches S2.6, S2.7 and

S2.8. Table 7-2 defines the baud rate base on the switch settings. The factory default baud rate

setting is 9600.

Table 7-2

Baud Rate Switch Settings

S2.6

ON*

ON

ON

OFF

OFF

OFF

OFF

S2.7

ON*

OFF

OFF

ON

ON

OFF

OFF

S2.8

OFF*

ON

OFF

ON

OFF

ON

OFF

Baud Rate

9600*

4800

2400

1200

600

300

150

7.2.4 Character Framing for the RS-485 Computer Interface

Character framing for the RS-485 computer interface is determined by setting switches S2.3, S2.4,

and S2.5. Table 7-3 defines the character bits, parity, and stop bits based on the switch settings. The

factory default setting is S2.3 On, S2.4 Off, and S2.5 Off - Character bits set to 8, Parity None, and

Stops bits at 1.

Table 7-3

Character Framing Switch Settings

S2.3

ON

ON

ON

ON

OFF

OFF

OFF

OFF

S2.4

ON

ON

OFF

OFF

ON

ON

OFF

OFF

S2.5

ON

OFF

ON

OFF

ON

OFF

ON

OFF

Character Bits

8

8

7

7

8

8*

7

7

Parity Stop Bits

None 2

Even 1

Odd

None*

Even

Odd

Even

Odd

1

1

1

1*

2

2

* factory setting

88



7

The RS-485 Module

7.2.5 Connecting the RS-485 Computer Interface

Connectors J1 and J2 on the rear of the control unit are wired parallel and are interchangeable.

Connection can be made by daisy chaining gauge controllers together with the signal from the host computer going into one connector, then out the other connector to another gauge controller.

Figure 7-2

RS-485 Connector

The maximum total cable length is 4,000 ft. No more than 32 devices can be connected to one RS-

485 communications line. When an RS-485 network is in an idle state, all nodes are in listen

(receive) mode. Under this condition there are no active drivers on the network. In order to maintain the proper idle voltage state, bias resistors must be applied to force the data lines to the

idle condition.Table 7-3 illustrates the placement of bias resistors on a host computer, 2-wire

configuration, for the typical 5 volt and 24 volt systems.

Figure 7-3

RS-485 Bias Resistor

89



7

The RS-485 Module

In a four wire configuration connect TX on the gauge controller to RX on the host computer and connect RX on the gauge controller to TX on the host computer. If the computer sends and receives data on 2 wires, connect the RS-485+ from the computer to both the +TX and +RX Pins (Pins 4 and

8), and connect the RS-485 from the computer to both -TX to -RX (Pins 5 and 9). Table 7-4 shows

the proper wire connections for a 2-wire connection.

When connecting multiple 307 Controllers, connect TX to TX and RX to RX on all controllers.

The polarity may have to be reversed on the computer and other instruments—you may have to try it both ways. No damage will result if connections are wrong.

90

Figure 7-4

RS-485 Connectors

Table 7-4

RS-485 Specifications

Function

Communications Format

Data Rate

Character Length

Parity

Stop Bits

Handshake

Address

Number of Connections

Total Cable Length

Connectors

Specification

RS-485, half-duplex, asynchronous

9600 (Default), 4800, 2400, 1200, 600, 300, 150 baud

8-bit or 7-bit ASCII (Factory default is 8-bit)

No parity, even or odd (Factory default is None)

1 or 2 (Factory default is 1)

None (Poll/Response)

256 selectable combinations (Factory default is 01)

Up to 32 devices

4,000 feet maximum

Two 9-pin D-sub (Parallel)



7

The RS-485 Module

7.3 Preparing for use of the RS-485 Computer Interface

The Series 307 Vacuum Gauge Controller uses a command-response half-duplex protocol. If the controller recognizes received data as a valid command, it will check the command string address and compare with its own. If the addresses match, the controller will process the command and then respond. In all configurations, only one twisted pair will have data transmissions in one

direction at any time. The timing of the data transfer is shown in Table 7-5. T0 is 10-13 mS + 10 bit

times with S2.1 in the OFF position, T0 is greater than 700 microseconds with S2.1 in the ON position, and T1 is greater than 300 microseconds. Adhering to these timing constraints will ensure data is not overwritten.

Figure 7-5

RS-485 Data Timing

Consult the user's manual for the host computer to be sure the character framing settings used are in accord with that established via the switch configuration you have chosen for the RS-485 module.

Communication is via ASCII strings. A message to consists of a start character “#”, an address “AA”, command, and a command modifier, followed by a terminator. The message may contain leading spaces, and the command and modifier may optionally be separated by spaces. No spaces may appear within the command or the modifier, only between them.

The address expected is programmed via the switch settings on the rear of the module. The syntax is

“#AA” where AA is an ASCII representation of the hex address of the controller. The terminator expected is an ASCII carriage-return denoted here by CR. Note that the terminator is sometimes appended automatically, by the host computer's interface software, to the message string supplied by the user. If extra characters are found in the message after it has been successfully interpreted but before the terminator, they will be ignored.

All messages will receive a reply, consisting of an ASCII string terminated with CR. Pressure numbers will be returned in the format X.XXE±XX.

Messages may use upper or lower case alpha-numeric characters. The controller will always respond with upper case characters.



91

92

7.4 RS-485 Command Syntax

IG1

Definition:

Modifiers:

Response:

Example:

Turn IG1 on or off.

ON or OFF

OK if command accepted, INVALID if rejected.

From computer: IG1 ONCRLF

From 307 controller: OKCRLF

NOTES

1.

The IG1 ON command will be rejected as INVALID if IG1 is already on, and IG1 OFF will be rejected if IG1 is already off.

2.

A response to the IG1 ON command of OK indicates only that a signal requesting that IG1 be turned on has been sent to the electrometer. IG1 may fail to come on, e.g., if the system pressure is too high or if the gauge is disconnected. To verify that IG1 is on, use the DS IG1 command. If the gauge is off, or in its first few seconds of operation after being turned on, a pressure of 9.99E+9 will be returned.

IG2

Identical to IG1, but applies to IG2.

DG

Definition:

Modifiers:

Response:

Example:

Turn degas on or off

ON or OFF


From computer: DG ON CRLF

From 307 controller: OKCRLF

NOTES

1.

2.

Command is INVALID if neither IG is on.

A response to the DG ON command of OK indicates only that a signal requesting degas has been sent to the electrometer. Degas will not activate if the pressure is above 5 x 10-5 Torr. Use the DGS command (see below) to verify that degas has been successfully initiated.

DS

Definition:

Modifiers:

Response:

Example:

Display pressure reading.

IG1 or IG2 or IG or CG1 or CG2.

ASCII string representing the pressure for the selected gauge.

From computer: DS CG1 CRLF

From 307 controller: 1.25E-03CRLF

NOTES

1.

The DS CG1 and DS CG2 commands are used to display the pressures from the lower 2 display lines with the Convectron Gauge Module installed.

2.

If the requested ion gauge is turned off, or is in its first few seconds of operation, or data is requested from a Convectron Gauge when none is installed, the Control Unit will return

9.90E+09.

The DS IG command will return pressure from the gauge which is on, and 9.99E+09 if neither is on.



7

The RS-485 Module

DGS

Definition:

Modifiers:

Response:

Example:

Display degas status.

None

ASCII 1 if degas is on, 0 if degas is off.

From computer: DGS CRLF

From 307 controller: 1CRLF

PCS

Definition:

Modifiers:

Response:

Display process control channel status.



Modifier = single digit (1 through 6); response = single ASCII digit, 0 if the corresponding relay is inactive, 1 if active. See Example 1.


See Example 2.

Modifier absent; response will be a string of 6 ASCII 0's and 1's separated by commas giving the status of all six channels. See Example 3.

Assume that channels 1 - 3 are active, and 4 - 6 are inactive: Examples:

1.

From computer: PCS 1 CRLF

From 307 controller: 1CRLF

2.


From 307 controller: GCRLF

(Note that ASCII “G” corresponds to the bit pattern 01000111 and represents the status of the

PC channels in bits 0 through 5).

3.

3.From computer: PCS CRLF

From 307 controller: 1,1,1,0,0,0 CRLF

Error Messages

If an error is found in the incoming message, the following messages will be returned in place of the normal response.

OVERRUN ERROR - Returned if the incoming message overflows the controller’s buffer.

SYNTAX ERROR - Returned if the message fails to parse as a valid controller command.

93



7

The RS-485 Module

7.5 RS-485 Troubleshooting

In the event of problems with the RS-485 communications verify the following items for proper configuration.

1.

Check the configuration switch settings.

Ensure the baud rate, character framing, and interface protocol are matched to the host computer or terminal’s requirements. Note that there may be several mismatched parameters.

2.

Check command format.

Ensure that the command strings output from the host computer or terminal to the 307 Controller are in accordance with the syntax defined by this addendum.

Table 7-5

RS-485 Troubleshooting Guide

Symptom

Micro-controller reset LED CR1 illuminated or flashing

Possible Cause

Micro-controller failure.

No response or garbled output

Intermittently will not respond

Baud rate incorrect, character length incorrect, character framing incorrect, or bias resistors do not exist or are incorrect.

Poor cable connections, ground fluctuations (the maximum common mode potential across the system is 7 volts) and EMI from other sources.

Bias resistors do not exist or are incorrect. If the start character is not received properly, the controller may not interpret it as a start character and the controller will not respond. Host software must be prepared to resend a command if a response is not generated within a reasonable period of time.

OVERRUN ERROR message

PARITY ERROR message

SYNTAX ERROR message

Stop bit(s) incorrect, host software failure.

Parity incorrect.

Message to Controller not in accord with specified syntax.

94



Chapter 8

8

The IEEE 488 Module


The IEEE 488 Module for the 307 Vacuum Gauge Controller allows data output to, and ion gauge control by, a host computer. Output is either by a command-response mechanism or by a talk-only mode which is invoked via a switch on the IEEE 488 board.

For those who want to configure the 488 bus to operate via SRQ interrupts, a switch is provided which will cause the 307 to generate an SRQ and wait for a serial poll before outputting each message.

8.2 IEEE 488 Installation

8.2.1 Selecting the Interface Bus Address

Refer to Figure 8-1, switch No. 1 is shown by

107

. Each instrument on the IEEE 488 bus has an address from 0 to 30.

The address is set at the factory to 8. The user must ensure that every device on his bus has a unique address. To select an address, use switches 1 through 5 to adjust the address according to the following binary weight values. Setting a switch to OFF adds the value of the numbered switch to the address sum. See Table 8-1, below.

Figure 8-1

IEEE 488 Module Top View.

Table 8-1

Switches for setting the Interface Bus Address

Switch #: 5

Value:

Examples

4

16 8

Setting

Setting

Setting

On

On

Off

Off

On

Off

3

4

On

Off

Off

2

2

On

Off

On

1

1

Off

Off

On

=

=

= address 9 address 7 address 28



95

8


8.2.2 Talk-only Mode

Switch 8,

109

, if set to off on power-up, puts the interface in talk-only mode. The pressure data from all three displays will be output in a single message string, separated by commas, approximately every 5 seconds. If neither the Convectron nor Thermocouple Gauge Modules are present, only the ion gauge pressure will be output. The factory default is talk-only disabled.

8.2.3 SRQ Mode

Switch 7,

108

, if set to off on power-up, tells the interface to generate an SRQ interrupt and expect a serial poll before every message output. Currently, the factory default is SRQ mode disabled

(switch 7 “ON”), but early 307's were shipped with SRQ enabled.

The serial poll response byte will contain a 1 in bit 6 (the second-highest bit). Bit 5 will be set if an error has occurred. In this case the pending message will be an error message.

8.3 IEEE 488 Operation

Communication with 307 is via ASCII strings. A message to 307 consists of a command and a command modifier, followed by a terminator. The message may contain leading spaces, and the command and modifier may optionally be separated by spaces or commas. No spaces may appear within the command or the modifier, only between them.

The terminator accepted by 307 is an ASCII carriage-return line-feed, denoted here by CRLF. The carriage-return is optional, and messages terminated with only the line-feed will be accepted. Note that the CRLF terminator is in general appended automatically, by the host computer's interface software, to the message string supplied by the user.

A terminator is not required, if the last character of the message to the 307 VGC is accompanied by the EOI bus signal. If extra characters are found in the message after it has been successfully interpreted but before the terminator, they will be ignored. All characters should be upper-case.

All messages to 307 will receive a reply, consisting of an ASCII string terminated with CRLF, the LF being accompanied by EOI. Numbers will be returned in the format X.XXE+/-XX.

8.3.1 Command Syntax

DG

Definition: Turn degas on or off

Modifiers:

Response:

ON or OFF



NOTES

1.

Command is INVALID if neither IG is on.

2.

A response to the DG ON command of OK indicates only that a signal requesting degas has been sent to the electrometer. Degas may fail to activate, e.g., if the pressure is above 5 x 10

-5

Torr, or if your 307 does not have degas capability. Use the DGS command (see below) to verify that degas has been successfully initiated.

96



8


DGS

Definition: Display degas status

Modifiers: None

From 307: 1CRLF

(Indicating degas is on)

DS

Definition: Display pressure reading.

Modifiers: IG1 or IG2 or IG or CG1 or CG2.

Response: ASCII string representing the pressure for the selected gauge.

From 307: 1.20E-03CRLF

NOTES

1.

2.

The DS CG1 and DS CG2 commands are used to display the pressures from the second 2 display lines, with either the Convectron, Thermocouple, or Capacitance Manometer Gauge

Module installed.

If the requested ion gauge is turned off, or is in it's first few seconds of operation, or data is requested from a Convectron, Thermocouple, or Capacitance Manometer Gauge when none is installed, the 307 will return 9.90E+09.

3.

The DS IG command will return pressure from whichever gauge is on, and 9.90E+09 if neither is on.

IG1

Definition: Turn IG1 on or off

Modifiers:

Response:

ON or OFF

OK if command accepted, INVALID if rejected


NOTES

1.

The IG1 ON command will be rejected as INVALID if IG1 is already on, and IG1 OFF will be rejected if IG1 is already off.

2.

A response to the IG1 ON command of OK indicates only that a signal requesting that IG1 be turned on has been sent to the electrometer. The tube may fail to come on, e.g., if the system pressure is too high or if the tube is disconnected. To verify that IG1 is on, use the DS IG1 command. If the tube is off (or in its first few seconds of operation after being turned on) a pressure of 9.90E+9 will be returned.

97



8


IG2

Identical to IG1, but applies to IG2.

PCS

Definition: Display process control channel status.

Modifiers:

Response:



Modifier = single digit (1 through 6); response = single ASCII digit, 0 if the corresponding relay is inactive, 1 if active.


Modifier absent; response will be a string of 6 ASCII 0's and 1's separated by commas giving the status of all six channels.

Examples: Assume that channels 1 - 3 are active, and 4 - 6 are inactive:

From computer: PCS 1 CRLF

From 307: 1CRLF


From 307: GCRLF

(Note that ASCII “G” corresponds to the bit pattern 01000111 and represents the status of the PC channels in bits 0 through 5).

From computer: PCS CRLF

From 307: 1,1,1,0,0,0CRLF

8.3.2 Error Messages

If an error is found in the incoming message, the following messages will be returned in place of the normal response, and if the SRQ mode is used, bit 5 in the serial poll response byte will be set.

OVERRUN ERROR

Returned if the incoming message overflows 307's buffer.

SYNTAX ERROR

Returned if the message fails to parse as a valid 307 command.

98



8


.

8.4 IEEE-488 Troubleshooting

If your interface fails to function, first verify the following:

1.

Switch settings.

2.

3.

Be sure the controller knows the address of the 307 as set by the dip switches. Be sure the system controller does not reserve certain addresses for system devices, e.g., a printer. Be sure the 307 is not in the talk-only mode unless desired for data logging. Be sure, if the

SRQ mode is set, that your controller performs a serial poll in response to the SRQ from the 307 VGC.

Check interface wiring.

Be sure the cable is good; try swapping in a known good cable (IEEE 488 cables are available from

Granville-Phillips). Check for too many devices on the bus or too great a total bus length (> 20 meters). Too many devices could cause problems due to capacitive loading.

Check command syntax.

Be sure you are following the syntax specified in

Section 8.3 IEEE 488 Operation on page 96.

Figure 8-2

IEEE 488 Module Top View

Table 8-2

IEEE 488 Troubleshooting Guide

Symptom Possible Cause


110

lit. Microcontroller failure.

OVERRUN ERROR message.

SYNTAX ERROR message.

Host software failure.

Message to 307 not in accord with specified syntax.

8.5 IEEE 488 Specifications

Capability codes SH1, AH1, T5, L4, SR1, RL0, PP0, DC0, E1, OT0, C0

99



100



Chapter 9

9

The Convectron/Capacitance

Manometer Module


The capacitance manometer module allows pressure measurement from 1.0 x 10

-4

Torr to 1000

Torr, depending on transducer pressure range. Up to 250 mA of +15 VDC power supply current is available for temperature-compensated transducers.

The module also operates one Convectron gauge. Please see Chapter 3, The Convectron Gauge

Module, in this manual for information on the use of the Convectron gauge.

When a six channel process control module is installed, the capacitance manometer can be used to control the two channels associated with display line "B", channels 5 and 6. The associated "A"

Convectron gauge controls channels 3 and 4.

Analog output is provided for both gauges; the output is linear with pressure for the manometer, and logarithmic for the Convectron.



Your instrument will have been shipped from the factory pre-set to display the unit of measure; torr, millibar, or pascal, that you requested. If you wish to change units, proceed as follows:

1.

2.


Remove the top cover. Locate the capacitance manometer pc board.

3.

4.

Locate

111

switches.

, the millibar, and

112

the pascal, units

Leave both switch open for torr units. Close the appropriate switch for millibar or pascal units.



Figure 9-1

Convectron/Capacitance Manometer,

Top View.

101

9

The Convectron/Capacitance Manometer Module

5.

6.

Modify the units of measure of the electrometer module to be consistent with the capacitance manometer module.


113

—


When "on" this switch enables filtering which will stabilize a "jumpy" display. The display wills be updated approximately every 3 seconds.

114 —

Not used.

115 —

Convectron Gauge Controls

See Chapter 3, The Convectron Gauge Module for

information on use of Convectron controls.

Figure 9-2

Capacitance Manometer Module,

Front Panel.

116 —

Capacitance Manometer Vacuum Calibration

See Section 9.4 Calibration on page 104.

117 —

Capacitance Manometer Range Switch

Your capacitance manometer transducer has a maximum pressure indication of 1, 10, 100, or 1000

Torr. Set this switch accordingly.

9.2.2 Capacitance Manometer Cable Installation

The cable supplied by Granville-Phillips for this module connects to both a Convectron gauge and a capacitance manometer. Since electrical connectors to capacitance manometers are not

standardized, Granville-Phillips provides cables terminated with tinned wire leads. Figure 9-3 on page 103 shows the color-coded functions of the wires. Please consult the manual for your

capacitance manometer transducer for information on electrical connection, and installation of the transducer in your vacuum system.

The 307 VGC will display pressures from capacitance manometer transducers with 0 to 10 Vdc outputs and provide power to transducers requiring ± 15 Vdc inputs. The 307 VGC may also be used as a readout device for capacitance manometers which require 115 Vdc power input, such as the MKS 220B. To wire the 307 to such a transducer, connect the white (+ signal), and brown (signal ground) wires to the manometer as directed in the transducer instruction manual. Insulate the remaining red (+15 V), black (power ground) and blue (-15 V) wires at the manometer end of the

307 cable. Connect the transducer to a 115 Vac power source as directed in your capacitance manometer instruction manual.

102



9


Figure 9-3

Capacitance Manometer Module, Cable.

9.3 Operation


The capacitance manometer pressure is read in the third display line of the 307 controller. The accompanying Convectron gauge is read in the second display line. If the cable is disconnected, the manometer will read 0 pressure.


On the rear panel are provided analog outputs for both the Convectron gauge,

118

and capacitance manometer,

119

.

Standard 1/8 inch miniature phono jack connectors are provided for the analog output.

The analog output for the capacitance manometer is a dc voltage proportional to the pressure with a range of 0 to

10 volts, proportional to the transducer output. See the documentation for your transducer for a description of this output.

Internal adjustments are provided for zero offset and

full-scale (gain) control. See Section 9.4 Calibration on page 104 for adjustment.

Figure 9-4

Capacitance Manometer Module,

Rear Panel.

103



9


104

9.4 Calibration

9.4.1 Initial Transducer Calibration

When first installed, your transducer zero-adjust should be set using a voltmeter to read zero when at a system pressure below the minimum pressure range of the transducer. Please refer to the documentation accompanying your capacitance manometer transducer for instructions on this procedure. You should also at this time adjust the VAC on the 307 controller

116

, with the gauge not attached to the controller, per the instructions below. After this initial setup has been performed, the routine fine-tuning of the transducer zero may be performed with the module front panel zero adjust potentiometer. The zero can be adjusted to 0 ± 200 mV.

To Set The Controller Zero (Initial Controller Setup):

1.

Disconnect the capacitance manometer cable either at the gauge head or at the controller.

2.

Adjust the vacuum potentiometer

116

until the third display line shows a single "0". If the adjustment is turned too far, a minus sign will appear in the display. This proper calibration is achieved when only the "0" appears.

To Zero The 307 VGC with the Transducer:

1.

Be sure the transducer was zeroed properly on initial installation, see your transducer documentation.

Connect the cable from the 307 VGC to the

capacitance manometer transducer per Figure 9-3 on page 103.

2.

3.

Evacuate your system to below the minimum rated pressure of your transducer.

Adjust the vacuum potentiometer

116

until the third display line shows a single "0". If the adjustment is turned too far, a minus sign will appear in the display.

This proper calibration is achieved when only the "0" appears.

128

,

130 —

Convectron Controls

See Section 3.5 Convectron Calibration and Maintenance on page 60 of this manual.

129

—

Capacitance Manometer Analog Output

Offset Adjust

This potentiometer is used to set analog output 2 at zero pressure. This value is affected by the vacuum adjust potentiometer

116

. The output can be adjusted to between

-0.02 and +0.02 volts at zero pressure.

Figure 9-5

Capacitance Manometer Module

131 —

Capacitance Manometer Analog Output Full-Scale Adjust

This is a span or gain control, with a range of 0.93 to 1.3. Factory setting is for a gain of 1.0, thus 10 volts in from the transducer (maximum readable pressure) = 10 volts out from 307 at the factory setting.



9


132 —

Capacitance Manometer Full-Scale Adjust

This potentiometer controls the full-scale readout of the 307 capacitance manometer display. The control is adjusted at the factory for a full-scale display with an input of 10.0 volts. After zeroing the controller as described above, the 307 may be calibrated to the transducer by adjusting the full-scale adjust pot so the 307 display corresponds to the pressure of the manometer at or near the maximum pressure. This reference pressure may be determined by a certified standard gauge, a dead weight calibration system, or a standard voltage reference. The full-scale adjust pot and the

CM analog out full-scale pot do not interact and may be adjusted independently.


Within the capacitance manometer, a diaphragm is distorted by the pressure of the gas in the system under measurement. This diaphragm forms part of a capacitor, and its deflection causes changes in capacitance. Thus, the electrically measured capacitance is a measure of pressure. The device is very sensitive to the elastic properties of the metal of the diaphragm. For this reason, large pressure excursions, such as occur when the system is raised to atmospheric pressure, can cause offsets to the pressure reading. The diaphragm is also extremely sensitive to temperature effects, and although it may be held in a temperature controlled chamber, this temperature control is never perfect, resulting in further perturbations to the devices theoretical accuracy.

Note that these perturbations are inherent in the capacitance manometer design and are not a property of the electronic module used to operate the transducer.

Capacitance manometers are capable of exceptional accuracy, and read pressure independent of gas type, but are also subject to zero-point drift, and must be calibrated at vacuum frequently if high accuracy is to be obtained. Refer to the manual for your transducer for instructions.

9.6 Capacitance Manometer Troubleshooting

Refer to Figure 9-4 on page 103 to locate LEDs on the capacitance manometer circuit board.

Table 9-1

RS-232 Troubleshooting Guide.

Symptom

Unstable reading

Display always reads 0.

Indicator LED

120

on.

Indicator LED

121

on.

Indicator LED

122

on.

Indicator LED

123

on.

Indicator LED

124

.

Indicator LED

125

on.

Indicator LED

126

on.

Indicator LED

127

on.

Possible Cause

Mechanical vibration of capacitance manometer, faulty system ground or cable ground.

Capacitance manometer cable unplugged, no ±15 V power, faulty cable.

-15 V over-current. Defective cable, transducer, or circuit board.

Convectron gauge unplugged.

A/D failure. Defective A/D converter circuit.

+15 V overcurrent. Defective cable, transducer, or circuit board.

Not used.

Defective PC board, Convectron bridge circuit.

Convectron over-current. Defective gauge or cable.


105



9



See Chapter 3, The Convectron Gauge Module for additional specifications.

Gauge Type Any capacitance manometer transducer that requires ±15 Vdc power at

≤ 250 mA and outputs 0-10 Vdc proportional to pressure.

0.01% of full-scale (as limited by display resolution).

Accuracy

Display Resolution

Pressure Range

Display Update Time

Output to Head

Input from Head

Analog Output

Highest 3 decades - 2 digits, lowest decade - 1 digit, scientific notation.

1, 10, 100, 1000 Torr max heads, 4 decades of pressure.

Unfiltered: 0.5 sec. typical. Switch selectable filtering: 3 sec. (average of 6 readings).

±15 V ±2% at 250 mA.

0-10 Vdc into 100 Kohm.

5 mA max.

Analog Output Speed Limited by transducer speed.

Cable Connection Cable termination is bare tinned wire, user terminates to transducer.

106



Chapter 10

10

Linear Analog Output Module


The Linear Analog Output Module provides three, zero to +10 Vdc, linearized voltages that correspond to the displayed pressure readings of the 307 VGC. The source for these outputs is the digital data on the controller's internal bus to the Display Module. The analog output resolution is therefore dependent upon this data. The module is intended to be used in a 307 VGC configured with an ion gauge (top display) and two thermocouples (middle and bottom display). The pressure range for the IG linear output is selected by a front panel switch. Four separate ranges are available.


The Module is installed in the controller in the slot normally assigned to the computer interface module.

10.2.1 Electrometer (IG) Range Selection

The purpose of the electrometer linear analog output is to linearize a 3-decade segment of the 0-10

Vdc logarithmic output. The segment selected is determined by the position of the IG range switch on the front panel of the module. One of four ranges may be selected. The range selected will allow linear analog output for pressures from 1 x 10

-n

to 1 x 10

-m

. Set the IG range switch, shown in

Figure 10-1, to the desired pressure range.

Figure 10-1

Linear Analog Output Module,

Front Panel.

Figure 10-2

Linear Analog Output Module,

Top View.

107



10


10.2.2 Cable Connections

The output is via a “D” type 9-pin connector for which the mating parts have been supplied. The pin

assignment for the output connector is defined in Table 10-1:

10.2.3 Pin Assignment

Table 10-1

Pin Assignments.

7

9

3

5

Pin(s)

1, 2, 4, 6 & 8

Function

Ground (both signal and chassis)

IG log analog output

TC “A” output

IG linear output

TC “B” output

NOTE: Pin 3 is the logarithmic analog output from the electrometer module. This voltage is

proportional to the pressure determined by the IG. Refer to Section 2.3 Operation on page 38 for

further details.

10.3 Operation

The Linear Analog Output Module is in operation anytime power is “on”. There are no accessible controls or adjustments.

NOTE: During periods where the front panel display is not showing pressure, the analog outputs will lock up at the last valid pressure reading. This includes the period when a process control setpoint is displayed and when emission current or sensitivity is being displayed for the IG channel.

108



10


10.4 Calibration

Internal zero and full scale adjustment potentiometers are available for the three analog output channels. Adjustment should be rarely, if ever, required.

Table 10-2

Adjustment Potentiometers.

Figure 10-2

Reference

Potentiometer

Designator

Function

138

R11 IG zero adjust

137

R12 IG full scale adjust

R21 TC “A” zero adjust

136

135

R22 TC “A” full scale adjust

134

R30 TC “B” zero adjust

133

R31 TC “B” full scale adjust

10.4.1 IG Zero Adjust

To adjust the IG linear output, set the displayed pressure to a reading that gives an analog output equal to 0.100 Vdc for the range selected. For example, on the 10

-6

to 10

-3

range set the display for a reading of 1.0 x 10

-5

Torr. Adjust

138

for an output of exactly 0.100 Vdc.

10.4.2 IG Full Scale Adjust

Set the display to read the maximum pressure for the range selected. For example, set the display to read 1.0 x 10

-3

Torr for the 10

-6

to 10

-3

range. Adjust

137

for an output of exactly 10.0 Vdc.

NOTE: It is not necessary to perform the above adjustments each time a new range is selected.

Performing the calibration on any range will calibrate the IG linear analog output for all ranges.

10.4.3 TC Zero Adjust

Set the thermocouple display to read “0” (zero). Adjust T. C. Zero.

(

136

for channel A or

134

for channel B) for exactly 0.00 Vdc on the appropriate TC output.

10.4.4 TC Full Scale Adjust

Set the thermocouple display to read 1.0 torr. Adjust T.C. Full Scale ( for channel B) for exactly 10.0 Vdc on the appropriate TC output.

135

for channel A or

133


The Linear Analog Output Module circuit consists of an embedded microcontroller and associated circuitry. The microcontroller picks off display data to the display module during the appropriate bus timing cycles and performs a digital-to-analog conversion by using the external circuitry.

109



10


10.6 Troubleshooting

Table 10-3

Troubleshooting Linear Analog Output Module.

Symptom


139

lit or flashing.

Possible Cause

Microcontroller failure.

There are no other user troubleshooting procedures associated with the Linear Analog Output

Module. If you are having difficulty with this module, contact Granville-Phillips Customer Service.


Analog output loading: ± 2mA max.

10.7.1 Thermocouple Output

Table 10-4

Thermocouple Output.

Pressure

Decade Range

(torr)

< 10

-3

Torr

10

-3

Torr

10

-2

Torr

10

-1

Torr

≥ 1 Torr

Output

Voltage

0 Vdc

10 - 99 mV

.1 V - .99 V

1.0 V - 9.9 V

10.0 V

Smallest

Increment

-

1 mV

10 mV

-

100 mV

Comment

Zero Vdc output below 1 mT

1 mV = .1 mTorr

10 mV = 1 mTorr

100 mV = 10 mTorr

110



10.7.2 Electrometer (IG) Output

Table 10-5

Electrometer (IG) Output.

Pressure Decade

Range (torr)

< 10

-

3

10-3

10-2

10-1

≥ 100

Output

Voltage

< 10.0 mV

10.0 mV - 99 mV

0.1 V - 0.99 V

1.0 V - 9.9 V

10.0 V

< 10-6

10-6

10-5

10-4

≥ 10-3

< 10-7

10-7

10-6

10-5

≥ 10-4

< 10-8

10-8

10-7

10-6

≥ 10-5

< 10.0 mV

10.0 mV - 99 mV

0.1 V - 0.99 V

1.0 V - 9.9 V

10.0 V

< 10.0 mV

10.0 mV - 99 mV

0.1 V - 0.99 V

1.0 V - 9.9 V

10.0 V

< 10.0 mV

10.0 mV - 99 mV

0.1 V - 0.99 V

1.0 V - 9.9 V

10.0 V

Smallest

Increment

—

1.0 mV

10.0 mV

0.1 V

—

—

1.0 mV

10.0 mV

0.1 V

—

—

1.0 mV

10.0 mV

0.1 V

—

—

1.0 mV

10.0 mV

0.1 V

—

10


111



10


112



Cable Diagrams

Figure 11-1

Standard Ion Gauge Cable (See Figure 1-6 on page 22)

Use pin covers to cover unused pins on the nude gauge.

Figure 11-2

Nude Ion Gauge Cable



113

Cable Diagrams

Figure 11-3

Varian 564 Ion Gauge Cable

114

Figure 11-4

Ion Gauge Cable Cross Section



Cable Diagrams

Figure 11-5

Convectron Gauge Cable

Figure 11-6

Thermocouple Gauge Cable



115

Cable Diagrams

Figure 11-7

Capacitance Manometer Module Cable

116



Cable Diagrams

Figure 11-8

Overlay Top Cover.



117

NOTES

118



Index

A

analog output

66

Convectron gauge module

59

Convectron/Capacitance manometer module

103

Convectron/Capacitance manometer module fullscale adjust

104

ion gauge electrometer module

40

Thermocouple gauge module

66

B

baud rate

RS-232 interface module

79

bus structure

30

byte format, RS-232 interface module

79

C

cable collector cable routing, illustration

23

connections

23

connections, illustration

23

Convectron/Capacitance manometer module installation

102

ion gauge cross section, illustration

114

Linear analog output module connection

108

nude ion gauge, illustration

113

standard ion gauge, illustration

22

,

113

Varian 564 ion gauge, illustration

114

Cable Diagrams

Capacitance Manometer

116

Controller

117

Convectron Gauge

115

nude ion gauge cable

113

Standard Ion Gauge

113

Thermocouple

115

Varian Ion Gauge

114

calibration


60


102

,

104

general

30


42

Linear analog output module

109


68

capacitance manometer module

16

cable, illustration

116

certification, product

12

character framing


80

cleaning

Convectron gauge module gauge tube

61

command syntax

IEEE-488 module

96


81

computer interface

35

example

35

,

36

configuration capacitance manometer module

16


15

IEEE-488 computer interface module

16

ion gauge (IG) electrometer module

15

process control module

16

remote input/output module

15

RS-232 computer interface module

16

RS-485 computer interface module

16

Thermocouple gauge (TC) module

16

connections, cable

23

control board, illustration

33

control unit front panel, illustration

27

Convectron cable, illustration

115


15

1/8 NPT mount

50

analog output

59

calibration

60

cleaning gauge tube

61

description

47

display update rate switch

47

filament auto turn-on

60

front panel, illustration

60

gauge tube orientation

49

illustration, indicated vs. true pressure curve

53

–

58

indicated vs. true pressure curves

51

installation

47

installation, precautions

48

maintenance

60

mounting illustration

49

NW16KF flange mount

50

operation

50

pressure analog output

59

reading pressure

50

rear panel illustration

59

safety instructions

45

specifications

64

theory of operation

62

top view illustration

47

,

63

transducer test procedure

63

troubleshooting

63

,

64

tube installation

48

using below 10

-3

Torr

50

using with gases other than N

2 and air

51

Convectron gauge module front panel

60

Convectron/Capacitance manometer module analog output

103

analog output full-scale adjust

104

cable illustration

103

cable installation

102

calibration

104

description

101


102

front panel illustration

102

full-scale adjust

105

installation

101

operation

103

,

105

range switch

102

reading pressure

103


103

specifications

106


101

,

104

troubleshooting

105

units of measure

101

vacuum calibration

102

D

degas ion gauge electrometer module power adjustment

40

on/off

28

dip switches


79

,

95

,

99

display

Index-119



Index

printed circuit board, illustration

19

Process control module

72

single digit, installation

19



47


102


38


65

E

electrometer output

Linear analog output module IG

111

emission adjustment ion gauge electrometer module

39

emission range ion gauge electrometer module

39

error messages

IEEE-488 module

98


83

examples

Convectron gauge module, indicated/true pressure

52

display pressure

35

extended capability VGC

35

F

fault indication

32



60


67

filament current limit

30

front panel control unit, illustration

27

Convectron gauge module, illustration

60

Convectron/Capacitance manometer module, illustration

102

electrometer module, illustration

38

Linear analog output module, illustration

107

Process control module, illustration

73

Thermocouple gauge module, illustration

67

full-scale adjust


105

Linear analog output module IG

109

Linear analog output module TC

109

G

gauge tube orientation


49

grid bias potential adjustment

30

voltage adjustment, illustration

30

ground test

10

,

24

H

handshake line control switches, RS-

232 interface module

80

I

IEEE-488 module command syntax

96

computer interface option

16

description

95

error messages

98

installation

95

interface bus address

95

operation

96

specifications

99

SRQ mode

96

talk-only mode

96


95

,

99

troubleshooting

99

IG zero adjust


109

illustration

307 overlay top cover

117

cable connections

23

cable for Varian 564 ion gauge

114

capacitance manometer module cable

116

collector cable routing

23

control board

33

control unit front panel

27

Convectron cable

115

Convectron gauge module mounting

49

Convectron gauge module rear panel

59

Convectron gauge module schematic

62

Convectron gauge module top view

47

,

63

Convectron gauge module, indicated vs. true pressure curve

53

–

58

Index-120



Convectron/Capacitance manometer module cable

103

Convectron/Capacitance manometer module front panel

102

Convectron/Capacitance manometer module rear panel

103

Convectron/Capacitance manometer module top view

101

,

104

correct system grounding

26

grid voltage adjustment

30

IEEE-488 module top view

95

,

99

ion gauge cable cross section

114

ion gauge electrometer module back panel

40

ion gauge electrometer module, front panel

38

ion gauge electrometer module, top view

37

ion gauge schematic

29

line voltage select jumpers, power supply PC board

17

Linear analog output module front panel

107

Linear analog output module top view

107

module positions

18

mounting methods

21

nude ion gauge cable

113

power supply rear panel

33

printed circuit board

19

Process control module front panel

73

Process control module pin assignments

72

Process control module relay contacts status

75

Process control module relay status lights

72

Process control module top view

74

remote control connector

29

remote input/output option

19

RS-232 interface module top view

80

,

85

standard ion gauge cable

22

,

113

thermocouple gauge cable

115

Thermocouple gauge module front panel

67

Thermocouple gauge module pressure analog output

67

Index

Thermocouple gauge module rear panel

66

Thermocouple gauge module top view

65

,

69

installation

19

307 VGC control unit

17


47

,

48

Convectron gauge module gauge tube orientation

49

Convectron gauge module precautions

48


101

Convectron/Capacitance manometer module cable

102

display, single digit

19

IEEE-488 module

95


37

ionization gauge types

22

line voltage selection

17


107

module

17

mounting configuration

20

mounting methods, illustration

21


71


19


79

single digit display

19


65

Thermocouple gauge module tube

66

interface bus address

IEEE-488 module

95

invert RTS switch, RS-232 interface module

81

ion gauge assignment, Process control module

74

cable cross section, illustration

114

configuration

15

on/off

27

schematic, illustration

29

theory of operation

29

ion gauge electrometer module analog output

40

back panel illustration

40

calibration

42

degas on/off

38

degas power adjustment

40


38

emission adjustment

39

emission range

39


38

installation

37

on/off

38

operation

38

pressure analog output

41

relative gas sensitivities

39

,

40

sensitivity adjustment

39

specifications

44


37

troubleshooting

43

units of measure

37

ionization gauge types installation

22

L

line voltage select jumpers, power supply PC board, illustration

17

selection

17

Linear analog output module cable connection

108

calibration

109

description

107

electrometer (IG) output

111

electrometer (IG) range selection

107


107

IG full scale adjust

109

IG zero adjust

109

installation

107

operation

108

pin assignments

108

specifications

110

TC full scale adjust

109

TC zero adjust

109

theory of operation

109

thermocouple output

110


107

troubleshooting

110

M

maintenance


60

microcontroller

30

module calibration

30

installation

17

positions, illustration

18

mounting configuration

20

mounts

1/8 NPT

50

NW16KF

50

N

NW16KF flange mount


50

O

1/8 NPT mount


50

on/off degas

28


38

toggle key

27

operation

307 VGC Control unit

27


50


103

,

105

IEEE-488 module

96


38


108

Linear analog output module theory

109


72

Process control module theory

77

RS-232 interface module theory

84

theory of 307 VGC control unit

29

theory of Convectron gauge module

62


66

P

pin assignments

28


108

power on/off toggle key

27

power supply

307 VGC control unit configuration

15

rear panel, illustration

33

pressure

Convectron gauge module, analog output

59

Convectron gauge module, indicated vs. true curves

51

Convectron/Capacitance manometer module, reading

103

reading, Convectron gauge module

50

Thermocouple gauge module, reading

66

pressure analog output ion gauge electrometer module

41

process control additional

35

Process control module description

71


73

installation

71

ion gauge assignment

74

operation

72

Index-121



Index

option

16

pin assignments illustration

72

relay contacts status illustration

75

relay polarity setting

74

relay status lights illustration

72

setpoint display

72

specifications

77

theory of operation

77


74

troubleshooting

77

R

range selection


107

range switch


102

relative gas sensitivities ion gauge electrometer module

39

,

40

relay contacts status, Process control module

75

Relay polarity setting

88

relay polarity setting


74

relay status lights, Process control module

72

remote control connector, illustration

29

remote input/output option, illustration

19


15

,

19

pin assignments

28

repair order

33

Return Material Authorization (RMA)

12

RS

89

RS-232 interface module baud rate

79

byte format

79

character framing

80

command syntax

81

description

79

dip switches

79

,

95

,

99

error messages

83

handshake line control switches

80

installation

79

invert RTS switch

81

option

16

specifications

86

talk-only mode

80

theory of operation

84


80

,

85

troubleshooting

85

RS-485

Address

87

Byte Format

88

Character Framing

88

Character framing switch settings

88

Command Syntax

92

Connecting the Interface

89

Connectors

90

Factory Defaults

87

Installation

87

Introduction

87

Preparing for Use

91

Response Delay

88

Specifications

90

Troubleshooting

94

RS-485 Address

87

RS-485 interface module option

16

S

safety

Convectron gauge module instructions

45

instructions

9

sensitivity adjustment ion gauge electrometer module

39

service guidelines

12

setpoint display


72

single digit display installation

19

specifications


34


64


106

IEEE-488 module

99


44


110


77


86


70

SRQ mode

IEEE-488 module

96

standard ion gauge cable, illustration

22

,

113

system ground

10

system ground test procedure

24

system grounding, illustration

26

T

307 VGC control unit configurations

15

description

15

installation

17

mounting configurations

20

operation

27

overlay top cover, illustration

117

power supply module

15

specifications

34

troubleshooting

31

units of measure

27

talk-only mode

IEEE-488 module

96


80

TC zero adjust


109

theory of operation


29


62

ion gauge

29


77

thermocouple gauge cable, illustration

115


66

calibration

68

description

65


65


67


67

installation

65

operation

66

option

16

pressure analog output illustration

67

reading pressure

66


66

specifications

70


65

,

69

troubleshooting

69

tube installation

66

units of measure

65

thermocouple output


110

transducer test procedure, Convectron gauge module

63

Troubleshooting

RS-485

94

troubleshooting basic 307 VGC

31


63

,

64


105

fault indication

32

IEEE-488 module

99


43


110

Index-122




77


85


69

U

units of measure


27


101


37


65

W

warranty

13

Index



Index-123

Index

Index-124





Series 307



6450 Dry Creek Parkway

Longmont, CO USA 80503

Phone: 1-303–652–4400

15 Elizabeth Drive

Chelmsford, MA USA

Phone:

01824

1-978–262–2400

Worldwide Customer Service/Support - 24/7

Phone: 1-800-367-4887

To obtain a copy of this instruction manual online, visit our website at

www.brooks.com

(Adobe

®

Reader

®

version 5.0 or higher required)

© 1986-2008 Brooks Automation, Inc.

Instruction Manual

Instruction manual part number 307024

Revision A - August 2011

Granville-Phillips 307 Series 307 Vacuum Measurement Controller Instruction Manual

Assistant Bot

Series 307

Instruction Manual

Series 307

Instruction Manual

Series 307 Vacuum Gauge Controller Part Numbers

Table of Contents

Safety Instructions

NOTE: These instructions do not and cannot provide for every contingency that may arise in connection with the installation, operation, or maintenance of this product. If you require further assistance, contact Granville-Phillips at the address on the title page of this manual.

Service Guidelines

Damage Requiring Service

Extended Warranty

Certification

FCC Verification

Chapter 1

The Series 307 Vacuum Gauge Controller

1.1 General Description

1.2 Available Configurations

1.2.1 Power Supply Module

1.2.2 Ion Gauge (IG) Electrometer Module

1.2.3 Remote Input/Output Module

1.2.4 Convectron Gauge (CG) Module

1.2.5 Thermocouple Gauge (TC) Module

1.2.6 Process Control Module

1.2.7 RS-232 Computer Interface Module

1.2.8 RS-485 Computer Interface Module

1.2.9 IEEE-488 Computer Interface Module

1.2.10 Capacitance Manometer Module

1.3 Installation

1.3.1 Line Voltage Selection

1.3.2 Module Installation

1.3.3 Mounting Configurations

1.3.4 Ionization Gauge Types and Installation

1.3.5 Cable Connections

1.3.6 System Ground Test Procedure

1.3.7 Grounding the System

1.4 Operation

1.4.1 Summary of Controls and Indicators

1.4.2 Units of Measure

1.4.3 Ion Gauge On/Off

1.4.4 Degas On/Off

1.4.5 Remote Input/Output Option

Pin No. Function

Pin No. Function

1.5 Theory of Operation

1.5.1 Ion Gauge Theory

1.5.2 Microcontrollers and Bus Structure

1.6 Calibration

1.7 Troubleshooting, Basic 307 Vacuum Gauge Controller

1.7.1 Guidelines

1.7.2 Fault Indications

Symptom Possible Cause

1.7.3 Repair Ordering

NOTE: Under no circumstances will Brooks Automation, Inc./Granville-Phillips be liable for shipping damages due to rough handling, improper packaging, or other circumstances beyond its control.

1.8 Specifications

1.9 307 Extended Capability Vacuum Gauge Controller

1.9.1 Gauges

1.9.2 Process Control (C, D and E)

1.9.3 Computer Interface

Chapter 2

The Ion Gauge Electrometer Module

2.1 Introduction

2.2 Installation

2.2.1 Units of Measure

2.3 Operation

2.3.1 Ion Gauge On/Off and Degas On/Off

NOTE: Changing the emission range by one decade will also change the overpressure shutdown

point by one decade. See Section 2.4 on page 42 for details of the overpressure shutdown

adjustment. Adjustment of emission within a range (see below) will not affect the overpressure shutdown point.

2.3.2 Relative Gas Sensitivities

Gas

Rx

Gas

Rx

2.4 Electrometer Calibration

2.5 Electrometer Troubleshooting

Symptom

Possible Cause

2.6 Electrometer Module Specifications