Operation. Orolia GPS Ageless Master Oscillator 8194B, 8195B, 8197B

Add to My manuals
138 Pages

advertisement

Operation. Orolia  GPS Ageless Master Oscillator 8194B, 8195B, 8197B  | Manualzz

Spectracom Corporation 8194B, 8195B, 8197B

3 Operation

3.1 Introduction

This section describes the front and rear panel functions, and operational information for the Spectracom GPS Ageless Master Oscillator.

3.2 Front Panel Functions

The front panel (with the battery option) is shown in Figure 3-1. The paragraphs below describe the indicators and connectors found on the front panel.

Power

This green lamp indicates that the unit is connected to the primary power source and is turned on.

Tracking GPS

During initial operation the TRACKING GPS lamp turns on when the receiver has tracked at least four qualified satellites for one minute. The lamp turns off when fewer than four qualified satellites are tracked and Alarm Timeout 1, AT1, expires. The lamp turns back on when at least four satellites are reacquired and qualified for one minute.

Oscillator Locked

The green OSC LOCKED lamp is off during start-up. The lamp turns on when the standard oscillator is phase locked to the GPS reference. Entering a new frequency offset, an Alarm Timeout 2 (AT2) or Frequency alarm turns this lamp off until oscillator phase lock is achieved.

The Master Oscillator divides alarm conditions into two categories, Major and Minor. A

Major Alarm is asserted when fault conditions exist which affect the operation or accuracy of the unit. A Minor Alarm warns of conditions having no immediate effect on total operation, but may require corrective action.

Major and Minor Alarm conditions are communicated by the front panel lamps and relay contacts on the rear panel Alarm Output connector. In addition Major alarm relay contacts are found on the 1544 kHz, 2048 kHz, Data Clock and Data Sync output connectors. Alarm status may also be monitored using the front panel RS-232 or rear panel RS-485 communication ports. Refer to Section 4 for a complete listing of alarm status and alarm clearing commands.

GPS Ageless Master Oscillator Instruction Manual

3-1

8194B, 8195B, 8197B Spectracom Corporation

This lamp turns on when any of the Major Alarm condition is present. The lamp turns off when the fault condition is corrected. A Major Alarm is asserted when the following conditions exist:

Frequency Error:

Measured oscillator frequency error exceeds1 x 10

-8

or whenever an AT2 Alarm is asserted. A frequency alarm is also asserted during start-up.

GPS Tracking Timeout 2:

The period of time (AT2) allotted for operation without tracking a minimum of four qualified satellites has expired. Factory default period is 2.5 hours. An AT2 Alarm is also asserted during start-up.

GPS Tracking Timeout 3:

The period of time (AT3) allotted for operation without tracking a minimum of four qualified satellites has expired. Factory default period is 30 days. An AT3 Alarm is also asserted during start-up.

CPU Fault:

The CPU is unable to communicate with the GPS receiver.

Test Mode:

Unit has been placed in TEST MODE operation.

Free Run:

While in Test Mode, the automatic frequency control feature has been disabled.

Short Gate:

While in Test Mode, gate time has been configured for 10 seconds, measurement resolution is reduced.

3.2.2.2 Minor Alarm Lamp

This lamp turns on whenever a Minor Alarm condition is present. The lamp turns off when the fault condition is corrected. A Minor Alarm is asserted when:

Output Fault:

No output is detected from one or more of the four rear panel frequency outputs. A shorted cable could cause the fault, reflections due to an un-terminated cable or Signature Control removed the outputs.

Oscillator Adjust:

Warns that oscillator is operating within 10% of the minimum or maximum control setting. The oscillator requires manual adjustment. Refer to

Section 6, Service Information, for the oscillator adjustment procedure.

GPS Tracking Timeout 1:

The period of time (AT1) allotted for operation without tracking a minimum of four qualified satellites has expired. Factory default =1.0 minute. An AT1 Alarm is also asserted during start-up.

3-2

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

Figure 3-1 Spectracom Master Oscillator Front Panel

GPS Ageless Master Oscillator Instruction Manual

3-3

8194B, 8195B, 8197B Spectracom Corporation

Low Quality Alarm:

Warns of low GPS signal quality. The alarm is asserted whenever the "Q" value in the Tracking Histogram is below 3000.

Replace Battery:

Internal battery pack, Option 02 only, has failed daily test, needs replacement. Refer to Section 6, Service Information, for battery replacement instructions.

Frequency Offset:

A new simulcast offset value is entered. The alarm remains active until the standard oscillator has corrected for the offset.

Antenna Problem:

Antenna sense circuitry warns when the antenna is not connected or a cable short or open is detected. It warns when the antenna power supply is under or over current. This alarm may also be asserted when the receiver is connected to an antenna splitter device that does not have a simulated load.

Test Mode:

Unit is placed in Test Mode operation.

3.2.3 Battery Lamps (Option 02 only)

These lamps monitor the status of the optional internal battery backup. Refer to Section

5, Options and Accessories, for additional battery information.

Ready Lamp

This green lamp is on when the battery is OK and fully charged.

Charging Lamp

This yellow lamp is on when the battery is charging.

Replace Lamp

This red lamp turns on and a Minor Alarm asserted when the battery has failed its daily test. The battery must be replaced; refer to Section 6, Service

Information. Refer to the Options and Accessories section for details on the battery daily test.

This is the RS-232 serial communication port. Commands to configure selectable parameters, output operational status and events, and Test Mode functions are entered here. Refer to Section 4.3 for a complete description of the RS-232 commands and responses.

The RS-232 COM connector is a 9-pin series D female. Connector pin numbering is shown in Figure 3-2. Pin assignments are listed in Table 3-1.

The RS-232 Com port transmits and receives ASCII characters at 9600 baud structured as 1 start, 8 data, 1 stop, no parity and xon / xoff flow control.

3-4

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

Figure 3-2 RS-232 Com Pin Numbering

PIN SIGNAL I/O DESCRIPTION

6

7

8

DSR

RTS

CTS

O

*

*

Data Set Ready

Request to Send

Clear to Send

* Pins 7 and 8 are connected together internally.

Table 3-1 RS-232 Com Pin Assignments

The RS-232 Com port is configured as data communication equipment (DCE). Data is output on Pin 2, RXD and commands are input on Pin 3, TXD. When interfacing to data terminal equipment, DTE, (i.e. a personal computer) a one-to-one cable is used.

Interfacing to a DCE requires reversing Pins 2 and 3 or a null modem connection. The

RS-232 COM port does not require hardware handshaking. The Request to Send and

Clear to Send signals are internally connected together, and the DSR signal are held high through a pull-up resistor.

This BNC connector outputs a 10 MHz sine wave signal derived from the disciplined oscillator. The 10 MHz output can be user-configured for simulcast operation. Refer to the Frequency Offset command, 1F0, found in Section 4.3 for additional information.

This output is changed to 12.8 MHz when equipped with Option 06, and 5 MHz with

Option 07 units.

This BNC connector outputs a one pulse-per-second TTL-compatible signal. The signal is derived from the GPS disciplined 10 MHz oscillator. The leading edge of the signal is the on time point adjusted by any cable or offset delays that have been userconfigured. Refer to the Antenna Cable Delay command, ACD, and the One PPS

Offset command, 1PO, descriptions found in Section 4.3 for additional information.

GPS Ageless Master Oscillator Instruction Manual

3-5

8194B, 8195B, 8197B Spectracom Corporation

3.3 Rear Panel Functions

The Model 8195B and 8197B rear panel is shown in Figure 3-3. The Model 8194B rear panel is shown in Figure 3-4. The following paragraphs describe each of the rear panel functions that are available for the Spectracom Master Oscillator Family. Note that the

Model 8194B does not have all of the rear panel functions. Refer to the Product

Comparison Chart for details on the different features and options that are available for each model in the Spectracom Master Oscillator family. The Product Comparison Chart can be found in Section 1.2.

This type N connector is the antenna input to the GPS receiver. The Model 8225 GPS

Antenna and the Model 8227 Inline Preamplifier receive operational power, +5 VDC, from this connector.

The Frequency Outputs are derived from the GPS disciplined oscillator. Four BNC outputs at 10.0 MHz are provided. The signal is a 750 mV rms sine wave into a 50ohm load. The harmonic suppression is 30 dB.

The Frequency Outputs may be placed under signature control. Signature Control removes the outputs whenever a Major Alarm occurs. The outputs return when the fault condition is cleared. The unit is shipped with this feature disabled. The Signature

Control feature may be enabled using the front panel RS-232 Com port. Refer to the

Signature Control command, SC, found in Section 4, Software Commands.

In simulcast radio systems, it is desirable to cover large geographic areas with multiple base station transmitters. Simulcasting requires precise control of transmitter frequencies to reduce interference between adjacent transmitters on the same channel.

Ineffective transmitter frequency control can reduce system coverage and cause "dead spots," "false pages," and message distortion. These adverse effects are reduced or eliminated by providing a carrier frequency offset between adjacent transmitters. The offset values are selected to minimize co-channel interference. To assure maximum performance of the system, periodically checking and adjusting the transmitter oscillators to maintain the desired frequency offsets must neutralize the effects of transmitter oscillator “aging”.

3-6

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

Figure 3-3 Spectracom Master Oscillator Model 8195B and 8197B Rear Panel

GPS Ageless Master Oscillator Instruction Manual

3-7

8194B, 8195B, 8197B Spectracom Corporation

3-8

Figure 3-4 Spectracom Master Oscillator Model 8194B Rear Panel

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

The Spectracom Master Oscillator Simulcast Transmitter Offset provides an accurate, controlled frequency reference that is continuously "frequency locked" to GPS. This reference can be used by synthesized transmitters to provide "ageless" frequency control, including offsets, at an accuracy of ±1.0 x 10

-10

.

The simulcast offsets are divided into two groups; Simulcast 1 (SC1) and Simulcast 2

(SC2). Simulcast 1 has offset steps sized for UHF as listed in

Table 3-2. Simulcast 2 has offset steps sized for VHF Hi as listed in Table 3-3. Within each group exist four positive offset steps and the complimentary negative offset steps.

The simulcast offsets are selected using software commands. Refer to the 10 MHz

Offset command, 1F0, found in Section 4 for additional information.

Offset Name

Offset

Δf

s

Output Frequency Offset @ 450 MHz

SC1 + 1 +1.1E-9 10,000,000.011 Hz +0.5 Hz

SC1 + 2

SC1 + 3

SC1 + 4

SC1 - 1

SC1 - 2

SC1 - 3

SC1 - 4

Offset Name

+2.2E-9

+3.3E-9

+4.4E-9

-1.1E-9

-2.2E-9

-3.3E-9

10,000,000.022 Hz

10,000,000.033 Hz

10,000,000.044 Hz

9,999,999.989 Hz

9,999,999.978 Hz

9,999,999.967 Hz

+1.0 Hz

+1.5 Hz

+2.0 Hz

-0.5 Hz

-1.0 Hz

-1.5 Hz

-4.4E-9 9,999,999.956 Hz -2.0 Hz

Table 3-2 UHF Simulcast Offsets

Offset

Δf

s

Output Frequency

+2.0E-8 10,000,000.200 Hz

Offset @ 150 MHz

+3.0 Hz

+3.4E-8 10,000,000.340 Hz +5.0 Hz

SC2 + 1

SC2 + 2

SC2 + 3

SC2 + 4

SC2 - 1

SC2 - 2

SC2 - 3

SC2 - 4

+4.7E-8

+6.0E-8

-2.0E-8

-3.4E-8

-4.7E-8

10,000,000.470 Hz

10,000,000.600 Hz

9,999,999.800 Hz

9,999,999.660 Hz

9,999,999.530 Hz

-6.0E-8 9,999,999.400 Hz

Table 3-3 VHF HI Simulcast Offsets

+7.0 Hz

+9.0 Hz

-3.0 Hz

-5.0 Hz

-7.0 Hz

-9.0 Hz

GPS Ageless Master Oscillator Instruction Manual

3-9

8194B, 8195B, 8197B Spectracom Corporation

The frequency offset at the carrier frequency is determined by the formula:

Δfc = Fc x Δfs where:

Δfc = carrier offset

Fc = carrier frequency

Δfs = offset of 10 MHz standard (from the tables)

Several output options are available to configure the Frequency Outputs for various applications. The output options are listed below. Refer to Section 5, Options and

Accessories, for a complete description.

• Option 03, Built-in Distribution Amplifier

• Option 06, 12.8 MHz Outputs

• Option 07, 5 MHz Outputs

• Option 16, 1PPS on the third and fourth rear panel frequency outputs

3.3.3 1544 kHz and 2048 kHz Timing Outputs

Each of these RJ-11 receptacles provide an RS-485 Timing Output of the indicated frequency. The output signals, 1544 kHz and 2048 kHz, are synthesized from the 10

MHz GPS disciplined oscillator. Major Alarm relay contacts are included on each output connector.

NOTE:

Simulcast Offsets affects the accuracy of the timing outputs.

The connector pin numbering is shown in Figure 3-5 and pin assignments listed in Table

3-4.

3-10

Figure 3-5 Timing Output Connector

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

PIN SIGNAL

1 + Frequency

NOTES

RS-485 B Terminal

2

3

- Frequency

Ground

RS-485 A Terminal

Cable Shield/Relay Ground

5

6

MAJOR NO

MAJOR NC

Normally Open

Normally Closed

Table 3-4 Timing Output Pin Assignments

NOTE:

A units equipped with Option 06, 12.8 MHz outputs, changes the 2048 kHz output to 1600 kHz.

RS-485 is a balanced differential transmission requiring twisted pair cabling. Refer to

Figure 3-6 for a schematic representation of the RS-485 output driver. Relative to RS-

485 specifications, the A terminal (Pin 2) is negative with respect to the B terminal (Pin

1) for a Binary 1. The A terminal is positive relative to the B terminal for a Binary 0.

Shield

B

A

1

2

3

B Terminal (+)

A Terminal (-)

Figure 3-6 RS-485 Output

The RS-485 output driver can provide a TTL-compatible clock signal when connected in a single-ended configuration. Connect as shown in Figure 3-7 for a TTL clock reference.

The 100-ohm termination resistor is required at the cable destination to prevent ringing and reflections.

GPS Ageless Master Oscillator Instruction Manual

3-11

8194B, 8195B, 8197B Spectracom Corporation

TTL-Compatible

Input

B

1

2

3

N. C.

A

100-ohm

Termination

Resistor

Figure 3-7 Single-Ended Connection

Major Alarm relay contacts are found on Pins 4, 5 and 6 of each timing output connector. During normal operation the Major Alarm relay is energized causing continuity between Pin 4 and Pin 6. When a Major Alarm is asserted the relay is deactivated causing continuity between Pin 4 and Pin 5. The relay remains in alarm condition until the condition causing the alarm is corrected or is reset by the clear alarm,

CA, command. Refer to section 3.2.2.1 for a complete description of Major Alarms.

3.3.4 Data Clock Timing Outputs

This connector provides RS-485 clock signals of one pulse per second (1PPS), 9.6 kHz,

18 kHz and Major Alarm relay contacts. The connector is a 9-pin series D numbered as shown in Figure 3-8. Data Clock pin assignments are listed in Table 3-5.

3-12

Figure 3-8 Data Clock Connector

1

2

3

4

6

7

8

+ 9.6 KHZ

+18 KHZ

+ 1 PPS

RS-485 B TERMINAL

RS-485 B TERMINAL

RS-485 B TERMINAL

MAJOR ALARM GROUND = NORMAL

- 9.6 KHZ

-18 KHZ

- 1 PPS

RS-485 A TERMINAL

RS-485 A TERMINAL

RS-485 A TERMINAL

Table 3-5 Data Clock Pin Assignments

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

The Data Clock timing signals are derived from the 10 MHz GPS disciplined oscillator.

The 1PPS and 9.6 Hz outputs are leading edge synchronized to the GPS 1 PPS output.

Using the 1PPS offset command; 1PO, the outputs can be offset from 0 to 1 second in

0.001 microsecond steps. Refer to Section 4 for additional information on the 1PO

Command. The 18 kHz output is not made leading edge synchronized.

NOTE:

Option 17, replaces the 9.6 kHz and 1PPS signals with the selected CTCSS outputs #3 and #4 respectively

RS-485 is a balanced differential transmission requiring twisted pair cable. Cable lengths up to 4000 feet are possible when using cables specifically designed for RS-485 applications, like Belden 9844 or equivalent. These cables have a braided shield, nominal impedance of 120 ohms, and a capacitance of 12 to 15 picofarads per foot.

Refer to Figure 3-9 for a schematic representation of an RS-485 line driver. Relative to

RS-485 specifications the A Terminal (-) is negative with respect to the B Terminal (+) for a Binary 1. The A Terminal (-) is positive to the B Terminal for a Binary 0.

B

-

+

RS-485 OUTPUT

A

Figure 3-9 RS-485 Line Driver

Major Alarm status can be monitored using Pin 4 of this connector. Under normal operation, Pin 4 is connected to ground. When a Major Alarm is asserted, Pin 4 becomes a high-impedance (open circuit). Refer to Section 3.2.2.1 for a complete description of Major Alarms.

GPS Ageless Master Oscillator Instruction Manual

3-13

8194B, 8195B, 8197B Spectracom Corporation

3.3.5 Set Up Switches

The Set-Up Switches configure the RS-485 address, baud rate and termination.

The Address switches give each unit installed on an RS-485 bus a unique identity. The address may range from 0 – 31, DIP-switches 1 through 5 enter the binary equivalent of the selected address. Table 3-6 lists the RS-485 addresses and the corresponding

DIP-switch settings.

The RS-485 protocol includes address source and destination information.

RS-485

ADDRESS

0

1

2

3

4

5

6

7

DIP SWITCH

1 2 3 4 5

RS-485

ADDRESS

0 0 0 0 0 16

1 0 0 0 0 17

0 1 0 0 0 18

1 1 0 0 0 19

0 0 1 0 0 20

1 0 1 0 0 21

0 1 1 0 0 22

1 1 1 0 0 23

8

9

0 0 0 1 0 24

1 0 0 1 0 25

10 0 1 0 1 0 26

11 1 1 0 1 0 27

12 0 0 1 1 0 28

DIP SWITCH

1 2 3 4 5

0 0 0 0 1

1 0 0 0 1

0 1 0 0 1

1 1 0 0 1

0 0 1 0 1

1 0 1 0 1

0 1 1 0 1

1 1 1 0 1

0 0 0 1 1

1 0 0 1 1

0 1 0 1 1

1 1 0 1 1

0 0 1 1 1

13 1 0 1 1 0 29

14 0 1 1 1 0 30

15 1 1 1 1 0 31

1 = SWITCH ON, 0 = SWITCH OFF

Table 3-6 Address Selection

1 0 1 1 1

0 1 1 1 1

1 1 1 1 1

3.3.5.2 RS-485 Baud Rate

DIP-switch 6 is reserved for future implementation of 19200 baud operation of the RS-

485 COM port. To ensure proper operation, place this switch in the OFF position. This configures the COM port for 9600 baud.

3.3.5.3 Spares

DIP Switches 7, 8, and 9 are reserved for test and future expansion. To ensure proper operation, place these switches in the OFF position.

3-14

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

3.3.5.4 Termination

Switch 10 terminates the RS-485 Receive line with 120 ohms. Place Switch 10 in the

ON position when the unit is installed at the end of the RS-485 bus. Place this switch in the OFF position when the unit is not the last device on the bus.

The RS-485 communication port permits remote configuration control and monitoring of performance and status. The RS-485 Com port uses a protocol and command set described in Section 4.2 of this manual. The Com connector pin numbering is shown in

Figure 3-10. Table 3-7 lists the Com pin assignments.

Figure 3-10 RS458 COM Connector

PIN SIGNAL

1

2

- Transmit

+ Transmit

NOTES

RS-485 A terminal

RS-485 B terminal

3

4

- Receive

+ Receive

RS-485 A terminal

RS-485 B terminal

5 Ground Cable

6 Ground Cable

Table 3-7 RS-485 COM Pin Assignments

The rear panel DIP-switch selects the RS-485 address and termination as described in previous paragraphs. Transmitted characters are in ASCII form with a bit structure of 1 start, 8 data, 1 stop and no parity, data rate is 9600 baud.

RS-485 is a balanced differential transmission requiring twisted pair cable. The RS-485 standard defines the A terminal (-) to be negative with respect to the B terminal (+) for a

Binary 1 (MARK or OFF) state. The A terminal (-) is positive to the B terminal (+) for a

Binary 0 (SPACE or ON) state. Figure 3-11 illustrates the relationship between the A and B terminals for the Transmit and Receive connections.

GPS Ageless Master Oscillator Instruction Manual

3-15

8194B, 8195B, 8197B Spectracom Corporation

TRANSMIT

B

B

RECEIVE

+

-

A

A

Figure 3-11 RS-485 Connection

3.3.7 Data Sync Timing Outputs

This connector provides RS-485 clock signals of 17

2

/

3

Hz, 33

1

/

3

Hz, 18 kHz, 64 kHz and Major Alarm relay contacts. The connector is a 15-Pin series D female numbered as shown in Figure 3-12. Data Sync pin assignments are listed in Table 3-8.

8 7 6 5 4 3 2 1

15 14 13 12 11 10 9

Figure 3-12 Data Sync Connector

3-16

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

PIN SIGNAL DESCRIPTION

1 + 64 kHz RS-485 B Terminal

2

3

4

-64 kHz

+18 kHz

-18 kHz

RS-485 A Terminal

RS-485 B Terminal

RS-485 A Terminal

RS-485 B Terminal

RS-485 A Terminal

RS-485 B Terminal

RS-485 A Terminal

9 Ground Cable

10

11

Major - C

Major - NO

Common Contact

Normally Open

12 Major - NC Normally Closed

13 Ground Cable

14 Ground Cable

15 Ground Cable

Table 3-8 Data Sync Pin Assignments

NOTE:

Option 06, 12.8 MHz outputs, changes the 64 kHz output to 50 kHz.

Option 14, CTCSS Outputs, replaces the 33-1/3 Hz and 17-2/3 Hz signals with the selected CTCSS outputs #1 and #2 respectively.

Refer to Section 5, Options and Accessories, for additional information on

Options 06 and 14.

The 64 kHz and 18 kHz Data Sync outputs are derived from the 10 MHz GPS disciplined oscillator.

The 17

2

/

3

Hz and 33

1

/

3

Hz outputs are derived from the 10 MHz GPS disciplined oscillator and are triggered by the GPS 1PPS output. Using the 1PPS offset command,

1PO, these outputs can be offset from 0 to 1 second in 0.001 microsecond steps. Refer to Section 4 for additional information on the 1PO command. The leading edges of the

17

2

/

3

Hz and 33

1

/

3

Hz outputs are synchronized within ±400 nanoseconds of the Data

Clock 1PPS output.

GPS Ageless Master Oscillator Instruction Manual

3-17

8194B, 8195B, 8197B Spectracom Corporation

RS-485 is a balanced differential transmission requiring twisted pair cable. Cable lengths up to 4000 feet are possible when using cables specifically designed for RS-485 applications, like Belden 9844 or equivalent. These cables have a braided shield, nominal impedance of 120 ohms, and a capacitance of 12 to 15 picofarads per foot.

Refer to Figure 3-13 for a schematic representation of an RS-485 line driver. Relative to RS-485 specifications the A Terminal (-) is negative with respect to the B Terminal (+) for a Binary 1. The A Terminal (-) is positive to the B Terminal for a Binary 0.

B

+

RS-485 OUTPUT

-

A

Figure 3-13 Data Sync Drivers

3.3.8 Major Alarm Contacts

Major Alarm relay contacts are found on Pins 10, 11 and 12 of the Data Sync connector.

A Major Alarm is asserted whenever any of the following alarm conditions exist:

Frequency, Tracking Alarm 2, Tracking Alarm 3, CPU or the unit is placed in Test Mode.

During normal operation the Major Alarm relay is energized. The energized relay causes continuity between the common contact, Pin 10 and the normally open contact,

Pin 11.

A Major Alarm or power failure de-activates the relay causing continuity between common, Pin 10 and normally closed, Pin 12. The relay remains in alarm condition until the fault is corrected or reset by the clear alarm, CA, command.

The Alarm Outputs connector provides relay contact closures for Major and Minor alarms. Relay contacts are rated at 2 Amps, 30 VDC. The mating 7-position terminal block, shown in Figure 3-14, is furnished in the ancillary kit.

3-18

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation

1 2 3 4 5 6 7

8194B, 8195B, 8197B

Figure 3-14 Alarm Outputs Terminal Block

A Major Alarm is asserted when any of the following Alarm conditions exist: Frequency,

Tracking Alarm 2, Tracking Alarm 3, CPU or the unit is placed in Test Mode. During normal operation the Major Alarm relay is energized. The energized relay causes continuity between common contact, Pin 2, and the normally open contact, Pin 3.

A Major Alarm or power failure de-activates the relay causing continuity between common, Pin 2, and the normally closed contact, Pin 1.

A Minor Alarm is asserted when any of the following alarm conditions exist: Output

Fault, Adjust Oscillator, Tracking Alarm 1, Replace Battery, Low GPS Quality, Antenna

Problem, Frequency offset or the unit is placed in Test Mode operation. During normal operation the Minor Alarm relay is de-activated. This causes continuity between common, Pin 5, and the normally closed contact, Pin 6.

When a Minor Alarm is asserted the relay is activated causing continuity between common, Pin 5, and the normally open contact, Pin 4.

Table 3-9 lists the Alarm status and the corresponding contact status. The relay contacts remain in the alarm condition until the fault is corrected. If a minor alarm is caused by a replace battery alarm, it will remain until a Clear Alarm, CA, command is issued.

ALARM STATUS PINS SHORTED* PINS OPEN*

Major Alarm Off 2 , 3 1 , 2

Major Alarm On

Minor Alarm Off

Minor Alarm On

1 , 2

5 , 6

4 , 5

2 , 3

4 , 5

5 , 6

*

Ground is found on Pin 7

Table 3-9 Alarm Operation

GPS Ageless Master Oscillator Instruction Manual

3-19

8194B, 8195B, 8197B Spectracom Corporation

3.3.10 DC Power

The DC Power connector provides primary or backup power to the unit

On AC powered units, the DC power connector allows connection of a backup power source. The backup source powers the oscillator and GPS receiver module whenever

AC power is interrupted. Backup power speeds recovery time when AC power is restored by eliminating oscillator warm-up and retrace and GPS reacquisition time. The backup power source must be +24 VDC, non-ground isolated supply of 10 Watts maximum. When connecting the backup power source, connect a wire jumper from the negative (-) pin to the ground (G) pin as shown in Figure 3-15. The DC power connector is shown in Figure 3-16.

BACKUP POWER SOURCE

+24 VDC

PRIMARY

SOURCE

GROUND

DC POWER CONNECTOR

1

2

+

+24 VDC

SECONDARY

SOURCE

GROUND

3

4

5

G

+

6

G

Figure 3-15 DC Backup Wiring

DC power options allow operation from alternate power sources. Table 3-10 lists the various DC power configurations available. Power is 20 Watts for Model 8195B and 60

Watts for Model 8197B.

Power

Option

Option 52

Option 53

Option 54

Nominal Input Range Fuse

Voltage

± 12 VDC 11.1 - 16.5 VDC 10.0 A

± 24 VDC 22.1 - 33.1 VDC 6.25 A Slo-Blo

± 48 VDC 44.2 - 66.2 VDC 3.0 A Slo-Blo

Table 3-10 DC Power Configurations

Connect the DC power inputs to the 6-position terminal block as shown in Figure 3-16,

DC Power Connector. The mating connector is included in the ancillary kit. Redundant power sources may be connected for improved system reliability. Be certain to observe the polarity markings when connecting power.

3-20

GPS Ageless Master Oscillator Instruction Manual

Spectracom Corporation 8194B, 8195B, 8197B

DC power options, 52, 53, and 54, have isolated inputs, which permits operation from a positive or negative power source. To reduce RFI/EMI emissions use a shielded power cable. Connect the cable shield to the chassis ground pin labeled “G”.

NOTE:

Place the DC power switch in the OFF position prior to connecting DC power.

+ - G + - G

Figure 3-16 DC Power Connector

3.3.11 AC Power

The standard Master Oscillator receives primary power from a 90 to 264 VAC 50/60 Hz power source. A detachable line cord is furnished in the ancillary kit. The supplied line cord is compatible with AC receptacles (NEMA 5 - 15R) commonly found in the United

States and Canada. Alternate type line cords may be obtained locally. Connect the line cord to the rear panel AC module and a properly grounded power receptacle.

The AC power module is equipped with a power switch, line voltage selector, EMI filtering, and a fuse. Figure 3-17, AC Power Module, illustrates fuse replacement. The

AC fuse requires a 1.5 Amp, 250V Slo-Blo fuse. A spare is found in the ancillary kit.

NOTE:

The unit accepts the complete range of 90-264 VAC without a change in instrument setup. Do not change the AC fuse value or line voltage selector.

The ‘115’ label must appear in the cover cutout.

GPS Ageless Master Oscillator Instruction Manual

3-21

8194B, 8195B, 8197B Spectracom Corporation

Figure 3-17 AC Power Module

3.3.12 Cooling fan

Cooling fan operation is microprocessor controlled. The fan is turned on when the internal temperature measures 50°C and off when the temperature reaches 30°C.

3.3.13 Chassis Ground

The chassis ground lug allows the unit’s chassis to be connected to an earth ground in addition to the power line safety ground. Connecting the chassis to a single point ground system may be required in some installations to ensure optimum lightning protection. A separate earth ground is also recommended in installations where excessive noise on the power line degrades the unit’s receiver performance.

3.3.14 Battery Disconnect Switch

Depressing this switch removes the backup battery power from the GPS receiver and ovenized oscillator. The Battery Disconnect switch is operational only on units equipped with Option 02 and when AC power is removed. This feature prevents battery discharge when shipping or storing the unit.

NOTE:

The internal battery must be disabled prior to shipment or storage. Failing to disable the battery may result in reduced capacity and shortened battery life.

NOTE:

The Battery Disconnect Switch is populated on all versions of the Model 8195B.

The switch is only operational on units equipped with Option 02.

3-22

GPS Ageless Master Oscillator Instruction Manual

advertisement

Related manuals

Download PDF

advertisement