Vaisala DMP248 Operating Manual

DMP248 Dewpoint

Transmitter

OPERATING

MANUAL

M210492 EN A

J

ULY

2003

PUBLISHED BY

Vaisala Oyj

P.O. Box 26

FIN-00421 Helsinki

Finland

Phone (int.):

Fax:

(+358 9) 894 91

(+358 9) 8949 2227

Visit our Internet pages at http://www.vaisala.com/

© Vaisala 2003

No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder.

The contents are subject to change without prior notice.

_________________________________________________________________________C ONTENTS

Table of contents

CHAPTER 1 GENERAL INFORMATION ....................................................................................................... 1

S AFETY ................................................................................................................................................................ 1

W ARRANTY ......................................................................................................................................................... 1

CHAPTER 2 PRODUCT DESCRIPTION ......................................................................................................... 3

G ENERAL CHARACTERISTICS ............................................................................................................................... 3

T HE OPERATING PRINCIPLE OF THE DMP248....................................................................................................... 4

Use in high pressure ....................................................................................................................................... 6

CHAPTER 3 INSTALLATION........................................................................................................................... 7

S ELECTING THE PLACE OF INSTALLATION ............................................................................................................ 7

M OUNTING THE TRANSMITTER ............................................................................................................................ 7

Mounting; overview....................................................................................................................................... 9

Mounting the probe directly to the process .................................................................................................. 10

Installing the probe through the ball valve assembly ................................................................................... 11

Mounting the probe with a quick connect .................................................................................................... 17

Sample cell................................................................................................................................................... 18

Grounding .................................................................................................................................................... 20

Connections.................................................................................................................................................. 22

Connection to an AC supply ........................................................................................................................ 23

CHAPTER 4 COMMISSIONING..................................................................................................................... 25

S ECURITY LOCK JUMPER .................................................................................................................................... 25

S ELECTING THE ANALOGUE OUTPUTS ................................................................................................................ 26

C ONNECTING THE RS 232C SERIAL BUS ............................................................................................................ 28

CHAPTER 5 COMMANDS............................................................................................................................... 33

C OMMANDS AND SECURITY LOCK JUMPERS ....................................................................................................... 33

LED COMMANDS ............................................................................................................................................... 34

D ISPLAY / KEYPAD COMMANDS ........................................................................................................................... 35

CHAPTER 6 CALIBRATION AND ADJUSTMENT..................................................................................... 55

H UMIDITY CALIBRATION AND ADJUSTMENT ...................................................................................................... 55

Two-point calibration and adjustment adjustment procedure ...................................................................... 56

Using serial commands .............................................................................................................................................56

Using display/keypad commands..............................................................................................................................57

Using LED commands ..............................................................................................................................................58

Humidity calibration table............................................................................................................................ 59

T EMPERATURE CALIBRATION ............................................................................................................................ 59

One point offset correction........................................................................................................................... 59




Two-point temperature calibration and adjustement .................................................................................... 61




C ALIBRATION OF THE ANALOGUE OUTPUTS ....................................................................................................... 63

Using serial commands ................................................................................................................................ 63

Using display/keypad commands................................................................................................................. 63

V AISALA __________________________________________________________________________ I

OPERATING MANUAL _______________________________________________________________

Using LED commands .................................................................................................................................64

CHAPTER 7 MAINTENANCE .........................................................................................................................67

R EFERENCE MEASUREMENTS .............................................................................................................................67

S ELF DIAGNOSTICS ............................................................................................................................................67

T EMPERATURE CHANNEL ADJUSTMENT WITH P T 100 SIMULATORS ...................................................................68

M EASUREMENT OF OUTPUT CURRENTS USING TEST POINTS ...............................................................................70

A DJUSTING THE CONTRAST OF THE DISPLAY ......................................................................................................71

V AISALA S ERVICE C ENTERS ..............................................................................................................................71

CHAPTER 8 TECHNICAL DATA ...................................................................................................................72

M EASURED VARIABLES ......................................................................................................................................72

O UTPUTS ............................................................................................................................................................73

G ENERAL ...........................................................................................................................................................74

E LECTRONICS ....................................................................................................................................................75

S ERIAL INTERFACE MODULES .............................................................................................................................75

E LECTROMAGNETIC COMPATIBILITY .................................................................................................................76

CHAPTER 9 OPTIONS......................................................................................................................................76

CHAPTER 10 SPARE PARTS AND ACCESSORIES ....................................................................................77

APPENDIX 1 SERIAL COMMANDS...............................................................................................................79

APPENDIX 2 POWER SUPPLY MODULE ..................................................................................................101

APPENDIX 3 INSTALLING AND USING THE RS 485/422 SERIAL PORT MODULE.........................105

APPENDIX 4 INSTALLING AND USING THE CURRENT LOOP MODULE........................................115

APPENDIX 5 ERROR MESSAGES................................................................................................................125

APPENDIX 6 WIRING DIAGRAM ................................................................................................................129

APPENDIX 7 ALARM OUTPUT UNIT .........................................................................................................131

APPENDIX 8 PRESSURE CONVERSION CHART.....................................................................................137

P RESSURE CONVERSION CHART ........................................................................................................................137

Multiplication factors ............................................................................................................................................. 137

II ______________________________________________________________________M210492 EN A

C HAPTER 1 _______________________________________________________ G ENERAL I NFORMATION

CHAPTER 1

GENERAL INFORMATION

Safety

Throughout the manual important instructions regarding the safety considerations are focused as follows.

WARNING Warning denotes a hazard. It calls attention to a procedure, practice, condition or the like, which, if not correctly performed or adhered to, could result in injury to or death of personnel.

CAUTION Caution denotes a hazard. It calls attention to a procedure, practice, condition or the like, which, if not correctly performed or adhered to, could result in damage to or destruction of part or all of the product.

NOTE Note highlights important information. It calls attention to an essential procedure, practice, condition or the like.

Warranty

Vaisala issues a guarantee for the material and workmanship of this product under normal operating conditions for one (1) year from the date of delivery. Exceptional operating conditions, damage due to careless handling and misapplication will void the guarantee.

V AISALA __________________________________________________________________________ 1

C HAPTER 2 _______________________________________________________ P RODUCT DESCRIPTION

CHAPTER 2

PRODUCT DESCRIPTION

General characteristics

The DMP248 transmitter is a microprocessor-based instrument for the measurement of dewpoint temperature in low humidities. The transmitter measures other quantities as well: relative humidity, temperature and ppm concentration (dry). When the dewpoint temperature is below 0 °C, the transmitter calculates the frostpoint instead of the dewpoint. The dewpoint output can be scaled freely, for example, dewpoint -40...+20 °C can be set to correspond to 0...1 V.

The DMP248 transmitter has two analogue outputs and can be connected to a serial bus via the RS 232C interface or optionally through an RS 485/422 serial module or a current loop module.

The transmitter can be configured in many ways. It can have either a blank cover or a cover with a local display and keypad with which the user can operate the transmitter. The power supply voltage can be selected from three alternatives (24 VDC/VAC, 115 VAC, 230 VAC).

Two analogue output signals are selected from the measured quantities; the signals can be scaled. The transmitter can be supplied with two, five or ten metre sensor head cable. The alarm output option enables two separate alarms that can be freely set by user.

Options

Alarm output 2 relays 8A/230V SPCO relays

Power supply 24 VDC (VAC) (standard), 115/230 VAC

Serial interface RS 232C (standard), RS 485/422, current loop

Display cover cover with or without local display & keypad

Cable length 0.56, 2, 5 or 10 metres

V AISALA __________________________________________________________________________ 3


The operating principle of the DMP248

The DMP248 transmitter incorporates the DRYCAP ® sensor which is optimized to be used in low humidities but has also an excellent tolerance against condensation. The DRYCAP ® sensor uses an operating principle based on changes in capacitance as its thin polymer film absorbs water molecules together with a combined temperature measurement with a Pt 100 resistive temperature sensor.

The capacitance of the thin polymer film has a direct response proportional to RH, but combined with the temperature signal the response of the DRYCAP ® sensor is rather proportional to Pw (water vapour pressure) or to the dewpoint.

While frostpoints (dewpoints below 0 °C) in principle can be determined by using traditional RH transmitters, it is very difficult considering the required accuracy at the dry end calibration. As relative humidity levels approach zero the accuracy rapidly decreases and the offset soon becomes the largest source of errors when monitoring frostpoints. Therefore, the focus is to minimize the offset

(error at 0% RH) when monitoring the process gas.

For example to monitor a process with a frostpoint of -40 C and a temperature of +20 C translates to a relative humidity of 0.55%. An offset error of -0.2 %RH, which is well within specifications for a normal RH-transmitter, brings the measured RH down to 0.35%. This would bring the calculated frostpoint down to -44 C. Thus seemingly minor offset errors caused by drift or bad calibration translate into unacceptable frostpoint errors when the RH is low.

To solve the accuracy problem the DMP248 transmitter utilizes a patented method that automatically adjusts the dry end measurement in frostpoints. The offset calibration algorithm incorporated into the

DMP248 transmitter uses the fact that the capacitance of a thin film polymer sensor is proportional to RH as seen in formula 1.

RH out

=

RH

0

+

Gain *

Pw

(2-1) where:

RH

0

=output in completely dry state

Pw=water vapor pressure

Pws(T)=temperature dependent water vapor saturation pressure

4______________________________________________________________________M210492 EN A

C HAPTER 2 _______________________________________________________ P RODUCT DESCRIPTION

The function Pws(T) is well known from literature. Thus, it is possible to determine the offset (RH

0

) if measurements are made at two or (preferably) more temperatures assuming a constant Pw during the process.

0.4

0.3

0.2

0.1

0

30°C

20°C

-0.1

-0.2

-0.3

0 0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

1/Pws(T)

F IGURE 2-1 Device output during hypothetical offset calibration cycle.

For example, for a transmitter with a -0.2%RH offset error is made 11 measurements at temperatures 20...30 °C. The frostpoint is assumed to stay constant at -40 °C and that the 'Gain' is nominal 100%.

As the temperature increases the RH drops. Since the response is linear, a straight line is fitted through the data points. The line intercepts the y-axis at RH

0

as shown in F IGURE 2-1 . Now the RH

0 is known and it can be subtracted from the indicated value 0.35% RH to get the correct value of 0.55% RH.

F IGURE 2-2 shows the DRYCAP



sensor as mounted on a DMP248 probehead. Through a combination of the polymer sensor and Pt 100 sensor, the DRYCAP

 will accurately measure the water vapor pressure used in determining low dewpoints.

During auto-calibration the Pt 100 element is used to first heat and then measure the temperature of the sensor while cooling back to ambient temperature.

A complete cycle of auto-calibration takes 60...70 seconds. When the auto-calibration cycle is active, the transmitter locks the output values to those measured prior to auto-calibration.

V AISALA __________________________________________________________________________ 5


F IGURE 2-2 The DRYCAP



sensor mounted on a DMP248 probe.

Note that the auto-calibration takes place only if the DMP248 is used in ambient humidities below 10 %RH (dewpoint below -12

°

C at 20

°

C) and at ambient temperature 0...+80 °C.

Use in high pressure

If the process pressure differs from the normal ambient pressure, the value has to be entered in the transmitter memory to ensure the best possible measurement accuracy. The pressure setting is used for pressure compensation of the DMP248 transmitter. Note that although dewpoint is a pressure dependent parameter, this setting cannot be used for calculating dewpoints in different pressures. The probe should be installed to a place with pressure equal to that of the process in order to ensure the most reliable measurement. For converting pressure units, see Appendix 8.

NOTE The probe can be installed in the process through the ball valve assembly provided that the process pressure is less than 10 bars. This way, the process does not have to be shut down when installing or removing the probe. However, if the probe is not removed from the process as such (e.g. the process is shut down first), the process pressure can be max. 20 bars.

6______________________________________________________________________M210492 EN A

C HAPTER 3 _______________________________________________________________ INSTALLATION

CHAPTER 3

INSTALLATION

Selecting the place of installation

Select a place which gives a true picture of the environment or process; also select a place that is as clean as possible. Air should circulate freely around the sensor.

It is recommended that the sensor head is installed directly in the process through the ball valve assembly. When the ball valve assembly is used, the chamber or the duct does not have to be emptied or shut down for installation or removal of the probe. Install the sensor head transversely against the direction of the process flow.

If the probe head has to be installed aside of the process gas flow or the process is very hot or particularly dirty, the probe can be installed in a “leak-through” position. In this installation, the probe is mounted behind the ball valve assembly and if necessary, a cooling coil and/or a filter can be mounted in between. The flow passes through the sensor head and leaks out through a vent hole in the fitting body enabling a reasonable response time. In hot and dirty processes, a sample system can also be used.

Mounting the transmitter

In F IGURE 3-1 and F IGURE 3-2 , you can see the dimensions of the

DMP248 transmitter:

V AISALA __________________________________________________________________________ 7


104

CL ENT

120

NOTE

ø6.5

65

F IGURE 3-1

133

145

Dimensions of the DMP248 electronics housing (in mm).

1.

Always mount the transmitter housing with the cable bushings pointing downwards to ensure IP65 (NEMA4) rating

2.

Make sure that the connection cable has the right thickness

( ∅ 7...10 mm) and that the cable bushing is carefully tightened.

3.

Pay always special attention to closing the transmitter cover carefully and remember to tighten all four screws.

PROBE

PUSHED

DOWN

ø5.5

178

149 cable length

2, 5 or 10 m

PROBE UP clasp nut fitting body adjustment range120 mm non leaking screw (A)

(factory setting) or leak screw (B)

(included in the package)

31

F

IGURE

3-2

ø13.5

Probe dimensions (in mm).

29

R1/2 ISO 7/1

8 _____________________________________________________________________M210492 EN A


NOTE Take care not to damage the pipe of the probe. If the pipe is damaged, the probe head is less tight and it will not go through the clasp nut.

Mounting; overview

fitting body hex = 24mm tapered thread

R1/2 ISO 7/1 parallel thread

G1/2 ISO 228/1

(BS 2779, JIS B0202)

ø19mm drilling

>10.5mm

>40mm sealing with:

1. LOCTITE® No 542 + activ. No 7649 (t=-55...+150 °C)

2. MEGA-PIPE EXTRA No 7188 (t=-55...+170 °C)

3. PTFE tape (t=-60...+210 °C) NOTE: the tape does not lock

Process or pipe wall the parts together. Therefore, use two fork spanners (hex 24 and

27 mm) for tightening and opening the clasp nut of the probe

F IGURE 3-3 Sealing and thread cutting for the fitting body.

The fitting body can be installed e.g. on standard pipe fittings (G 1/2

ISO 228/1) or on a thread in the process wall. If the wall thickness is less than 10.5 mm, it is recommended to use a welded sleeve (see

F IGURE 3-3 ). Note that the minimum recommended distance of the fitting body and probe head is 40 mm (see F IGURE 3-3 ).

Adjust the probe to a suitable distance according to the type of installation, and tighten the clasp nut first manually. Then, mark the fitting body and the clasp nut and tighten the nut a further 50...60

° with a fork spanner (see F IGURE 3-4 ).

a pen clasp nut fitting body

F IGURE 3-4 Tightening the clasp nut.

60° max.

V AISALA __________________________________________________________________________ 9


NOTE Be careful not to tighten the clasp nut more than 60

°

as this may result in difficulties when trying to open it.

The probe is delivered with non-leaking screw A mounted. For bypass measurements, this screw is removed and replaced with leaking screw B (included) and an O-ring is placed on the groove of the sintered filter prior to installation. Make sure to tighten the screw carefully.

Screw B has a small (0.08 mm) laser-made hole in the middle; the gas or air to be measured passes through the sintered filter and by the sensor, and leaks out through the screw.

Mounting the probe directly to the process

Select a point, which gives a true picture of the process. The transmitter can be installed directly in the process wall, especially if the pressure of the process is 1 bar (atmospheric processes).

process wall recommended adjustment range

25...135 mm welded sleeve (G1/2, Ø 40 mm)

25 mm

Leave at least 25 mm (1 ") of probe head free to enable a faster response time in unpressurized processes non leaking screw

(screw A, factory setting)

F IGURE 3-5 Installing the probe in an atmospheric process.

If the probe is installed in process pipes where the water is likely to collect at the measurement point, take care to install the sensor head so that it will not be immersed in water.

When the probe is installed directly on the process wall or pipe, note that a closing valve may be needed on both sides of the installed probe so that the sensor head can be removed from the process for calibration and maintenance.

10_____________________________________________________________________M210492 EN A


If the sensor head is installed in a pressurized chamber, always make sure that the pressure of the chamber is equalized with the ambient pressure prior to removing the probe.

capped nut

DIN 917-M22x1.5

when the probe is pulled out for maintenance, cap the hole with a capped nut; this way, the process can be open although the probe is not in place sealing welded sleeve

(G1/2) process pipe

Non leaking screw

(screw A) closing valve

(ball valve)

F IGURE 3-6 Installing the sensor head directly on the process pipe.

Installing the probe through the ball valve assembly

The best way to install the sensor head is through the ball valve assembly. Use a 1/2” ball valve assembly with a ball hole of

∅

14 mm or more. In this kind of installation, it is not necessary to empty or shut down the process for installing or removing the sensor head. If the sensor head is installed in a process pipe, please note that the nominal size of the pipe must be at least 1 inch. See F IGURE 3-7 -

F IGURE 3-8 for detailed instructions.

V AISALA _________________________________________________________________________ 11


probe handle non-leaking screw A

>30 mm ball of the ball valve

(hole diameter

at least 14 mm) process pipe / chamber

NOTE

F IGURE 3-7 Installing the sensor head through the DMP248BVS ball valve assembly.

The probe can be installed in the process through the ball valve assembly provided that the process pressure is less than 10 bars. This way, the process does not have to be shut down when installing or removing the probe. However, if the process is shut down before removing the probe, the process pressure can be max. 20 bars.

See F IGURE 3-8 - F IGURE 3-11 for detailed description of installation through the ball valve assembly. This installation is possible provided that the process pressure is less than 10 bars. Note also that if the sensor head is installed in a process pipe, the nominal size of the pipe must be at least 1 inch.

12_____________________________________________________________________M210492 EN A


•

STEP 1: mount the probe with the ball valve assembly closed; tighten the clasp nut manually.

bushing R1/2 cone/G1/2(40 bar) e.g. Camozzi 2520-1/2-1/2

(the bushing serves for moving the probe (sinter) to such a distance from the ball valve that the valve can be closed) ball valve 1/2" (40 bar) e.g. Atlas Copco:BAL-1A 15 (G1/2) clasp nut fitting body

R1/2 cone, sealed

>30 mm bushing

R1/2 cone sealed nipple

R1/2 cone sealed

F IGURE 3-8 Installing the probe through the ball valve assembly; step 1.

V AISALA _________________________________________________________________________ 13


•

STEP 2: open the ball valve assembly.

manual press tool probe pipe ø5.5

handle marking groove

ø14 leak screw (B)

(hex. 1.5 mm) fitting ferrule clasp nut

(hex 27 mm) fitting body

(hex. 24 mm)

O-ring ball of the ball valve

ø13.5

DRYCAP® sensor filter

R1/2 ISO 7/1

F IGURE 3-9 Installing the probe through the ball valve assembly; step 2 (measures in mm).

14_____________________________________________________________________M210492 EN A


STEP 3: push the probe head through the ball valve assembly into the process. If the pressure is high, use a manual press tool. Note that the sensor head must be pushed so deep that the filter is completely inside the process flow.

MANUAL

PRESS TOOL

VALVE OPEN

VALVE CLOSED

FILTER

F IGURE 3-10 Installing the probe through the ball valve assembly; step 3.

For by-pass measurements, the probe is mounted behind the ball valve assembly and non-leaking screw A on the fitting body is replaced with leaking screw B and O-ring is placed on the groove of the sintered filter. Screw B has a small (0.08 mm) laser-made hole in the middle; the gas or air to be measured passes through the sintered filter and by the sensor, and leaks out through the screw. The process pressure reduces in the hole of the screw B. This installation is recommended if the process flow rate is >20 m/s and there is over-pressure in the process.

V AISALA _________________________________________________________________________ 15

OPERATING MANUAL _______________________________________________________________ gas escape channel: use this position for by-pass measurements leak screw (B) O-ring sintered filter

DRYCAP® sensor

NOTE keep the marking groove in sight when using leak screw (B) process pipe or chamber

F

IGURE

3-11 Installing the sensor head for by-pass measurements.

When pushing the probe head through the ball valve assembly, be careful not to break the sintered filter. Open and close the ball valve assembly with the marking groove always in sight. In by-pass measurements, the clasp nut is tightened manually prior to pressing the probe through the valve. When the probe has been pressed through and the valve is open, the nut is tightened 50...60

° with a fork spanner

(hexagon 27 mm).

16 ____________________________________________________________________M210492 EN A


Mounting the probe with a quick connect

The probe can also be installed with a quick-connect, which acts as a closing valve between the process and the probe. The installation can be easily done even in small ducts with standard parts, and the probe is easily removed when necessary. It is necessary for the probe to be installed in the leak-through position for a reasonable response time.

F IGURE 3-12 illustrates an example of using a quick connect with the

DMP248 probe. The chamber can be made of stainless steel AISI 316.

keep the marking groove in sight when using leak screw leak screw leak screw

G1/2

50 mm

G1/8 or G1/4 fitting part of the quickconnect chamber made of hexagonal bar

(hex=27 mm) sealing process pipe bayonet socket

F IGURE 3-12 Installing the probe with a quick-connect.

V AISALA _________________________________________________________________________ 17


Sample cell

It may be necessary to use the sample cell if the process (e.g. a pipe) is too small for the DMP248 sensor head. Furthermore, if the process is very hot (>80 °C) or particularly dirty, the probe is installed in a sample cell behind a cooling coil and/or filter. In this case, the ambient temperature must be at least 10 °C warmer than the process dewpoint in order to avoid condensation in the sample tubing.

40

6 28

6

G1/2

ISO228/1

80

G1/4

ISO

228/1

S

Sample gas inlet use connector

R1/4 ISO 7/1

68

IN view

A - A

OUT

G1/4

F IGURE 3-13

Sample gas outlet use connector R1/4 ISO 7/1

Dimensions (in mm) of the DMP248SC sample cell.

20

25

25

A A for DMP248 probe

22

80 fixing screws

(e.g. M6x60 or 1/4" x 11/4")

40

TOP VIEW

F IGURE 3-14

SIDE VIEW

Fastening to a metal plate (top view) and on a concrete frame (side view)

18_____________________________________________________________________M210492 EN A

C HAPTER 3 _______________________________________________________________ INSTALLATION process pipe 28 6

6

G1/4

ISO

228/1

S metal plate thickness e.g.

3mm (1/8")

AISI 316

68 80

G1/4 screw

FRONT VIEW

F IGURE 3-15 thread M6 or

1/4"-20 UNC metal hose clamp

40

TOP VIEW Dimensions of the metal plate

Fastening to a process pipe with the help of a metal plate

An overpressure in the process is necessary to create a flow through the sample cell. Note that the pressure of the sample cell must not differ from that of the process because dewpoint temperature changes with pressure. In dirty processes, it may be necessary to use a filter between the cooling coil and the sample cell. One more simple way of using the sample cell with user provided accessories is shown in

F IGURE 3-16 . The flow through the sample cell is controlled with the needle valve and the pressure is kept equal to that of the process.

F IGURE 3-16 Installing the probe in high temperatures (an example).

V AISALA _________________________________________________________________________ 19


Grounding

A single electrical cable with a screen and three to ten wires is recommended for power and analogue output/serial bus connections.

The cable diameter should be 7...10 mm.

The screen of the electrical cable must be grounded properly to achieve best possible EMC performance. Recommended cable shield is done in the cable gland as shown.

• remove the brass disks, rubber ring and nut from the transmitter housing

• strip 165 mm of the cable insulation, but leave 25 mm of the braid visible

• slip the nut and rubber ring over the cable insulation

• slip the brass disk that has the bigger hole in it over the braid so that it rests against the cable insulation

• slip the other brass disk over the wires to the middle of the braid flexible wires 0.5 mm²

(AWG 20), stranded wires recommended

3

165

140 braid brass disks

25 rubber ring nut shielding tube braid brass disks cable

D = Ø 7...10 mm

(If the cable diameter is less than 7mm, use a shrinking tube or an adhesive tape)

• push back the braid and press it between the two brass disks to achieve a full 360° grounding; the fold between the disks should have the same diameter as the brass disks

• secure the braid with a shielding tube

20_____________________________________________________________________M210492 EN A


• insert the wires into the transmitter housing through the gland

• tighten the nut

• connect the wires into the screw terminals and fasten a cable tie around the wires

NOTE cable tie transmitter housing gland brass disks rubber ring nut

When the cable is grounded as explained, the metallic parts of the sensor head, the screen of its cable, the transmitter housing and the screen of the signal cable to external system are all connected to each other. After this, the whole system can be grounded from one point only. If the grounding is made via several points (sensor head, transmitter housing, signal cable), make sure that the different groundings are made to the same grounding potential. Otherwise, harmful grounding currents may be generated. If you do the grounding via the transmitter housing, use one serrated lock washer between a mounting screw and the housing; the lock washer breaks the paint on the housing.

V AISALA _________________________________________________________________________ 21


Connections

CH1- and CH2- are connected together internally

+

V mA

+

V mA

-

-

CURRENT/VOLTAGE

OUTPUTS

POWER SUPPLY

(INTERNAL OR

EXTERNAL)

Do not use power supply ground (-) as output signal ground

X 2

X 1

OPENED COVER OF THE DMP248

F IGURE 3-17

Power supply

Output signals

Electrical connections

24 VDC

24 VAC (see Chapter Connection to an AC supply)

0...20 mA

4...20 mA

0...1 V

0...5 V

0...10 V

Power supply ground (-) is connected to the housing with parallel connection of 15 nF capacitor and 300 k

Ω

resistor.

22_____________________________________________________________________M210492 EN A


Connection to an AC supply

The DMP248 transmitter can also be connected to an AC supply without an external rectifier. However, when more than one transmitter is connected for example to one 24 VAC transformer, a common loop is formed and there is an increased risk of a shortcircuit. To avoid this, always use separate floating supply for each transmitter (see F IGURE 3-18 A). However, if several transmitters have to share one transformer, the phase (

∼

) must always be connected to + connector in each transmitter (see F IGURE 3-18 B).

A) NO COMMON LOOP FORMED - RECOMMENDED

DMP248 transmitter Controller

24 VAC

24 VAC

B) COMMON LOOP FORMED - NOT RECOMMENDED!

DMP248 transmitter

Controller

24 VAC

DMP248 transmitter shared common line

F IGURE 3-18

DMP248 transmitter

Connecting the transmitter to an AC supply.

V AISALA _________________________________________________________________________ 23

C HAPTER 4 _____________________________________________________________ COMMISSIONING

CHAPTER 4

COMMISSIONING

When the DMP248 transmitter leaves the factory, its measurement ranges and output signals have already been selected. The user can subsequently change the measurement units between metric and nonmetric and select and scale the output signals with software functions, see Chapter Selecting and scaling the analogue output quantities and

Appendix 1.

Security lock jumper

Before the settings can be changed, the user must first remove the security lock jumper in connector X15 (see F IGURE 4-1 ). The security lock jumper makes it impossible to change the transmitter settings by mistake. The jumper should be removed only for changing the settings and for calibration; the auto-calibration is active only with the jumper connected. When the security lock jumper is connected, some commands cannot be used (see Chapter Commands and security lock jumpers).

X15

CHANGE OF SETTINGS

DISABLED

F IGURE 4-1


Location of the security lock jumper.

V AISALA _________________________________________________________________________ 25


Selecting the analogue outputs

The DMP248 transmitter can be ordered ready with the current or voltage outputs required. If the outputs need to be changed, move the jumpers in connector X15 into positions as shown in F IGURE 4-2 .

CH1 CH2

CURRENT OUTPUTS

0 ... 20 / 4 ... 20 mA

CH1 CH2

VOLTAGE OUTPUTS

0 ... 5 V / 0 ... 10 V

CH1 CH2

VOLTAGE OUTPUTS

0 ... 1 V

CH1 CH2

CH1 0 ... 1 VOLTAGE OUTPUT

CH2 CURRENT OUTPUT

X15


F IGURE 4-2 Selecting the analogue outputs with jumpers.

The software also has to be informed which outputs are in use. This is done either through the serial interface or the menus on local display when in use. The serial command is AMODE and the display/keypad command

"Mode ð Analog outputs ð Mode"

(see Chapter 5 commands ) . If the outputs need to be scaled, see serial

26_____________________________________________________________________M210492 EN A

C HAPTER 4 _____________________________________________________________ COMMISSIONING command ASCL and the display command

"Mode ð Analog outputs ð Scale"

.

All jumpers are used only with the 0...1 V outputs. When other outputs are in use, the spare jumpers are kept in connector X55.

X55 spare jumpers


F IGURE 4-3 Spare jumpers

V AISALA _________________________________________________________________________ 27


Connecting the RS 232C serial bus

RX

GND

TX

NC

X6


F IGURE 4-4 Serial bus connections.

To connect a PC to the DMP248 transmitters via the RS 232C serial bus, one of the following cables is required. The type of cable depends on the terminal and the connector type.

TXD

PC

TERMINAL

D9S

D25S

6

8

2

5

3

7

20

7

8

4

6

2

5

3

D25P

3

7

2

RXD

RXD

RXD

TXD

TXD

TX

GND

RX

TX

GND

RX

DMP248

TX

GND

RX

F IGURE 4-5 Three connection examples.

28_____________________________________________________________________M210492 EN A

C HAPTER 4 _____________________________________________________________ COMMISSIONING

NOTE

When the serial bus has been connected between the PC and the transmitter, the PC is switched on. When using a PC, a terminal emulation programme (e.g. HyperTerminal, Procomm Plus, Datastorm or Windows terminal) is started.

The factory settings for data transfer are:

•

4800 baud

• even parity

•

7 data bits

•

1 stop bit

• full duplex

When the serial bus settings are changed, the transmitter has to be reset before the new settings become effective.

The processor does not allow the following combinations:

• no parity, 7 data bits, 1 stop bit: if this combination is given the

DMP248 programme will change the number of stop bits to 2.

• even or odd parity, 8 data bits, 2 stop bits: if this combination is given the programme changes the number of stop bits to 1.

Refer to the manuals of the PC and the terminal emulation programme when giving serial settings.

The RS 232C screw terminal cannot be used if an RS 485/422 serial module or a current loop module is used. See Appendices 3 and 4 on how to install and operate these modules.

In calibrating or changing the settings of the transmitter, it can be more convenient to use the connector X17, if connector X6 is already in use. This connector, however, transfers only RS 232C signals. If a

RS 485/422 serial port module or a current loop module has been installed, it has to be removed before communicating through the X17 connector.

V AISALA _________________________________________________________________________ 29


RX GND TX

X17

NOTE

F IGURE 4-6 Location and connections of connector X17.

Some PC computers can generate interferences to the measured humidity and temperature values if the transmitter and the PC are connected to different mains outlets. To minimize the possibility of these interferences, always use the same main outlet (same phase of the main electricity) for the PC and the power supply of DMP248. It is always preferable to use the connector X6 instead of the connector

X17 because it is more immune to interferences.

Reverting to factory settings of the serial port

If the serial port settings are not known, no commands can be given via the serial interface. The settings can be reverted to the factory settings by inserting a jumper in connector X16. The jumper must be inserted when the power is on!

X16


F IGURE 4-7 Forcing the serial port settings back to factory settings.

When the jumper is inserted the serial line factory settings become valid, but only temporarily. The transmitter must be given new settings; otherwise, the transmitter uses the old, unknown settings after power-up.

When the new settings have been given, the transmitter must be reset. The jumper must be removed before the

30_____________________________________________________________________M210492 EN A

C HAPTER 4 _____________________________________________________________ COMMISSIONING transmitter is reset; if the jumper is in place when power is turned on, the transmitter does not work.

After jumper insertion the transmitter is in STOP mode, ready to receive commands.

The same method is used when the transmitter is in POLL mode and the user has forgotten its address.

CAUTION Inserting a jumper in any other place in connector X16 voids the guarantee of the transmitter.

V AISALA _________________________________________________________________________ 31

C HAPTER 5 ________________________________________________________________ COMMANDS

CHAPTER 5

COMMANDS

The DMP248 transmitter uses a microprocessor; therefore, its configuration can be set according to the user's needs. This is done through commands, either utilizing the menus on the local display or giving commands through the serial interface (see Appendix 1). Most often, the commands are used to change the settings of the two analogue channels.

A limited range of commands can be given with the three press switches - up, down and enter - inside the transmitter housing. Four

LEDs indicate the command given with the up and down switches.

LED commands can be used to calibrate the transmitter (both humidity and temperature) or to calibrate the analogue outputs.

A full range of commands can be given through the display/keypad or through the RS 232C serial bus. The commands can be used e.g. to select and scale the outputs, to calibrate the humidity and temperature channels as well as the analogue outputs and to set the serial interface.

Commands and security lock jumpers

In order to prevent any tampering with the transmitter settings, the transmitter cannot be calibrated, the analogue outputs set or the analogue output quantities selected or scaled unless the security lock jumper has been disconnected. The commands involved are:

• all LED commands (except DCAL)

• display/keypad commands:

Cali

Mode

ð

ð

RH T

Analog outputs

Analog outputs ð Mode

Scale

V AISALA _________________________________________________________________________ 33


• serial commands:

CRH, CT, FCRH, ACAL; AMODE, ASEL, ASCL

In the following, the description of these functions is preceded with a reminder of the security lock jumper:

Disconnect the security lock jumper!

LED commands

NOTE If the transmitter has a display/keypad cover, the LED commands cannot be used.

UP

DOWN

ENT

LEDs press switches


F IGURE 5-1 Location of press switches and LEDs

Use the up and down switches (marked with arrows on the printed board) to find the desired command code and acknowledge it with the

ENT switch. The command codes are ( l = lit, ¡ = dark):

¡¡¡¡ (0) return to normal state

¡¡¡l (1) relative humidity calibration

¡¡l¡ (2) temperature calibration

¡¡ll

(3) calibration of analogue outputs l¡¡l

(9) forced auto-calibration (one auto-calibration; the security lock jumper must be connected)

34_____________________________________________________________________M210492 EN A


Display/keypad commands

Display mode

In the display mode, the transmitters output measurements on the display; different quantities can be scrolled with the arrow keys. The first line is scrolled with button

σ

and the second line with button

τ

; all selections are stored with ENTER. The selected quantities appear on the display also after power failure. After the reset, the transmitters are always in the display mode.

The display also shows error messages and alarms if they occur.

Command mode

Press the CL key to enter the command mode. The first display is the main menu:

The commands can be scrolled with the arrow keys. The currently active command flashes; a command is selected with the ENT key.

When a menu is displayed, either the first command or the currently valid setting flashes. The CL key takes the transmitter back to the display mode.

Entering numbers

When the transmitter needs numbers to be entered into the programme

(e.g. when scaling or setting the analogue outputs, in calibration or when giving the transmitter an address), the field is either empty or the currently valid figure is displayed. Any previously given value is deleted with the CL key.

When the field is empty, a cursor blinks at the right side of the display. Pressing the arrow keys brings either a blank (), a comma ( , ), a dash ( ), a full stop ( .

) or a number from 0 to 9 on the display. The right character is selected with ENT; after that, the number or numbers move left one step. Entering numbers is ended with selecting a blank

() and pressing ENT. The last character entered can be deleted with

CL. If CL or ENT key is pressed when the field is empty, the program returns to the previous display.

V AISALA _________________________________________________________________________ 35


With some commands (e.g. calibration) the figures are changed using the arrow keys. When an arrow key is pressed continuously for a while, the numbers start changing at an increasing rate.

Auto-calibration

NOTE Normally auto-calibration parameters do not have to be changed.

•

Select

More

in the main menu and then again

More

in the second

More menu. Select

Dry cal

and then

Settings

.

•

The interval parameter defines the frequency of auto-calibration cycles. When the transmitter is turned on, the first auto-calibration takes place after an hour unless the frequency has been set to less than an hour. After the first auto-calibration, the set frequency is activated and the auto-calibration takes place e.g. every six hours.

If the setting is correct, press ENT.

•

If the setting needs to be changed, press CL and change the setting with arrow keys; acknowledge the setting with ENT. If the setting is changed, it becomes valid only after the next auto-calibration has been completed. If you wish to activate it immediately reset the transmitter or turn it off.

•

This parameter defines the maximum allowed change of the dewpoint value during the pre-defined dTdp time

. If the change in dewpoint value exceeds the limit, the calibration is not started. The auto-calibration is done only after process is stabilized. The transmitter retries untill the calibration is succesfully complited.

•


•

If the setting needs to be changed, press CL and change the value with arrow keys; acknowledge the setting with ENT.

36_____________________________________________________________________M210492 EN A


•

This parameter defines the measuring time of the change in dewpoint prior to the auto-calibration (see the parameter

Max dTdp)

.

•


•

If the setting needs to be changed, press CL and change the value with arrow keys. Acknowledge the setting with ENT.

•

This parameter defines the maximum correction (%RH) the transmitter does during each auto-calibration cycle. If the correction exeeds the limit, the calibration is ignored. If the setting is correct, press ENT.

•


NOTE

•

This parameter defines the time the output values prior to the autocalibration are frozen after the calibration. The time is for sensor temperature stabilization.

•


•


Auto-calibration takes place only when the security lock jumper is connected. During auto-calibration, the reading on the display is frozen.

V AISALA _________________________________________________________________________ 37


NOTE If the process pressure differs from the normal ambient pressure, the value has to be entered in the transmitter memory to ensure the best possible measurement accuracy. The pressure setting is used for pressure compensation of the DMP248 transmitter.

Forced auto-calibration

•

Select More in the main menu and then again More in the second

More menu. Select

Dry cal

and then

Calibration

•

Select

More

in the main menu and then again

More

in the second

More menu. Select

Dry cal

and then

Calibration

. The following is displayed:

Calibration...

press any key to abort

•

If you press any key, the calibration is interrupted. If no key is pressed, the calibration takes place immediately. The text above is displayed during the calibration. If the process is unstable (see

Chapter Auto-calibration) or relative humidity is over 10%, the calibration is not performed. The text above is only shortly displayed and the display returns to the measuring mode. The calibration is not performed again even if the maximum correction is exceeded.

Analogue output commands

Selecting the output (mA/V)


•

Select

Mode

in the main menu and

Analog outputs

in the Mode menu:

•

Select

Mode ( mA / V )

. The current settings for channel 1 are displayed:

38_____________________________________________________________________M210492 EN A


•

If the settings are correct, press ENT.

•

If the settings need to be changed, press CL:

− the quantity (mA/V) starts flashing; it can be changed with the arrow keys and acknowledged with the ENT key

− the lower limit starts flashing

− acknowledge the lower limit with ENT or start changing it by pressing CL; a new lower limit is given one character at a time with the arrow keys

− the upper limit starts flashing

− acknowledge the upper limit with ENT or start changing it by pressing CL; a new upper limit is given one character at a time with the arrow keys

When channel 1 has been set, the programme goes on to channel 2; the procedure is the same as with channel 1.

NOTE Also the analogue output jumpers must be set to correct places (see

F IGURE 4-2 )

Selecting and scaling the analogue output quantities


•

Select

Mode


Analog outputs

in the Mode menu:

V AISALA _________________________________________________________________________ 39


•

Select

Scale

. The quantity and scaling for channel 1 are displayed:

•

If the settings are correct, press ENT.

•


− the quantity starts flashing; it can be changed with the arrow keys and acknowledged with the ENT key

− the lower limit starts flashing

− acknowledge the lower limit with ENT or start changing it by pressing CL; a new lower limit is given with the arrow keys

− the upper limit starts flashing

− acknowledge the upper limit with ENT or start changing it by pressing CL; a new upper limit is given with the arrow keys

−

When channel 1 has been set, the programme goes on to channel 2; the procedure is the same as with channel 1.

Output via serial bus

Turning the serial interface echo ON/OFF

Select

More

in the main menu, select

More

in the More menu, then again

More

and then

Echo

.

•

Use the arrow keys to select the right alternative and press ENT.

Serial bus settings

•

Select

Seri

in the main menu; the currently valid serial interface settings are displayed:

40_____________________________________________________________________M210492 EN A


•

If the settings are correct, press ENT; the programme returns to the display mode.

•


• Select the parameter to be changed with the arrow keys and ENT key.

Selecting baud rate:

Selecting parity:

Selecting data bits:

Selecting stop bits:

Full duplex/half duplex:



DMP248 programme will change the number of stop bits to 2

V AISALA _________________________________________________________________________ 41


NOTE

• even or odd parity, 8 data bits, 2 stop bits: if this combination is given the programme changes the number of stop bits to 1

The serial bus settings become effective only after reset.

Setting the transmitter address

Address is used when more than one transmitter is connected to one serial bus; it makes it possible to communicate with one transmitter at a time.

•

Select

More in the main menu and

Addr

in the More menu; the following is displayed:

•

Pressing ENT returns the programme to the main menu.

•

Pressing CL deletes the old address; enter the new address with the arrow keys.

Selecting the output units

•

Select

Unit

in the main menu:

•

Use the arrow keys to select the right alternative and press ENT.

RH

T

Td ppm v metric nonmetric

%RH

°C

°C ppm

%RH

°F

°F ppm

42_____________________________________________________________________M210492 EN A


Output modes

The output modes only affect output through the serial interface: the transmitter accepts all display and LED commands irrespective of which serial output mode it is in. The DMP248 transmitter has three serial output modes: RUN, STOP and POLL.

In the RUN state the transmitter outputs measurements automatically through the serial interface to a PC or a peripheral. The only command that can be given through the serial interface is S (stop) which ends the RUN state.

In the STOP state serial commands are given to the transmitters.

Measurements are then output only by entering command SEND.

The POLL state is used when more than one transmitter is connected to the same serial bus; a single transmitter can be addressed and communicated with. When the connection to the one transmitter is opened in the POLL state, the transmitter goes into STOP state and can then receive commands normally. Closing the connection returns the transmitter to POLL state. In POLL state the transmitter outputs measurement only when requested (with command SEND, see page

51). If the user has forgotten the address of the transmitter and the transmitter does not have a display, the transmitter has to be reverted to the factory settings. If the transmitter has a display, the settings can be checked through it.

Setting the serial interface operation mode

•

Select

Mode

in the main menu; the following is displayed:

•

Select

Serial output

:

•

The currently valid setting flashes. Select the desired mode with the arrow keys and press ENT. After this the programme returns to the Mode Menu.

•

When Run mode is selected, the currently valid output interval is displayed:

V AISALA _________________________________________________________________________ 43


The output interval setting can be changed as follows:

Others

• press CL

• the number starts flashing

• if the interval needs to be changed, press CL again and enter the new interval; otherwise press ENT

• the unit (s, min, h) starts flashing

• the unit can be changed with the arrow keys and acknowledged with ENT

• after this the programme returns to Mode menu

Pressure compensation

The pressure is used for pressure compensation of the DRYCAP

 sensor in order to ensure the best possible measurement accuracy. If the process pressure differs from normal ambient pressure, the value has to be entered in the transmitter memory. The pressure also has a considerable effect on the ppm v

value. The pressure to be entered is the absolute pressure in hPa (for converting pressure units, see

Appendix 8).

• Select

Pres

in the main menu and the following appears:

• Pressing ENT returns the programme to the main menu without changing the pressure reading.

44_____________________________________________________________________M210492 EN A


NOTE

•

If the pressure needs to be changed, press CL; enter the new pressure with the arrow keys

The pressure compensation takes place only with the security lock jumper connected. If the security lock jumper is not connected, the pressure compensation is performed with the value 1013.25 hPa.

Setting the date

•

Select More in the main menu; select Date in the More menu:

•

If the date is correct, acknowledge it by pressing ENT; this takes the programme back to the More menu.

•

If the date needs to be changed, press CL.

− first the centuries (19) start flashing; use the arrow keys to change them and press ENT

− the years (92) start flashing; use the arrow keys to change them and press ENT

− the months (06) start flashing; use the arrow keys to change them and press ENT

− the days (17) start flashing; use the arrow keys to change them and press ENT

Setting the time

•

Select

More

in the main menu; select

Time

in the More menu:

•

If the time is correct, acknowledge it by pressing ENT; this takes the programme back to the More menu.

•

If the time needs to be changed, press CL.

V AISALA _________________________________________________________________________ 45


− first the hours (14) start flashing; use the arrow keys to change them and press ENT

− the minutes (25) start flashing; use the arrow keys to change them and press ENT

− the seconds (32) start flashing; use the arrow keys to change them and press ENT

NOTE The transmitter does not have a real-time clock with backup battery.

This means that the date and time settings are not permanent.

Serial commands

More detailed descriptions of the serial commands can be found in

Appendix 1. Here only the most commonly used command sequences are described. The instructions on how to connect the DMP248 transmitters to serial bus are given in Chapter Connecting the RS

232C serial bus.

Pressing ESC always interrupts any serial command being given. In the commands <cr> means carriage return.

Auto-calibration

NOTE Normally auto-calibration parameters do not have to be changed.

DRYCAL<cr>

>drycal

DCAL ON

Interval min : 60 ?

Max dTdp: 2.00 ?

dTdp time s : 10 ?

Max corr. : 0.040 ?

Settl time s : 50

>

46_____________________________________________________________________M210492 EN A


NOTE

The interval parameter defines the frequency of auto-calibration cycles. When the transmitter is turned on, the first auto-calibration takes place after on hour unless the frequency has been set to less than an hour. After the first auto-calibration, the set frequency is activated and the auto-calibration takes place e.g. every six hours. If the setting is changed, it becomes valid only after the next auto-calibration has been completed. If you wish to activate it immediately reset the transmitter or turn it off.

The

Max dTdp

parameter defines the maximum allowed change of the dewpoint value during the pre-defined dTdp

time. If the change in dewpoint value exceeds the limit, the calibration is not started. The auto-calibration is done only after process is stabilized. The transmitter retries untill the calibration is succesfully complited. Note that normally, this parameter does not have to be changed.

The dTdp time

defines the measuring time of the change in dewpoint prior to the auto-calibration (see the parameter

Max dTdp)

.

The Max corr. parameter defines the maximum correction (%RH) the transmitter does during each auto-calibration cycle.

The

Settl time

defines the time the output values prior to the autocalibration are frozen after the calibration. The time is for sensor temperature stabilization.

Normally, the Max dTdp and the Max corr. parameters need not be changed.

NOTE Auto-calibration takes place only when the security lock jumper is connected. With command <fst on>, the serial line printing indicates the stages of the auto-calibration (n = no auto-calibration, w,h,s = different phases in auto-calibration, S = settling time auto-calibration is on).

DCAL<cr>

>dcal

Calibration...

any key to abort

> (appears when the auto-calibration

is completed in 60 - 70 seconds)

V AISALA _________________________________________________________________________ 47


If you press any key, the calibration is interrupted. If no key is pressed, the calibration takes place immediately. If the process is unstable or relative humidity is over 10%, the prompt (>) appears immediately. In that case the calibration is not performed. The calibration is not performed again even if the maximum correction is exceeded. (see Chapter Display/keypad commands)

Pressure compensation

NOTE

PRES pppp.pp <cr> where pppp.pp = absolute pressure (hPa).

value has to be entered in the transmitter memory in order to ensure the best possible measurement accuracy. The pressure setting is used for pressure compensation of the DMP248 transmitter. The pressure is given in hPa/mbar; for converting pressure units, see Appendix 8.

When the command is given, the transmitter first gives the current pressure; after this the new value can be entered or the current one acknowledged.

>PRES <cr>

Pressure : 1013.25 ? 1000.00 <cr>

When the current pressure is known, a new pressure can also be entered directly:

>PRES 1010 <cr>

Pressure : 1010

If the security lock jumper is not connected, the pressure compensation is made with the value 1013.25 hPa.

NOTE If the pressure setting is frequently adjusted, e.g. by using an external barometer as a pressure input source, the command XPRES is recommended (see Appendix 1).

48_____________________________________________________________________M210492 EN A


Analogue outputs

Setting the analogue outputs


AMODE a bb.bbb cc.ccc d ee.eee ff.fff <cr> a bb.bbb

cc.ccc

d

= channel 1: U

I

= lower limit of channel 1

= upper limit of channel 1

= channel 2: U

I

= voltage output

= current output

= voltage output

= current output ee.eee

ff.fff

= lower limit of channel 2


The bb.bbb, cc.ccc, ee.eee and ff.fff parameters are entered in volts or milliamperes.

Example: lower limit of channel 1 is 0 V and upper limit 1 V (U 0 1) lower limit of channel 2 is 2 V and upper limit 10 V(U 2 10)

>AMODE U 0 1 U 2 10 <cr>

Ch1 : 0.000 ... 1.000 V

Ch2 : 2.000 ... 10.000 V

Selecting and scaling the analogue output quantities


ASEL xxx yyy <cr>

V AISALA _________________________________________________________________________ 49

OPERATING MANUAL _______________________________________________________________ xxx yyy

=

= channel 1's quantity channel 2's quantity (RH, T, Td, ppm)

Example: dewpoint temperature selected on channel 1 and temperature on channel 2

>ASEL Td T <cr>

Ch1 ( Td ) lo -50.00 'C ? -40<cr>

Ch1 ( Td ) hi 10.00 'C ? 0<cr>

Ch2 ( T ) lo 10.00 'C ? 0<cr>

Ch2 ( T ) hi 100.00 'C ? 60<cr>

>

Scaling the analogue outputs


ASCL <cr>

Example: dewpoint is scaled in the range of -40...0 °C and temperature in the range of 0...+60 °C

>ASCL <cr>

Ch1 ( Td ) lo -50.00 'C ? -40<cr>

Ch1 ( Td ) hi 10.00 'C ? 0<cr>

Ch2 ( T ) lo 10.00 'C ? 0<cr>

Ch2 ( T ) hi 100.00 'C ? 60<cr>

>

Output via the serial bus

Starting the measurement output

R <cr>

Starts output of measurements to the peripheral devices (RUN mode); the only command that can be used is S (stop).

The output format can be changed with command FORM (see

Appendix 1).

50_____________________________________________________________________M210492 EN A


Stopping the measurement output

S<cr>

Ends the RUN mode; after this command all other commands can be used.

Outputting the reading once

SEND <cr> in STOP mode or

SEND aa <cr> in POLL state aa = address of the transmitter when more than one transmitter is connected to a serial bus (0...99)

Output:

Td= -9.3 'C PPM= 2733 T= 22.1 'C RH= 10.4 %RH

Td= -9.3 'C PPM= 2730 T= 22.1 'C RH= 10.4 %RH

...

The output format can be changed with command FORM (see

Appendix 1).

Setting the output interval for the RUN mode

INTV xxx yyy <cr> xxx = output interval (0...255)

0: no pause between outputs yyy = unit (s, min or h)

Example: output interval is changed into 10 minutes

>INTV 10 min <cr>

Output intrv. : 10 min

V AISALA _________________________________________________________________________ 51


NOTE


SERI b p d s x <cr> d s b p x

= bauds (300, 600, 1200, 2400, 4800, 9600)

= parity (n = none, e = even, o = odd)

= data bits (7 or 8)

= stop bits (1 or 2)

= duplex (H = half, F = full)

The settings can be changed one parameter at a time or all parameters at once:

>SERI O <cr>

4800 O 7 1 HDX changing parity only

>SERI 600 N 8 1 F <cr>

600 N 8 1 FDX changing all parameters



DMP248 programme will change the number of stop bits to 2



When the half-duplex mode is set, it will automatically turn the echo off. Even then, the ECHO command can indicate that echo is on.


UNIT x <cr> x = m / n m= metric units (

°

C) n= non-metric units) (

°

F)

Setting the transmitter address

ADDR aa <cr> aa = address (0...99)

Example: transmitter is given address 99

>ADDR <cr>

Address : 2 ? 99 <cr>

52_____________________________________________________________________M210492 EN A


Resetting the transmitter

RESET <cr>

Operating the transmitter via the serial bus

Setting the serial interface

SMODE xxxx<cr> xxxx = STOP, RUN or POLL

In STOP mode: measurements output only by command, all commands can be used

In RUN mode: outputting automatically, only command S can be used

In POLL mode: measurements output only with command SEND.

When in POLL state, the output state is changed as follows:

OPEN aa <cr>

SMODE xxxx<cr> aa = xxxx = address of the transmitter

STOP, RUN or POLL

The OPEN command sets the bus temporarily in STOP state so that the

SMODE command can be given.

Example:

>SMODE STOP <cr> setting STOP state

Serial mode : STOP

OPEN & CLOSE

OPEN nn <cr> nn = address of the transmitter (0...99)

CLOSE <cr>

In STOP mode: command OPEN has no effect, CLOSE sets the transmitter in POLL mode temporarily

In POLL mode: command OPEN sets the transmitter temporarily in

STOP mode, command CLOSE returns the instrument to POLL mode

V AISALA _________________________________________________________________________ 53


Example: relative humidity calibration is performed at transmitter

2 which is in POLL state

>OPEN 2 <cr>

>CRH <cr>

...

>CLOSE <cr> opens the line to transmitter 2 calibration started line closed

54_____________________________________________________________________M210492 EN A

C HAPTER 6 ______________________________________________ CALIBRATION AND ADJUSTMENT

CHAPTER 6

CALIBRATION AND

ADJUSTMENT

NOTE

The DMP248 transmitter is fully calibrated and adjusted as shipped from factory. The recommended humidity calibration interval is one year.

A hand-held dewpoint meter DM70 can be used in field-checking of the DMP248.

The adjustments of the temperature measurement channel and the analogue outputs are particularly stable and in normal circumstances, there is no need to recalibrate them.

To achieve the best accuracy in low dewpoints, the DMP248 shall be sent once a year to Vaisala Service Centers for dewpoint calibration and adjustment.

Humidity calibration and adjustment

The DMP248 transmitter is calibrated against two accurate RH references. The calibration can be performed by the end-user, or the instrument can be sent to Vaisala (see page 71) or a Vaisala representative. A two-point calibration and adjustment can be performed with Vaisala’s HMK15 Calibrator.

Calibration can be performed by giving the commands using the press switches inside the housing, through the serial bus (serial commands) or through the menus on the local display (display/keypad commands).

V AISALA _________________________________________________________________________ 55


NOTE

When LED commands are used and when the two analogue channels do not output either relative humidity and/or temperature, relative humidity is calibrated on channel 1 and temperature is calibrated on channel 2. The calibration ranges are 0...100 %RH and -20...+80 °C.

When the transmitter is calibrated at two points, the points must be either 50 %RH or 50 C apart from each other.

As relative humidity is a temperature dependent parameter, the probe and the salt bath calibrator have to stabilize to the same temperature for best accuracy.

Two-point calibration and adjustment adjustment procedure

A two-point humidity calibrationand adjustment should be performed in stable conditions using saturated salt solutions as references.

Using serial commands

•

Leave the calibrator and the transmitter for at least 4 hours in the same space so that their temperatures have time to equalize.

Remove the filter cap on the transmitter.

Disconnect the security lock jumper before turning the transmitter on!

•

Place the sensor head in the calibration hole of the LiCl bottle (dry end reference) in the humidity calibrator.

•

Wait for 30 minutes.

•

Give command CRH <cr>, enter the first point value and press

<cr>.

>CRH <cr>

RH : xx.x Ref1 ? yy.y <cr>

Press any key when ready...

•

If you want to see how the sensor stabilizes to the humidity in the calibrator, enter c <cr> instead of the first reference:

RH : 11.9 Ref1 ? c <cr>

RH : 11.5 Ref1 ? c <cr>

56_____________________________________________________________________M210492 EN A


RH : 11.5 Ref1 ? 11.3 <cr>


•

Place the sensor head in the calibration hole of the NaCl bottle

(wet end reference) in the humidity calibrator.

•


•

Press any key and enter the second point value and press <cr>.

RH : xx.x Ref2 ? yy.y <cr>

•

The stabilization of the sensor can be monitored here as well by entering c <cr> instead of the reference value.

Using display/keypad commands

•




•


•

Select

Cali

in the main menu and then

RH

; select

Not changed and then two-point calibration

RH 2 point cal

. Change the first point reading with the arrow keys to correspond the reference humidity and press ENT; pressing an arrow once changes the reading by 0.05 %RH.

•



•


V AISALA _________________________________________________________________________ 57


•

If necessary, change the second point reading with the arrow keys and press ENT.

Using LED commands

•




•


•

Connect an ammeter/voltmeter to the analogue outputs (connector

X2). Give command

¡¡¡l

. At the first calibration point the

LED on the left flashes; adjust the first point (offset) with the arrow switches to the value given in the calibration table and press

ENT switch.

•



•


•

Check that the reading corresponds within the desired accuracy to that given in the calibration table. If not, adjust the second point with the arrow switches to the correct value and press ENT. At the second calibration point the second LED from the left flashes.

58_____________________________________________________________________M210492 EN A


Humidity calibration table

T ABLE 6-1

Temperature

LiCl

4...20 mA

0...20 mA

0...1 V

0...5 V

0...10 V

Greenspan's calibration table

°C

°F

%RH

15

59

*

20

68

11.3

5.81

2.26

0.113

0.565

1.13

25

77

11.3

5.81

2.26

0.113

0.565

1.13

30

86

11.3

5.81

2.26

0.113

0.565

1.13

35

95

11.3

5.81

2.26

0.113

0.565

1.13

NaCl

4...20 mA

0...20 mA

0...1 V

0...5 V

0...10 V

%RH 75.6

16.10

15.12

0.756

3.780

7.56

75.5

16.08

15.10

0.755

3.775

7.55

75.3

16.05

15.06

0.753

3.765

7.53

75.1

16.02

15.02

0.751

3.755

7.51

74.9

15.98

14.98

0.749

3.745

7.49

*) If the LiCl solution is used or stored in temperature below +18 °C (+64 °F), the equilibrium humidity of the salt solution changes permanently.

Temperature calibration

The temperature channel has been calibrated at the factory and since it is very stable, adjustment should be made only when there is strong reason to believe that the adjustments have changed.

Temperature calibration should be performed against some accurate temperature reference. It can be done either using the press switches inside the housing, through the serial bus or the menus on the local display. Either a one point offset correction or a two point calibration is possible.

One point offset correction


•

Leave the reference instrument and the transmitter for at least 4 hours in the same space so that their temperatures have time to equalize. Remove the filter cap prior to calibration.


V AISALA _________________________________________________________________________ 59


•

Check the transmitter against the reference.

•

Give command CT <cr>, enter the first point value and press <cr>:

>CT <cr>

T : xx.x Ref1 ? yy.y <cr>

Press any key when ready

•

If you want to see how the sensor stabilizes to the reference temperature, enter c <cr> instead of the first reference:

T : 0.90 Ref1 ? c <cr>

T : 0.55 Ref1 ? c <cr>

T : 0.55 Ref1 ? 0.0 <cr>


•

After giving the correct temperature value (Ref1) and pressing

<cr> press any key and then <cr>.


•



•


•

Select

Cali


T

; select one-point calibration

T 1 point cal

.

•

Change the reading with the arrow keys to correspond to the reference and press ENT.


•



•


60_____________________________________________________________________M210492 EN A


•


X2). Give command ¡¡l¡ . At the first calibration point the

LED on the left flashes; adjust the first point (offset) with the arrow switches to the same reading with the reference and press

ENT switch.

•

After adjusting the offset point and pressing ENT the second LED from left flashes. Press ENT without changing the output value.

Two-point temperature calibration and adjustement


•



•


•

Give command CT <cr>, enter the first point value and press <cr>:

>CT <cr>



•

If you want to see how the sensor stabilizes to the reference temperature, enter c <cr> instead of the first reference:

T : 0.90 Ref1 ? c <cr>

T : 0.55 Ref1 ? c <cr>

T : 0.55 Ref1 ? 0.0 <cr>


•

Change the temperature and again check the transmitter against the reference.

•

Check that the reading corresponds with the reading of the reference instrument. If not, adjust the second point.

•

Press any key, enter the second point value and press <cr>.


V AISALA _________________________________________________________________________ 61


•

The stabilization of the sensor can be monitored well by entering c

<cr> instead of the reference value.


•



•


•

Select

Cali


T

; select two-point calibration

T 2 point cal

. Change the first point reading with the arrow keys and press ENT.

•


•


•

If necessary, change the second point reading with the arrow keys and press ENT.


•



•


•


X2). Give command

¡¡l¡

. At the first calibration point the

LED on the left flashes; adjust the first point (offset) with the arrow switches to the same reading with the reference and press

ENT switch.

•


62_____________________________________________________________________M210492 EN A


•


•

If necessary, adjust with the arrow switches to the correct value and press ENT. At the second calibration point the second LED from the left flashes.

Calibration of the analogue outputs

The analogue outputs have been calibrated at the factory and since they are very stable, calibration of the outputs should be performed only when there is reason to believe that their adjustments have changed.



ACAL <cr>

The outputs on channels 1 and 2 are measured and the measured values (mA or V) entered as calibration coefficients.

Example: both channels have 0...10 V outputs (set with AMODE command); enter the voltages measured at the analogue outputs:

>ACAL <cr>

Ch1 U1 ( V ) ? 0.123 <cr>

Ch1 U2 ( V ) ? 9.98 <cr>

Ch2 U1 ( V ) ? 0.120 <cr>

Ch2 U2 ( V ) ? 9.98 <cr>



•

Connect an ammeter/voltmeter to the output of channel 1, select

Cali


Analog outputs

in the Cali menu. The following is displayed (the quantity can be either mA or V):

V AISALA _________________________________________________________________________ 63


•

Enter the measured lower end current/voltage on channel 1.

•

Enter the measured upper end current/voltage on channel 1.

•

Connect the meter to the output of channel 2 and enter the measured lower end current/voltage on channel 2.

•

Enter the measured upper end current/voltage on channel 2.


If both the analogue outputs and humidity/temperature channels are calibrated, the analogue outputs should be calibrated first. This applies only when the calibrations are done using the LED commands!

• connect an ammeter/voltmeter to the analogue outputs (connector

X2)


•

Give command

¡¡ll

.

• the LED on the left flashes; set the low end of channel 1 with the arrow keys and press ENT

• the second LED from the left flashes; set the high end of channel 1 with the arrow keys and press ENT

64_____________________________________________________________________M210492 EN A


• the LED on the left flashes; set the low end of channel 2 with the arrow keys and press ENT

• the second LED from the left flashes; set the high end of channel 2 with the arrow keys and press ENT

The analogue outputs are calibrated to ensure that outputs are correctly scaled: for example, when the output is scaled to 4...20 mA, the low end of the scale is 4 mA and high end 20 mA exactly.

However, when 0... 20 mA output is used, the output can not be adjusted to exactly 0 mA, but to 50 µA. When 0...1 V, 0...5 V or 0...10

V output is in use, the output is adjusted to 50 mV. The following table summarizes the correct output values.

T ABLE 6-2 Summary of the correct output values

Output scale:

0...20 mA 4...20 mA 0...1 V low end: 50 µA high end: 20 mA

4 mA

20 mA

50 mV

1 V

0...5 V

50 mV

5 V

0...10 V

50 mV

10 V

V AISALA _________________________________________________________________________ 65

C HAPTER 7 ____________________________________________________________MAINTENANCE

CHAPTER 7

MAINTENANCE

Reference measurements

Reference measurements are needed to verify whether the transmitter readings are within specifications. This way the user can check if the transmitter needs calibration or service.

The reference measurement should be made as close to the checked sensor as possible and the readings should be read at the same time, when possible. A re-calibrated DMP248 transmitter can be used as a reference.

Self-diagnostics

The DMP248 transmitter goes through a self-diagnostics procedure when the power is switched on. If the procedure does not reveal any errors or faults, the transmitter starts operating normally. If errors or faults are found, check first if the DRYCAP



sensor is damaged. If it is intact, send the transmitter to Vaisala or a Vaisala representative for repairs. The error messages the transmitter outputs are listed in

Appendix 5.

If any errors occur during operation, the error messages are output on the local display if the transmitter displays measurements; if the menus are used, error messages are not output. The LEDs indicate errors at all times. During operation, however, the error messages are not output automatically through the serial interface. If there is any reason to doubt that there is something wrong with the transmitter, use command ERRS:

V AISALA _________________________________________________________________________ 67


ERRS <cr>

If there are no error messages, only a prompt is displayed:

>ERRS <cr>

>

When errors have occurred, the transmitter outputs the error code (see

Appendix 5 for all error messages):

>ERRS <cr>

E40 f ( all ) out of range

>

Temperature channel adjustment with Pt 100 simulators

Switch the power off and disconnect the wires to the Pt 100 sensor from solder lugs TP5, TP6 and TP7.

TP6 TP7

X88

F IGURE 7-1

TP5

Location of solder lugs TP5, TP6 and TP7 and connector X88

Connect a Pt 100 simulator to connector X88 and set it at the lowest temperature to be calibrated.

Pt 100

X88

F IGURE 7-2 Connecting the Pt 100 simulator to connector X88

Switch the power on.

68_____________________________________________________________________M210492 EN A

C HAPTER 7 ____________________________________________________________MAINTENANCE

Adjustment using serial commands

Give command CT and enter the first point value and press <cr>:

>CT <cr>

'C : xx.x Ref1 ? yy.y <cr>


Set the Pt 100 simulator at the highest temperature to be calibrated, and press any key. Enter the second point (gain) reference reading. If second reference is not needed, press <cr> to complete one point offset correction.

Adjustment using display commands

Select Cali in the main menu and then T ; select two-point calibration T

2 point cal

. Change the first point reading with the arrow keys and press ENT.

Set the Pt 100 simulator at the highest temperature to be calibrated, and adjust the second point (gain) to the reference reading.

Adjustment using LED commands


X2). Give command

¡¡l¡

, and adjust the first point (offset) with the arrow switches to the same reading with the reference and press

ENT switch.

Set the Pt 100 simulator at the highest temperature to be calibrated, and adjust the second point (gain) to the reference reading. If there is no second reference, press ENT to complete one point offset correction.

Disconnect the Pt 100 simulator and reconnect the Pt 100 wires to solder lugs TP5, TP6 and TP7.

The correct connections according to the wire colours are:

TP5 blue

TP6 green

TP7 yellow

TP8 black

If there is not a Pt 100 simulator available, the adjustment can be made with two resistors of 84

Ω

and 154

Ω

whose resistance is known precisely. Measure the resistor with a resistance meter. Look up the

V AISALA _________________________________________________________________________ 69

OPERATING MANUAL _______________________________________________________________ corresponding temperature value from a Pt 100 conversion table or calculate it using the following equation:

T

=

D0

+

R x {D1

+

R x [D2

+

R x (D3

+

R x D4)]} (7-1) where

D0

D1

D2

D3

D4

=

=

=

=

=

-243.5673014

2.278542701

0.002050681

-6.15025E-06

1.34949E-08

Measurement of output currents using test points

If a current output has been connected e.g. to a process computer, the output current cannot be measured at the output connector X2 without disconnecting the external load. The output current can, however, be measured at test points CH1+/CH1- and CH2+/CH2- without disconnecting the output wires. These test points can therefore be used in one point offset correction against an accurate reference or in checking the current output without disconnecting the analogue output from the process.

CH1 +

+ CH2

X15

X2


F IGURE 7-3 Location of the CH1 and CH2 test points

70_____________________________________________________________________M210492 EN A

C

HAPTER

7____________________________________________________________ MAINTENANCE mA

CH1+ CH1-

TEST POINTS

X2

CH1+

CH1-

R

L

F

IGURE

7-4 Circuit diagram of the analogue output current test points

Adjusting the contrast of the display

The contrast of the display can be adjusted using the trimmer "LCD display contrast" located next to the press switches.

Vaisala Service Centers

NORTH AMERICAN SERVICE CENTER

Vaisala Inc., 100 Commerce Way, Woburn, MA 01801-1068, USA.

Phone: +1 781 933 4500, Fax +1 781 933 8029

Email: [email protected]

EUROPEAN SERVICE CENTER

Vaisala Instruments Service, Vanha Nurmijärventie 21 FIN-01670 Vantaa,

FINLAND.

Phone: +358 9 8949 2758, Fax +358 9 8949 2295

E-mail: [email protected]

ASIAN SERVICE CENTER

Vaisala KK, 42 Kagurazaka 6-Chome, Shinjuku-Ku, Tokyo 162-0825, JAPAN.

Phone: +81 3 3266 9611, Fax +81 3 3266 9610

E-mail : [email protected]

www

.

vaisala.com

V AISALA _________________________________________________________________________ 71


CHAPTER 8

TECHNICAL DATA

Measured variables

Dewpoint temperature

Measurement range -60...+80 °C

(below 0 °C DMP248 outputs frostpoint)

Dewpoint accuracy

(see figure below)

± 2 °C (-50...+80

°

C)

F IGURE 8-1 Measurement range and accuracy.

Response time (90%) at flow rate 0.08 m/s

(1 bar) at 20 °C:

-40

→

-20 °C dp 35 s

-20

→

-40 °C dp 240 s

72_____________________________________________________________________M210492 EN A

C HAPTER 8 ____________________________________________________________ TECHNICAL DATA

Temperature

Measurement range for specified Td accuracy

Typical accuracy of electronics at +20 °C (+68 °F)

Typical temperature dependence of electronics

Temperature sensor

Relative humidity

Measurement range

Accuracy at 20 °C

RH< 10 %RH

RH> 10 %RH

Ppm volume concentration (dry)

Typical measurement range

Accuracy at 20 °C, 1013.25 mbar

Outputs

Two analogue outputs selectable

-40...+80 °C

0...+80

°

C

±0.1 °C

0.005 °C/°C

Pt 100 IEC 751 1/3 Class B

0...100 %RH

± 0.025 %RH + 8.75% of reading

± 0.7 %RH + 2% of reading

0...5000 ppm v

7.3 ppm v

+ 8.3% of reading

Typical accuracy of an analogue output at +20 °C

Typical temperature dependence of an analogue output

Serial outputs

0...20 mA 4...20 mA

0...1 V

0...10 V

0...5 V

±0.05 % full scale

0.005 %/°C full scale

RS 232C

RS 485 (option) current loop (option)

V AISALA _________________________________________________________________________ 73


General

Sensor

Connections

DRYCAP



S sensor screw terminals, 0.5 mm 2 wires

(AWG 20), stranded wires recommended

Operating voltage 24 VDC/ isolated VAC

(20...28 V)

115 VAC/230 VAC with power supply module

Power consumption 100 mA maximum (24 VDC)

Recommended external load for current outputs <500

Ω

0...1 V voltage output >2 k

Ω

(to ground)

0...5 and

0...10 V voltage outputs >10 k

Ω

(to ground)

Operating temperature range

(electronics) with display cover

-40...+60 °C

0...+50 °C with power supply unit -40...+45 °C

Storage temperature range -40...+70 °C

Pressure range

Housing material

Housing classification

0 ...20 bar absolute pressure

G-AlSi12 (DIN 1725)

IP 65 (NEMA 4)

Bushing for 7...10 mm diameter cable

(8 x 0.5 mm 2 shielded cable)

Sensor protection (

∅

13.5 mm) stainless steel sintered filter

(part no. 16452)

for vacuum applications

Housing dimensions stainless steel filter

(part no. HM46999 )

145 x 120 x 65 mm

74_____________________________________________________________________M210492 EN A

C

HAPTER

8____________________________________________________________

TECHNICAL DATA

Sensor head dimensions:

PROBE

PUSHED

DOWN

ø5.5

P R O B E U P cable length

2, 5 or 10 m adjustment range120 mm

R1/2

ISO 7/1

178

R1/2 ISO 7/1

31

ø13.5

Weight of display cover

29

420 g

Electronics

User interface

Display (option)

Keyboard character height

3 keys and 4 LEDs inside the housing or local display keypad

(option)

2 x 16 character alphanumeric

LCD

3.85 mm (0.15")

1 x 4 keypad

Serial interface modules

Module types

Connections

RS 485/422 digital current loop screw terminals for 0.5 mm 2

Assembly

Number of devices on line

RS 485/422 wires (AWG 20), stranded wires recommended plug-in module

32 digital current loop 6 (single loop), 9 (dual loop)

Network cable type twisted pair

Network line length

Network data speed

1000 m max.

RS 485/422 9600 baud max.

digital current loop 4800 baud max.

V AISALA _________________________________________________________________________ 75


Electromagnetic compatibility

The DMP248 transmitter fulfills the standard EN 61326-1:1997 +Am 1:1998 + Am 2:2001,

Electrical equipment for measurement, control and laboratory use - EMC requirements;

Industrial environment.

Test methods

Emission

Radiated emissions

Immunity

Electrostatic discharge (ESD)

EM field

EFT Burst

Surge

Conducted RF

CISPR16 class B (CISPR22 Class B)

EN/IEC 61000-4-2

EN/IEC 61000-4-3

Industrial environment: 10 V/m

EN/IEC 61000-4-4

EN/IEC 61000-4-5

EN/IEC 61000-4-6

CHAPTER 9

OPTIONS

Power supply

Serial interface

Cable length

Alarm output

Display cover

24 VDC (VAC)(standard),

115/230 VAC

RS 232C (standard), RS 485/422, current loop

0.56, 2, 5 or 10 metres

2 relays 8 A/ 230 V SPCO (Single Pole

Change Over) for adjustable low and high alarm cover with or without local display & keypad

76_____________________________________________________________________M210492 EN A

C HAPTER 10 _______________________________________________ SPARE PARTS AND ACCESSORIES

CHAPTER 10

SPARE PARTS AND

ACCESSORIES

Order code Description

16452SP

DRYCAPS

Sintered filter, stainless steel

DRYCAP ® S dewpoint sensor

Power supply module HMP230PW

5237

HMP230RS

Fuse 160 mA T 5x20 mm for power supply module

RS 485/422 serial module

HMP230CL Current loop module

DMP240ALSP Alarm output unit

17143

DMP248SC

Fuse 8 A for alarm output unit

Sample cell

DMP248BVS Ball valve set

DM70 Hand-held Dewpoint Meter DM70

V AISALA _________________________________________________________________________ 77

A PPENDIX 1 SERIAL COMMANDS __________________________________________________________

APPENDIX 1

SERIAL COMMANDS

APPENDIX 1

A UTO CALIBRATION COMMANDS

DRYCAL Defining the frequency of auto-calibration cycles

DCAL Forced auto-calibration

A NALOGUE OUTPUT COMMANDS

AMODE Setting the analogue outputs

ASEL Selecting the scaling the analogue output quantities

ASCL Scaling the analogue outputs

C ALIBRATION COMMANDS

CRH Relative humidity calibration

CT Temperature calibration

ACAL Calibrating the analogue outputs

L Outputting linear correction coefficients

LI Entering linear correction coefficients

O UTPUT VIA THE SERIAL BUS

R Starting the measurement output

S Stopping the measurement output

SEND Outputting a reading once

DSEND Outputting readings of all connected transmitters once

ERRS Outputting error messages

ECHO Turning the serial interface echo ON/OFF

INTV Setting the output interval for the RUN state

FORM Setting the output format

FTIME Adding time to output

FDATE Adding date to output

SERI Serial bus settings

UNIT Selecting the output units

ADDR Setting the transmitter address

RESET Resetting the transmitter

O PERATION MODES

SMODE Setting the serial interface

OPEN & CLOSE

O THERS

ITEST Testing the analogue outputs

PRES Setting the pressure for pressure compensation and ppm calculations

XPRES Setting the pressure for pressure compensation and for ppm calculations temporarily

CDATE Entering calibration date

DATE Setting the date

TIME Setting the time

VERS Name and version of the programme

? Outputting the transmitter settings

??

Outputting the transmitter settings also in POLL mode

Setting and activating the outputs with menu commands

Setting and activating the outputs using an RS line

The commands function as described when the serial interface is in full-duplex mode and echo is on. All commands except FORM can be given in either capital or small letters.

In the commands <cr> means carriage return, <lf> line feed and <ht> horizontal tabulation.

79

95

95

96

96

97

93

93

94

94

95

89

90

91

92

88

88

89

89

99

99

100

133

134

98

98

98

99

86

87

87

87

88

85

85

85

86

81

81

82

82

82

83

84

V AISALA _________________________________________________________________________ 79


Auto-calibration commands

DRYCAL Defining the frequency of auto-calibration cycles

NOTE

DRYCAL<cr>

>drycal

DCAL ON

Interval min : 60 ?

Max dTdp: 2.00 ?

dTdp time s : 10

Max corr. : 0.040 ?

Settl time s : 50

The interval parameter defines the frequency of auto-calibration cycles. When the transmitter is turned on, the first auto-calibration takes place after on hour unless the frequency has been set to less than an hour. After the first auto-calibration, the set frequency is activated and the auto-calibration takes place e.g. every six hours. If the setting is changed, it becomes valid only after the next auto-calibration has been completed. If you wish to activate it immediately, reset the transmitter or turn it off.

The

Max dTdp

parameter defines the maximum allowed change of the dewpoint value during the pre-defined dTdp

time before autocalibration. If the change in dewpoint value exceeds the limit, the calibration is not started. The auto-calibration is done only after process is stabilized. The dTdp

defines the time for

Max dTdp measurement.

The Max corr. parameter defines the maximum correction (%RH) the transmitter does during each auto-calibration cycle. The Settl time defines the time the output values (measured before auto-calibration) are frozen after the auto-calibration. The time is for sensor temperature stabilization.

Normally, the Max dTdp and the Max corr. parameters need not be changed.

NOTE Auto-calibration takes place only when the security lock jumper is connected.

V AISALA _________________________________________________________________________ 81


DCAL Forced auto-calibration

DCAL<cr>

>dcal

Calibration...

any key to abort

> (appears when the auto-calibration

is completed, max. 60 - 70 seconds)

If you press any key, the calibration is interrupted. If no key is pressed, the calibration takes place immediately. The text above is displayed during the calibration. If the process is unstable (see

Chapter ) or relative humidity is over 10%, the calibration is not performed. The text above is only shortly displayed and the display returns to the measuring mode. The calibration is not performed again even if the maximum correction is exceeded.

Analogue output commands

AMODE Setting the analogue outputs


AMODE a bb.bbb cc.ccc d ee.eee ff.fff <cr> a = channel 1: U = voltage output

I = current output bb.bbb = lower limit of channel 1 cc.ccc

= upper limit of channel 1 d = channel 2: U = voltage output

I = current output ee.eee

= lower limit of channel 2 ff.fff


The bb.bbb, cc.ccc, ee.eee and ff.fff parameters are entered in volts or milliamperes.

Sets the analogue outputs on channels 1 and 2. An example of this is when the voltage output on channel 1 is set to be 0...1 V and channel 2 set to 2...10 V:

82_____________________________________________________________________M210492 EN A


>AMODE U 0 1 U 2 10 <cr>

Ch1 : 0.000 ... 1.000 V

Ch2 : 2.000 ... 10.000 V

The current settings can be checked by giving the command without any parameters:

>AMODE <cr>

Ch1 : 0.000 ... 20.000 mA

Ch2 : 0.000 ... 20.000 mA

ASEL Selecting the scaling the analogue output quantities


ASEL xxx yyy <cr> xxx yyy

= channel 1's quantity (Td, ppm, RH, T)

= channel 2's quantity (Td, ppm, RH, T)

For example, dewpoint temperature is selected to be output on channel 1 and temperature on channel 2; the temperature range is scaled to 0...60

°

C:

>ASEL Td T <cr>

Ch1 ( Td ) lo -50.00 'C ? -40<cr>

Ch1 ( Td ) hi 10.00 'C ? 0<cr>

Ch2 ( T ) lo 10.00 'C ? 0<cr>

Ch2 ( T ) hi 100.00 'C ? 60<cr>

>

When the ASEL command is given on its own, the transmitter outputs its current settings:

>ASEL <cr>

Ch1 ( Td ) lo -50.00 'C ? <cr>

Ch1 ( Td ) hi 10.00 'C ? <cr>

Ch2 ( T ) lo 10.00 'C ? <cr>

Ch2 ( T ) hi 100.00 'C ? <cr>

V AISALA _________________________________________________________________________ 83


The outputs and their scales can also be given directly with the ASEL command.

ASEL xxx yyy aaa.a bbb.b ccc.c ddd.d <cr> xxx yyy

= channel 1's quantity

= channel 2's quantity aaa.a

= lower limit of channel 1 bbb.b

= upper limit of channel 1 ccc.c

= lower limit of channel 2 ddd.d


ASCL Scaling the analogue outputs


ASCL <cr>

Scales the outputs selected on channels 1 and 2.

For example, scaling dewpoint temperature on the range of -40...0 °C and temperature 0...+60 °C:

>ASCL <cr>

Ch1 ( Td ) lo -50.00 'C ? -40<cr>

Ch1 ( Td ) hi 10.00 'C ? 0<cr>

Ch2 ( T ) lo 10.00 'C ? 0<cr>

Ch2 ( T ) hi 100.00 'C ? 60<cr>

>

The output scales can also be given directly with the ASCL command.

ASCL aaa.a bbb.b ccc.c ddd.d <cr> aaa.a

= bbb.b

= ccc.c

= ddd.d

= lower limit of channel 1 upper limit of channel 1 lower limit of channel 2 upper limit of channel 2

For example, when dewpoint temperature is scaled to -40...0

°

C on channel 1 and temperature to 0...+60

°

C on channel 2:

>ASCL -40 0 0 60 <cr>

Ch1 ( Td ) lo -40.00 'C ? <cr>

Ch1 ( Td ) hi 0.00 'C ? <cr>

Ch2 ( T ) lo 0.00 'C ? <cr>

Ch2 ( T ) hi 60.00 'C ? <cr>

>

84_____________________________________________________________________M210492 EN A


Calibration commands

CRH Relative humidity calibration


CT

CRH <cr>

With this command the transmitters can be calibrated against two RH references. Two-point calibration is performed using saturated salt solutions in controlled conditions according to the following instructions:

>CRH <cr>

RH : 12.00 Ref1 ? 11.3 <cr>

Press any key when ready ...

RH : 76.00 Ref2 ? 75.5 <cr>

If the stabilization of the sensor to the humidity in the calibrator needs to be monitored, the measurement output can be repeated by giving command c<cr> at Ref1 and Ref2:

>CRH <cr>

RH : 12.00

Ref1 ? c <cr>

RH : 11.70

Ref1 ? c <cr>

RH : 11.50

Ref1 ? 11.3 <cr>


RH : 76.00

Ref2 ? 75.5 <cr>

Temperature calibration


CT <cr>

Using this command the transmitters can be calibrated against an accurate reference, such as a Pt 100 simulator. A two-point calibration is performed as follows:

>CT <cr>

T : 0.80

Ref1 ?

0.0 <cr>


T : 56.20

Ref2 ?

55.0 <cr>

V AISALA _________________________________________________________________________ 85


In one-point offset correction, the Ref2 prompt is acknowledged with <cr>:

>CT <cr>

T : 0.80

Ref1 ?

0.0 <cr>


T : 75.50

Ref2 ?

<cr>

If the stabilization of the sensor to the temperature of the calibrator or the reference needs to be monitored, the measurement output can be repeated by giving command c<cr> at Ref1 and Ref2:

>CT <cr>

T : 0.80

T : 0.40

Ref1 ?

Ref1 ?

c <cr>

0.00 <cr>


T : 56.20

Ref2 ?

55.0 <cr>

ACAL Calibrating the analogue outputs


L

ACAL <cr>

Calibrates the outputs selected on channels 1 and 2. The output is measured and the measured values (mA or V) entered as calibration coefficients.

For example, calibrating the outputs when 0...10 V signal has been selected on both channels (set with AMODE command)

>ACAL <cr>

Ch1 U1 (V ) ?

0.123 <cr>

Ch1 U2 (V ) ?

9.98 <cr>

Ch2 U1 (V ) ?

0.120 <cr>

Ch2 U2 (V ) ?

9.98 <cr>

Outputting linear correction coefficients

L <cr>

Calibration coefficients can be checked with command L.

>L <cr>

RH offset : 0.000

RH gain : 1.000

Ts offset : 0.000

Ts gain : 1.000

86_____________________________________________________________________M210492 EN A


LI Entering linear correction coefficients


NOTE

LI <cr>

The LI command is one way of calibrating the transmitters.

>LI <cr>

RH offset

RH gain

Ts offset

Ts gain

: 0.000 ? -.6 <cr>

: 1.000 ? <cr>

: 0.000 ? <cr>

: 1.000 ? .4 <cr>

The factory settings are offset 0 and gain 1.

The temperature unit in offset correction is always degrees

Centigrade, even if the transmitter is using non-metric units

(Fahrenheit) in its measurement output.

Output via the serial bus

R Starting the measurement output

R <cr>

Starts output of measurements to the peripheral devices (PC display or printer); output interval is set with command INTV.

Factory setting of the output format:

Td= -9.3 'C PPM= 2733 T= 22.1 'C RH= 10.4 %RH

Td= -9.3 'C PPM= 2730 T= 22.1 'C RH= 10.4 %RH

...

When the transmitter sends out the readings, the serial interface does not echo any commands; the only command that can be used is S (stop).

The output format can be changed with command FORM.

V AISALA _________________________________________________________________________ 87


S Stopping the measurement output

S<cr>

Ends the RUN state; after this command all other commands can be used.

SEND Outputting a reading once

SEND <cr> in STOP state or

SEND aa <cr> in POLL state aa = address of the transmitter when more than one transmitter is connected to a serial bus (0...99; set with command ADDR)

Outputs the current measurement readings via the serial line. The output type is the following:

Td= -9.3 'C PPM= 2733 T= 22.1 'C RH= 10.4 %RH

Td= -9.3 'C PPM= 2730 T= 22.1 'C RH= 10.4 %RH

...

The output format can be changed with command FORM.

DSEND Outputting readings of all connected transmitters once

DSEND <cr>

All transmitters connected to the serial bus send their addresses and current measurement readings in an order defined by their addresses. After receiving

DSEND command a transmitter sets a delay time according to its address value and sends the data after this delay. DSEND works also in POLL mode. With this command, the user can for example easily find out the addresses of the transmitters.

The output when four transmitters with addresses 4, 5, 10, 33 have been connected to the serial bus:

>dsend <cr>

4 14.43 %RH

5 22.7 'C

10 14.99 %RH

33 22.3 'C

>

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ERRS Outputting error messages

ERRS <cr>

During operation error messages are not output automatically through the serial interface. If there is any reason to doubt that there is something wrong with the transmitter, possible error messages can be output with command ERRS.

If there are no error messages, only a prompt is displayed:

>ERRS <cr>

>

If errors have occurred, the transmitter outputs the error code (see Appendix 5 for error messages):

>ERRS <cr>

E40 f ( all ) out of range

>

ECHO Turning the serial interface echo ON/OFF

INTV

ECHO xxx <cr> xxx = ON or OFF

When the echo is off, the commands given through the serial interface or the prompt > cannot be seen on the display.

When the serial interface is in half-duplex mode, the echo is always off. Even then the ECHO command can indicate that echo is on.

Setting the output interval for the RUN state

INTV xxx yyy <cr> xxx = yyy = output interval (0...255)

0: no pause between outputs unit (s, min or h)

Sets the output interval when the transmitter outputs measurement readings to a peripheral device.

For example, the currently valid settings are output with:

>INTV <cr>


V AISALA _________________________________________________________________________ 89


When this is changed into 10 minutes, the command is:

>INTV 10 <cr>


The unit is changed into seconds with:

>INTV S <cr>

Output intrv. : 10 s

The change can also be done with one command:

>INTV 10 S <cr>

Output intrv. : 10 s

FORM Setting the output format

FORM <cr>

"xxx...xxx"

? zzz...zzz <cr> xxx...xxx

= zzz...zzz

= old format new format

The FORM command sets the format of the outputs generated in RUN state and by SEND command.

NOTE Please note that capital and small letters have different meanings.

\r

\t

\\

\DD..DD\ dewpoint temperature

\TT..TT\ temperature

\UU..UU\ relative humidity

\MM..MM\ ppm concentration

\PP..PP\ absolute pressure (hPa) (manually feeded value)

\uu..uu\

\n unit according to the preceding variable line feed <lf>

\ carriage return <cr> horizontal tabulation <ht> or <tab>

For example: format

\UUU.UU\ \+TT.TT\\r

\TTT.T\ \uu\\r\n

\UUU.U\ \uuu\\+DD.D\ \uu\\r output

100.00 +99.99 <cr>

15.2 'C <cr><lf>

46.9 %RH +10.8 'C <cr>

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Any text can be written in the command and it appears in the output. For example:

RH: \UUU.U\ T: \+TT.TT\\r RH: 54.0 T: +25 <cr>

The format can be deleted by giving \ as a parameter:

>FORM \<cr> Note. only one space before \ and none after or

>FORM <cr>

"xxx...xxx"

?\<cr>

An example of a format suitable for use in Microsoft Excel spreadsheets:

>FORM <cr>

"xxx...xxx"

?\UUU.U\\t\TTT.T\\t\DDD.D\\t\\r\n <cr>

The output is then:

47.4<tab> 22.4 <tab> 10.6 <tab> <cr><lf>

FTIME Adding time to output

FTIME xxx <cr> xxx = ON or OFF

When FTIME is activated, the current time is output at the beginning of the output line. The time is set with command TIME. After RESET or power on the current time is 00:00:00.

Activating the time output

>ftime on

Form. time : ON

>intv 5 s

Output intrv. : 5 s

>r

09:31:13 RH= 19.4 %RH T= 26.0 'C

09:31:18 RH= 19.4 %RH T= 26.0 'C

09:31:23 RH= 19.8 %RH T= 26.0 'C

09:31:28 RH= 19.6 %RH T= 26.0 'C

09:31:33 RH= 19.5 %RH T= 26.0 'C

09:31:38 RH= 19.5 %RH T= 26.0 'C

...

setting the output interval

V AISALA _________________________________________________________________________ 91


Inactivating the time output

>ftime off

Form. time : OFF

>r

RH= 19.4 %RH T= 26.1 'C

RH= 19.8 %RH T= 26.1 'C

RH= 20.6 %RH T= 26.1 'C

RH= 20.5 %RH T= 26.1 'C

RH= 19.9 %RH T= 26.1 'C

RH= 19.6 %RH T= 26.1 'C

...

FDATE Adding date to output

FDATE xxx <cr> xxx = ON or OFF

When FDATE is activated, the current date is output at the beginning of the output line. The date is set with command DATE. After RESET or power on the current date is 1991-01-01.

Activating the date output

>fdate on

Form. date : ON

>r

1995-03-10 RH= 21.1 %RH T= 26.0 'C

1995-03-10 RH= 21.3 %RH T= 26.0 'C

1995-03-10 RH= 23.1 %RH T= 26.0 'C

1995-03-10 RH= 22.2 %RH T= 26.0 'C

1995-03-10 RH= 20.6 %RH T= 26.0 'C

...

Inactivating the date output

>fdate off

Form. date : OFF

>r

RH= 20.2 %RH T= 26.0 'C

RH= 19.9 %RH T= 26.0 'C

RH= 19.8 %RH T= 26.0 'C

RH= 19.7 %RH T= 26.0 'C

RH= 19.7 %RH T= 26.0 'C

...

92_____________________________________________________________________M210492 EN A


SERI

NOTE


SERI b p d s x <cr> d s b p x

= bauds (300, 600, 1200, 2400, 4800, 9600)

= parity (n = none, e = even, o = odd)

= data bits (7 or 8)

= stop bits (1 or 2)

= duplex (H = half, F = full)

Giving the command on its own outputs the current settings:

>SERI <cr>

4800 E 7 1 FDX

The settings can be changed one parameter at a time or all parameters at once:

>SERI O H <cr>

4800 O 7 1 HDX changing parity and duplex

>SERI 600 N 8 1 F <cr>

600 N 8 1 FDX changing all parameters


• no parity, 7 data bits, 1 stop bit: if this combination is given the DMP248 programme will change the number of stop bits to 2



UNIT

When the half-duplex mode is set, it will automatically turn the echo off. Even then the ECHO command can indicate that echo is on.


x

UNIT x <cr>

= m(etric units) n(on-metric units)

V AISALA _________________________________________________________________________ 93


Td

T

RH metric units non-metric units

°C

°

C

%RH

°F

°

F

%RH

For example, the command for setting the non-metric units is:

>UNIT N <cr>

Output units : non metric

When the command is given with no parameters, the transmitter outputs the currently valid setting.

ADDR Setting the transmitter address

ADDR aa <cr> aa = address (0...99)

The address is used when more than one transmitter is connected to one serial bus. The ADDR command makes it possible to communicate with one transmitter at a time in POLL state.

For example, transmitter is given address 99

>ADDR <cr>

Address : 2 ? 99 <cr>

When asking the current address, no address number is given:

>ADDR <cr>

Address : 2 ? <cr>

RESET Resetting the transmitter

RESET <cr>

Resets the transmitter. All settings that have been changed stay in the memory even after reset or power failure.

94_____________________________________________________________________M210492 EN A


Operation modes

SMODE Setting the serial interface

SMODE xxxx<cr> xxxx = STOP, RUN or POLL

In STOP mode: measurements output only by command, all commands can be used

In RUN mode: outputting automatically, only command S can be used

In POLL mode: measurements output only with command SEND. When in

POLL mode, the output state is changed as follows:

OPEN aa <cr>

SMODE xxxx<cr> aa = address of the transmitter xxxx = STOP, RUN or POLL

The OPEN command sets the bus temporarily in STOP MODE so that the

SMODE command can be given. For example:

>SMODE <cr> which mode is in use at the moment

Serial mode : STOP

>SMODE STOP <cr>

Serial mode : STOP setting STOP mode

OPEN & CLOSE

nn

OPEN nn <cr>

= address of the transmitter (0...99)

CLOSE <cr>

In STOP mode: command OPEN has no effect, CLOSE sets the transmitter in

POLL mode

In POLL mode: command OPEN sets the transmitter temporarily in STOP mode, command CLOSE returns the instrument to POLL mode

When more than one transmitter is connected to the same serial bus, the POLL mode makes it possible to communicate with the transmitters. For example, a relative humidity calibration is performed at transmitter 2 (<bel> = ASCII 7):

V AISALA _________________________________________________________________________ 95


>OPEN 2 <cr>

<cr><lf> 'DMP nn line opened for operator commands'

<cr><lf><lf><bel>

>CRH <cr>

...

>CLOSE <cr>

<cr><lf> 'line closed' <cr><lf>

Others

ITEST Testing the analogue outputs

ITEST <cr> or

ITEST a b <cr> a b

= current/voltage of channel 1

= current/voltage of channel 2

The operation of the analogue outputs can be tested by forcing the outputs to given values which can then be measured with a current/voltage meter from the analogue outputs. The response to ITEST command gives six outputs/parameters. Only the first two are relevant; they show the channel current or voltage in mA or V. The other four figures contain information for service purposes only.

Examples:

• reading the channel outputs and parameters

>itest <cr>

1.9438 2.3483 1.00694 10.64634 1.97374 2.17665

>

• forcing outputs 0.5 V and 4 V to channels 1 and 2

>itest 0.5 4 <cr>

0.5000 4.0000 1.00694 10.62970 1.23336 3.01722

>

• releasing the forced control and reading the outputs

>itest <cr>

1.9427 2.3392 1.00731 10.62428 1.97157 2.16978

>

96_____________________________________________________________________M210492 EN A


PRES Setting the pressure for pressure compensation and ppm calculations

PRES pppp.pp <cr> pppp.pp = absolute pressure (hPa)

If the process pressure differs from the normal ambient pressure, the value has to be entered in the transmitter memory in order to ensure the best possible accuracy. The pressure setting is used for pressure compensation of the

DMP248 transmitter. The pressure also strongly effects the ppm v

value. The pressure is always given in hPa/mbar; for pressure conversion, see Appendix 8.

When the command is given, the transmitter first gives the currently used pressure; after this a new value can be entered or the old one acknowledged.

>PRES <cr>

Pressure : 1013.25 ? 1000.00 <cr>

When the currently used pressure is known, a new pressure can also be entered directly:

>PRES 1010 <cr>

Pressure : 1010

NOTE If the security lock jumper is not connected, the pressure compensation is made with the value 1013.25 hPa.

NOTE If the pressure setting is frequently adjusted, e.g. by using an external barometer as a pressure input source, the command XPRES is recommended.

V AISALA _________________________________________________________________________ 97


XPRES Setting the pressure for pressure compensation and for ppm calculations temporarily

XPRES pppp.pp <cr> pppp.pp = absolute pressure (hPa)

The function and format of XPRES are the same as those of the PRES command except that by using XPRES, the setting is valid only until a reset is given, or power is turned off or pressure is set to zero using XPRES. After this, the pressure stored using command PRES is valid again.

CDATE Entering calibration date

CDATE xxxxxx <cr> xxxxxx = calibration date (000101...991231)

When the latest calibration date has to be kept in memory, it is entered as follows:

>CDATE 940506 <cr>

If the command is given without the date, the transmitter outputs the latest calibration already in memory.

>CDATE <cr>

940420

The date can be given in any format; however, the maximum number of digits is six.

DATE Setting the date

DATE <cr>

For example, to enter a new date:

>DATE <cr>

Current date is 1993-01-30

Enter new date (yyyy-mm-dd) : 1993-06-12 <cr>

When the current date is asked, the new date is passed with <cr>.

98_____________________________________________________________________M210492 EN A


TIME Setting the time

TIME <cr>

For example, to enter a new time:

>TIME <cr>

Current time is 01:35:54

Enter new time (hh:mm:ss) : 13:25:56 <cr>

When the current time is asked, the new time is passed with <cr>.

VERS Name and version of the programme

VERS <cr>

For example:

>VERS <cr>

DMP248 / x.yy

where x.yy is the programme version.

?

Outputting the transmitter settings

? <cr>

For example:

>? <CR>

DMP248 / 1.01

CPU serial nr : A1234567

Keyboard type : 0

Address : 0

Output units : metric

Baud P D S : 4800 E 7 1 FDX

Serial mode : STOP

Output intrv. : 0 s

Mtim : 32

Pressure (hPa): 1013.25

Analog outputs

Ch1 0.00 ... 20.00 mA

Ch2 0.00 ... 20.00 mA

Ch1 ( Td ) lo -40.00 'C

Ch1 ( Td ) hi 100.00 'C

Ch2 ( T ) lo -40.00 'C

Ch2 ( T ) hi 160.00 'C

PRB serial nr : 9619

PRB cal. date : 960611

>

V AISALA _________________________________________________________________________ 99


??

Outputting the transmitter settings also in POLL mode

?? <cr>

Command ?? outputs the same information as command ? but it works also when the transmitter has been set to POLL mode. However, if there are more than one addressed transmitters connected to the serial bus, they all will respond at the same time and the output on the screen will be chaotic.

100____________________________________________________________________M210492 EN A

A PPENDIX 2 ________________________________________________________________________

APPENDIX 2

POWER SUPPLY MODULE

APPENDIX 2 ..................................................................................................................................................... 101

P OWER SUPPLY MODULE .................................................................................................................................. 102

Installing the power supply module ........................................................................................................... 102

T ECHNICAL SPECIFICATIONS ............................................................................................................................ 103

Setting and activating the outputs using an RS line ................................................................................... 134

V AISALA ________________________________________________________________________ 101

A PPENDIX 2_________________________________________________________________________

Power supply module

Installing the power supply module

The mains power connection may be connected to the power supply module only by an authorized electrician. A readily accessible disconnect device shall be incorporated in the fixed wiring (IEC 950).

Remove the plastic plug in the transmitter housing and replace it with the cable gland. Fasten the power supply module to the bottom of the housing with four screws; select the correct mains voltage with voltage selector switch (230/115).

Attach the grounding wire screw and washer to the grounding terminal on the right-hand side of the module. Attach the wires from the power supply module to the power terminal on the main board of the transmitter.

NOTE The jumper in connector X3 has to be in position ON; otherwise no power is supplied to the transmitter.

When the power supply module is on, the power on LED is lit.

RED

BLK from power supply module update the instrument label with the correct supply voltage label according to the selected operating voltage

4 pcs M3 screws for mounting

(prefix with fibre washers)

+ + -

BLK

X3

RED N

L voltage selector switch

115/230 VAC

M4 screw and washer for protective ground terminal

AC mains terminal replace plastic plug with cable gland for ¢ 7...12 mm cable probe cable gland signal cable gland arrange signal cable wires so that they do not reach bare AC wires when the cover is closed power supply cable: strip wires only 5 mm use crimped terminal for ground wire if stranded wire is used

102____________________________________________________________________M210492 EN A

A PPENDIX 2 ________________________________________________________________________

Peel the correct power supply voltage from the sticker enclosed in the power supply module package and attach it on the instrument label to indicate that the supply voltage has been changed.

WARNING Do not detach the power supply module from the transmitter when the power is on.

WARNING Do not connect the power supply to mains when it is not installed in a

DMP248 transmitter.

Technical specifications

Operating voltage

Connections

Bushing

Indicator

Operating temperature range

Storage temperature range

115 VAC (93...127 V)

230 VAC (187...253 V) screw terminals for 0.5...

2.5 mm 2 wire (AWG 20...14) for 7...12 mm diameter cable

PWR ON LED on power supply module board

-40...+45

°

C

-40...+70

°

C

V AISALA ________________________________________________________________________ 103

A PPENDIX 3 ________________________________________________________________________

APPENDIX 3

INSTALLING AND USING THE RS 485/422 SERIAL PORT MODULE

APPENDIX 3 ..................................................................................................................................................... 105

I NSTALLATION ................................................................................................................................................. 106

O PERATION ...................................................................................................................................................... 106

N ETWORK CONFIGURATION ............................................................................................................................. 108

Single loop operation ................................................................................................................................. 108

Dual loop operation.................................................................................................................................... 110

C HECKING THE SERIAL PORT NETWORK OPERATION ........................................................................................ 112

STOP mode................................................................................................................................................ 112

POLL mode................................................................................................................................................ 113

RS 485 network settings............................................................................................................................. 114

S PECIFICATIONS ............................................................................................................................................... 114

V AISALA ________________________________________________________________________ 105

A PPENDIX 3_________________________________________________________________________

Installation

Switch the transmitter off.

Resistors R2, R3 and R4 between connectors X4 and X5 in the component board in the cover of the transmitter are removed with side-cutting pliers. The module is plugged in connectors X4 and X5 on the main board of the DMP248 transmitter; connector X1 on the module board to connector X4 and connector X2 to connector X5.

RX GND TX

Jumper ( ) selections for the

RS 485/422 serial bus module

Single pair

X1 X2

X2

RS 485/422 serial bus module

X5

TX

X1

R2

R3

RX

R4 X4

+ +

Ch1 Ch2

-

X6

T X HI

TX LO

RX H I

RX LO

24V

+ -

Dual pair

X1 X2

Cut off the resistors R2, R3 and R4 on the main board.

New signal names for X6 screw terminal are on the module.

Follow the instructions on the module:

X1 to X4 and

X2 to X5 on the mother board

NOTE! If the transmitter is NOT at the end of the bus OR the line has a dynamic line termination, the resistors R3 and R6 have to be removed!

R6

R3

Connect the data wires to screw terminal X6 on the main board.


Operation

The DMP248 transmitters can either be given an address or operated without an address. Both single and dual loop wiring with half duplex

106____________________________________________________________________M210492 EN A

A PPENDIX 3 ________________________________________________________________________ connection can be used. No address is needed when only one DMP248 transmitter is used; when several transmitters are connected to the same line, each transmitter must be given an address in the initial configuration.

A single transmitter can get its operating voltage from the master or it can have its own (floating) power supply or it has the power supply module in use.

The serial line structure is a parallel interfaced chain (daisy chain). At the ends of the serial line there must be a DMP248 transmitter, dynamic line adapter (120 ohm resistor in series with a 33 nF capacitor) or line master. If a branch line is made with a junction box, the branch should be shorter than 3 meters.

When connecting the device, follow the instructions given in the figure in Chapter 1.

SINGLE LOOP WIRING

TWISTED PAIR WIRING

HOST COMPUTER

TX HI

TX LO

RX HI

RX LO

RX HI

RX LO

TX HI

TX LO

DMP248 transmitters

1 to n pieces

-

RX HI

RX LO

TX HI

TX LO

NOTE: DYNAMIC LINE TERMINATION

REQUIRED IF NO DEVICE

AT THE END OF THE BUS.

120R

33 nF

DUAL LOOP WIRING

TWISTED PAIR WIRING

HOST COMPUTER

TX HI

TX LO

RX HI

RX LO

RX HI

RX LO

TX HI

TX LO

DMP248 transmitters

1 to n pieces

RX HI

RX LO

TX HI

TX LO




120R

120R

33 nF

33 nF

V AISALA ________________________________________________________________________ 107

A PPENDIX 3_________________________________________________________________________

The RS 485/422 module has separate lines for transmitting and receiving, but they can be connected together with jumpers. Dual loop connection is the factory setting; when a single loop connection is used, the positions of jumpers in connector X4 on the module must be changed.

The HI of the receiving line is approx. 0.6 V and its LO is approx. 0 V in order to reduce noise on the lines when no data is transferred

(idling). Both lines are terminated with a 120 ohm resistor in series with a 33 nF capacitor. When operating the transmitter through a single pair, naturally only one line terminal impedance is in use. The line must not be terminated with a resistor alone, as then the power consumption increases too much.

The data lines can withstand short circuit to ground and to each other.

They do not survive connection of supply voltage to the data lines.

The module must be mounted on the main board in the right direction.

It can be mounted in the wrong direction or to the wrong pins without breaking the module; it simply does not work then.

Network configuration

Single loop operation

Bi-directional data on one pair is one of the great advantages of the

RS 485 line. Set jumpers in connector X4 on the module board as shown in the figure below.

X1 X2

X4

X4

This jumper setting connects RX HI to TX HI and RX LO to TX LO and selects only one common line termination. The HI and LO terminals of the RX pair can now be used for operation.

Supplying power from the same end to the whole network prevents common mode voltages from rising too high (over 7 V).

108____________________________________________________________________M210492 EN A

A PPENDIX 3 ________________________________________________________________________

•

•

Connect wires to the transmitter's serial connector.

Check the wiring.

The following procedure must be repeated with all transmitters.

• Open the transmitter cover.

• mounted.

Pull out the RS 485/422 serial port module, if it is already

• Set the serial port of the terminal to 4800 baud, even parity, seven data bits and one stop bit, full duplex (4800 E 7 1 FDX).

RX GND TX

X17

NOTE

• The serial settings of the transmitter must also be 4800 E 7

1 FDX and the transmitter must be in STOP mode. If these factory settings have been changed, they must be changed back. Connect the

RS 232C port of the terminal to connector X17 on the top of the main board and switch the power on.

• Set the address of the transmitter; it can be any number between 1 and 99. In this example the address is 22:

>addr 22

Address : 22

• Set the serial bus settings according to your network specifications. This setting will become valid after next RESET or power off:

•

>seri 2400 e 7 1 h

2400 E 7 1 HDX

Set the transmitter in POLL mode:

>smode poll

Serial mode : POLL

The SMODE command must be given last.

V AISALA ________________________________________________________________________ 109

A PPENDIX 3_________________________________________________________________________

NOTE The transmitter outputs no prompt (>) after the SMODE POLL command and it only reacts to commands which include its address.

•

•

• places.

Check that the transmitter responds to its address:

>send 22

Td= -47.4 'C T= 29.1 'C

Disconnect the terminal.

Check that the jumpers in connector X4 are in the right

X1 X2

X4

X4

•

•

Remount the RS 485/422 serial module.

Close the cover.

• When all transmitters on the network have been configured, switch them off.

Dual loop operation



• mounted.

Pull out the RS 485/422 serial port module, if it is already




110____________________________________________________________________M210492 EN A

A PPENDIX 3 ________________________________________________________________________


When dual loop is used, the jumpers in connector X4 on the module board must be as shown below.

X1 X2

X4

X4

• Set the address of the transmitter, it can be any number between 1 and 99. In this example the address is 22:

>addr 22

Address : 22

• Set the serial bus settings according to your system. This setting will become valid after next RESET or power off:

>seri 2400 e 7 1 f

2400 E 7 1 FDX

• Switch echo on:

>echo on

ECHO : ON

>

• Change the serial output mode into POLL:

>smode poll

Serial mode : POLL


NOTE


• Check that the transmitter responds to its address:

V AISALA ________________________________________________________________________ 111

A PPENDIX 3_________________________________________________________________________

>send 22

RH= 24.4 %RH T= 29.1 'C

•

•


Check that the jumpers in connector X4 are in the right places.

X1 X2

X4

X4

•

•

•

•

Remount the RS 485/422 serial module.

Close the cover.

Repeat this setting procedure with each transmitter.

When all transmitters on the network have been configured, switch them off.

Checking the serial port network operation

Normally measurement readings are asked when the transmitter is in

POLL mode; then the command must include the address of the transmitter. If the settings of the transmitter need to be changed, the transmitter is switched to STOP mode with command OPEN; commands can then be given without address. When the line to the transmitter is closed, it returns to POLL mode.

STOP mode

Open the line to the transmitter: open 22<cr>

DMP 22 line opened for operator commands

Transmitter no. 22 is now temporarily set to STOP mode; it accepts commands sent without address until CLOSE command is given.

Individual settings can now be easily modified. Do not open more than one line at a time.

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Use command ? to find out the settings of the active transmitter:

? <cr>

DMP248 / 1.01

CPU serial nr : 0

Keyboard type : 0

Address : 7


Baud P D S

Serial mode

: 4800 E 7 1 FDX

: STOP


Mtim : 32

Pressure : 1013.25

Analog outputs

Ch1 0.00 ... 10.00 V

Ch2 0.00 ... 10.00 V

Ch1 ( RH )

Ch1 ( RH ) lo hi

0.000 %RH

100.000 %RH

Ch2 ( T )

Ch2 ( T ) lo -20.000 'C hi 180.000 'C

Transducer :

PRB serial nr : 0

Calibr. date : 0

When the necessary settings have been given, close the line to transmitters (the command closes all open lines):

>close line closed

CLOSE command is always given without address. If no lines are open, there will be no response to the CLOSE command.

POLL mode

If a transmitter has been set to POLL mode, it will respond only to commands which include its address: send 22

Td= -47.4 'C T= 29.1 'C

Addresses from 1 to 99 can be used. According to the RS 485/422 standard a maximum of 32 devices can be connected on same bus, but the number can be increased if the line length and/or baud rate is reduced.

The line terminations must be dynamic; e.g. an RC circuit is used instead of a simple resistor termination. Each RS 485 module has a dynamic line termination so it can be used at the end of a line.

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RS 485 network settings

DMP248 settings

Full duplex/half duplex

Echo on/off

Terminal settings

Line feed after carriage return

HDX/FDX single pair dual pair

HDX

OFF

FDX

ON single pair dual pair yes

FDX no

FDX

When terminal is set to general <lf> (line feed) after <cr> (carriage return), the listings will have two line feeds when also the DMP248 transmitters send line feed.

Specifications

Connections on the main board

Assembly

Board dimensions

Operating mode

Berg sockets screw terminals 0.5 mm² wires, stranded wires recommended plug-in module

40 x 28 mm

(single or dual pair wiring)

Network: network type cable type line length max.

number of devices data speed half duplex daisy chain twisted pair

1000 m (3000 ft)

32 devices on line

9600 baud max. for DMP248 transmitters operating mode polling mode common mode voltage range ±7 V

Operating temperature

Storage temperature

-40...+60 °C

-40...+70 °C

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APPENDIX 4

INSTALLING AND USING THE CURRENT LOOP MODULE

I NSTALLATION .................................................................................................................................... 116

O PERATION ....................................................................................................................................... 116

N ETWORK CONFIGURATION ................................................................................................................ 118

Single loop operation................................................................................................................... 118

Single loop wiring ........................................................................................................................ 119

Dual loop operation ..................................................................................................................... 120

Dual loop wiring........................................................................................................................... 121

C HECKING THE SERIAL PORT NETWORK OPERATION ............................................................................. 122

STOP mode................................................................................................................................. 122

POLL mode ................................................................................................................................. 123

Current loop settings ................................................................................................................... 123

Specifications .............................................................................................................................. 124

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Installation

Switch the transmitter off.

Resistors R2, R3 and R4 between connectors X4 and X5 in the component board in the cover of the transmitter are removed with side-cutting pliers. The module is plugged in connectors X4 and X5 on the main board of the DMP248 transmitter; connector X1 on the module board to connector X4 and connector X2 to connector X5.

RX GND TX

X17

Current loop module

X2

X5

X1

R2

R3

R4

X4

X6

RX +

RX -

TX +

TX -

Connect the data wires to screw terminal X6 on the main board.


Operation

The DMP248 transmitters can either be given an address or operated without an address. Both single and dual loop wiring with half duplex connection can be used. No address is needed when only one DMP248 transmitter is used; when several transmitters are connected to the same line, each transmitter must be given an address in the initial configuration.

A current loop must get its operating voltage from the master or it can have its own (floating) power supply capable of supplying 15...40 V and 20...30 mA. Unregulated AC/DC adapter can be used, if the current is limited to 20 mA at least by a serial resistor.

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NOTE The host computer can restrict the loop supply voltage that can be used; see computer specifications.

The serial line structure is a serial interfaced chain (daisy chain). At one end of the serial line there must be a DMP248 transmitter and at the other end a line master. A branch line can be made with a junction box.

SINGLE LOOP WIRING

TWISTED PAIR WIRING

HOST COMPUTER

TX HI

TX LO

RX HI

RX LO

RX HI

RX LO

TX HI

TX LO

DMP248 transmitters

1 to n pieces

-

RX HI

RX LO

TX HI

TX LO




120R

33 nF

DUAL LOOP WIRING

TWISTED PAIR WIRING

HOST COMPUTER

TX HI

TX LO

RX HI

RX LO

RX HI

RX LO

TX HI

TX LO

DMP248 transmitters

1 to n pieces

RX HI

RX LO

TX HI

TX LO




120R

120R

33 nF

33 nF

The digital current loop module has separate lines for transmitting and receiving. Both single loop wiring and dual loop wiring can be used

(see figure). Dual loop connection makes it possible to have a few more transmitters on the same loop pair. A single loop connection has

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A PPENDIX 4_________________________________________________________________________ simpler wiring. Data transmission is achieved by switching the loop current on and off.

Normally, current flows through the loop(s) even when the DMP248 transmitter is not on, so switching one transmitter off does not affect the other transmitters on the loop.

When the wires have been connected correctly, the voltage drop from

RX+ to RX- is below 2 V. If the wires RX+ and RX- or TX+ and TXare connected incorrectly, the voltage drop from RX+ to RX- or from

TX+ to TX- is below 1 V and the transmitter does not work. Even then the current goes through the loop and the other transmitters can be operated normally.

When the loop supply is current limited, the data lines can withstand short circuit to ground and to each other. They do not survive connection of supply voltage to the data lines.

The module must be mounted on the main board in the right direction.

It can be mounted in the wrong direction or to the wrong pins without breaking the module; it simply does not work then. Reverse wiring of

RX+ and RX- or TX+ and TX- does not affect the module.

Network configuration

Single loop operation

Bi-directional data on one pair and galvanic isolation are the advantages of the current loop. Single pair/dual pair use is configured through wiring (see figure).

Supplying power from the same end to the loops prevents crossover voltages.

• Connect wires to the transmitter's serial connector.

• Check the wiring.



• mounted.

Pull out the digital current loop module, if it is already

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RX GND TX

X17

Single loop wiring

• Set the address of the transmitter; it can be any number between 1 and 99. In this example the address is 22:

>addr 22

Address : 22

NOTE

• Set the serial bus settings according to your network specifications. This setting will become valid after next RESET or power off:

•

>seri 2400 e 7 1 h

2400 E 7 1 HDX

Set the transmitter in POLL mode:

>smode poll

Serial mode : POLL



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• Check that the transmitter responds to its address: send 22

Td= -47.4 'C T= 29.1 'C

•

•

•


Remount the digital current loop module.

Close the cover.

• When all transmitters on the network have been configured, switch them off.

Dual loop operation

Single pair/dual pair use is configured through wiring (see figure on page 2).



• mounted.

Pull out the digital current loop module, if it is already





RX GND TX

X17

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Dual loop wiring

• Set the address of the transmitter, it can be any number between 1 and 99. In this example the address is 22:

>addr 22

Address : 22

NOTE

• Set the serial bus settings according to your system. This setting will become valid after next RESET or power off:

>seri 2400 e 7 1 f

2400 E 7 1 FDX

• Switch echo on:

>echo on

ECHO : ON

>

• Change the serial output mode into POLL:

>smode poll

Serial mode : POLL



• Check that the transmitter responds to its address:

>send 22

Td= -47.4 'C T= 29.1 'C

•

•

•

•

•


Remount the digital current loop module.

Close the cover.

Repeat this setting procedure with each transmitter

When all transmitters on the network have been configured, switch them off.

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Checking the serial port network operation

Normally, measurement readings are asked when the transmitter is in

POLL mode; then the command must include the address of the transmitter. If the settings of the transmitter need to be changed, the transmitter is switched to STOP mode with command OPEN; commands can then be given without address. When the line to the transmitter is closed, it returns to POLL mode.

STOP mode

Open the line to the transmitter: open 22<cr>

DMP 22 line opened for operator commands

Transmitter no. 22 is now temporarily set to STOP mode; it accepts commands without address until CLOSE command is given.

Individual settings can now be easily modified. Do not open more than one line at a time.

Use command ? to find out the settings of the active transmitter:

? <cr>

DMP 248 /1.01

CPU serial nr : 0

Keyboard type : 0

Address : 7


Baud P D S

Serial mode

: 4800 E 7 1 FDX

: STOP


Mtim : 32

Pressure : 1013.25

Analog outputs

Ch1 0.00 ... 10.00 V

Ch2 0.00 ... 10.00 V

Ch1 ( RH ) lo 0.000 %RH

Ch1 ( RH ) hi 100.000 %RH

Ch2 ( T )

Ch2 ( T ) lo -20.000 'C hi 180.000 'C

Transducer :

PRB serial nr : 0

Calibr. date : 0

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When the necessary settings have been given, close the line to transmitters (the command closes all open lines):

>close line closed

CLOSE command is always given without address. If no lines are open, there will be no response to the CLOSE command.

POLL mode

If a transmitter has been set to POLL mode, it will respond only to commands which include its address: send 22

Td= -47.4 'C T= 29.1 'C

Addresses from 1 to 99 can be used. According to the 20 mA current loop standard, current flows with no transmission on line. A maximum of 6 devices can be connected on same single loop line, but the number can be increased to 9 by using dual loop wiring.

Current loop settings

DMP248 settings

Full duplex/half duplex

Echo on/off single pair

HDX

OFF

Terminal settings single pair

Line feed after carriage return yes

HDX/FDX FDX dual pair

FDX

ON dual pair no

FDX

When terminal is set to general <lf> (line feed) after <cr> (carriage return), the listings will have two line feeds when also the DMP248 transmitters send line feed.

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Specifications

Galvanic isolation

Loop supply voltage

Loop supply current

1500 VAC/DC max. (1 min)

40 V max.

20 mA nominal must be current limited

Operating loop voltage requirement 4 V/each transmitter (TX+/TX-) on the loop

2 V/each receiver (RX+/RX-)

Loop current

Connections on the main board

Assembly

Board dimensions

Operating mode

(single or dual pair wiring)

Network: network type cable type line length max.

number of devices data speed operating mode isolation voltage proof

Operating temperature

Storage temperature on the loop

12...30 mA (space)

0...2 mA (mark)

30 mA max.

Berg sockets screw terminals 0.5 mm² wires, stranded wires recommended plug-in module

40 x 28 mm half duplex serial daisy chain twisted pair

1000 m (3000 ft)

6 devices on line (single loop)

9 devices on line (dual loop)

4800 baud max.

polling mode

250 VAC (1 min)

-40...+60 °C

-40...+70 °C

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APPENDIX 5

ERROR MESSAGES

APPENDIX 5 ..................................................................................................................................................... 125

E RROR MESSAGES ............................................................................................................................................ 126

Errors after reset......................................................................................................................................... 126

Errors during operation .............................................................................................................................. 127

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ERROR MESSAGES

The DMP248 transmitters go through a self-diagnostics procedure when the power is switched on. When the procedure does not reveal any errors or faults, the transmitter starts operating normally. If errors or faults are found, the transmitter outputs an error message. The error messages can be divided into two groups: error messages after the reset and error messages during operation.

LED symbols:

¡

¤ l

LED dark

LED blinking

LED lit

Errors after reset

Display Serial bus

E11 CPU EEPROM ackn. error

E12 CPU EEPROM csum error

E21 PRB EEPROM ackn. error

E22 PRB EEPROM csum error ackn. error = EEPROM is faulty csum error = check sum is erroneous

The LEDs display these error types as follows:

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¡l¡¡ l¡¡¡

CPU EEPROM error input hybrid error

Errors during operation

Two types of errors are possible during operation of the transmitters.

The first type indicates that no frequency comes from the converter.

Display: Serial bus:

E40 f (all ) out of range

E41 f (T ) out of range

E43 f (Rk1 ) out of range

E44 f (Rk2 ) out of range

E45 f (Ud1 ) out of range

E47 f (Uk1 ) out of range

E48 f (Uk2 ) out of range

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¡¡¤¤

¡¡¤¡

¡¡¡¤ no frequency at all a frequency missing from the RH channel a frequency missing from the T channel

The second error type indicates erroneous y-values (used in internal calculations):

Display: Serial bus:

E51 T y-value out of range

E53 U1 y-value out of range


¤¡¡¡

¡¤¡¡

RH channel y-value out of range

T channel y-value out of range

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APPENDIX 6

A PPENDIX 7 ________________________________________________________________________

APPENDIX 7

Alarm output unit

The alarm output unit consists of two alarm relays and two optoisolated outputs (see Figure 1). The relay output 1 is available at screw terminal X1 and the relay output 2 at screw terminal X2. The optooutputs are activated simultaneously with the corresponding relays and available at screw terminal X5.

ALARM 1 ALARM 2

X1

C NONC CNONC

X2

OPTIONS:

SPCO relay outputs or

-

+

-

+

X5

Figure 1 Relay and opto-outputs

When the relay is not activated, the C and NC outputs of the screw terminal are closed. When the relay is activated, these outputs are opened and the C and NO outputs are closed. If required, the relays can be activated by inserting a jumper to the test connector X4. By inserting the jumper to two pins on the left, relay 1 is activated and by inserting the jumper to two pins on the right, relay 2 is activated.

The alarm output unit is delivered with the alarm outputs in OFF mode (not in use). Therefore, the customer needs to set and take into use the desired outputs.

If the mains power is in use, only an authorized electrician may connect the alarm unit. A readily accessible disconnect device shall be incorporated in the fixed wiring (IEC 950).

For alarm output cabling, remove the plastic plug in the transmitter housing and replace it with the cable gland. Fasten the alarm unit to the bottom of the housing with four screws. Attach the grounding wire with the screw and washer to the grounding terminal on the right-hand

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NOTE side of the module if the mains power is in use. Attach the ribbon cable from X3 of the alarm unit to the X16 on the main board of the transmitter.

NO jumper in connector X4 during normal operation.

When one alarm unit relay is on, the corresponding LED is lit.

NOTE ribbon cable

M3 screws (4 pcs) for mounting

(prefix with fibre washers)

X16 X3

+ + -

M4 screw and washer for protective ground terminal

+ replace the plastic plug with cable gland for ¢7...12 mm cable probe cable gland signal cable gland arrange signal cable wires so that they do not reach bare AC wires when the cover is closed cable: strip wires only 5 mm; use crimped terminal for ground wire if stranded wire is used

Prefix the fastening screws with fiber washers for mounting the unit to the box.

The alarm unit cannot be used with the power supply unit

HMP230PW.

WARNING Do not detach the alarm unit from the transmitter when the power is on.

WARNING Do not connect the mains power to alarm unit without grounding the transmitter.

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Setting and activating the outputs with menu commands


•

Select MORE in the main menu and then ALARM; the following is displayed:

NOTE

•


- the quantity starts blinking; it can be changed with arrow switches, and acknowledged with ENT.

- the third parameter (in this example HI ON) starts blinking. This parameter determines whether the alarm output is in use or not, and when it is activated. Select the output control state with the arrow keys.

The selection is acknowledged with ENT.

The options are the following:

- HI ON (the alarm is activated by exceeding the setpoint, the output is in use)

- LO ON (the alarm is activated if the value goes below the setpoint, the output is in use)

- HI OFF (the alarm is activated by exceeding the setpoint, the output is not in use)

- LO OFF (the alarm is activated if the value goes below the setpoint, the output is not in use)

- The setpoint starts blinking (in this example, -20.00); if you wish to change it, press CL. Use the arrow keys to select the new setpoint digit by digit and acknowledge each digit using the ENT key. Using the CL key, you can correct the entry by deleting the digits one by one. When you have entered the whole setpoint, press ENT for the second time.

- The hysteresis value starts blinking (in this example, 5.00); if you wish to change it, follow the instructions given in previous paragraph.

The options HI OFF and LO OFF are used to deactivate the relay outputs e.g. for service purposes.

The settings of the channel 2 are changed in the same way.

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Setting and activating the outputs using an RS line


ALARM <cr> or

ALARM n ON <cr> where n = channel number (1 or 2)

The currently valid settings of the alarm output unit can be checked with command ALARM:

>alarm<cr>

Ch1 RH LO OFF 0.00

Ch2 RH HI OFF 100.00

>

0.00 %RH

0.00 %RH

This is an example of the factory setting (both alarm outputs are in

OFF mode, i.e. not in use). The settings can be changed with command ALARM:

>alarm 1 Td HI -20 5

Ch1 Td HI OFF -20.00

5.00 'C

Ch2

>

RH HI OFF 100.00

0.00 %RH

When giving this command, first enter the channel number i.e. the number of the alarm output you wish to use (1 or 2). Then select the quantity you wish to have on that channel (Td, ppm, RH or T). The third parameter (HI/LO) determines, whether the alarm is activated when the setpoint value is exceeded (HI) or not reached (LO). The fourth parameter is the actual setpoint value, which activates the alarm. The last parameter is the hysteresis value; it indicates how much the measured value has to exceed or go below the setpoint before the alarm is deactivated. If the third parameter is HI, the alarm is deactivated when the measured value goes below the setpoint with the chosen hysteresis value. If the parameter is LO, the alarm is deactivated when the measured value exceeds the setpoint with the chosen hysteresis value.

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When the alarm outputs have been set, you can activate the outputs with commands ALARM 1 ON (channel 1) or ALARM 2 ON

(channel 2). Note that you can also activate the outputs when giving other parameters with command ALARM.

Examples of activating the outputs: with command ALARM:

>alarm 1 Td HI -20 5

Ch1 Td HI ON -20.00

5.00 'C

Ch2

>

RH HI ON 100.00

0.00 %RH with commands ALARM 1 ON and ALARM 2 ON:

>alarm 1 ON

Ch1 Td HI ON -20.00

Ch2 T

>alarm

HI

2

OFF

ON

30.00

Ch1 Td HI ON -20.00

Ch2 T HI ON 30.00

>

5.00 'C

5.00 'C

5.00 'C

5.00 'C

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APPENDIX 8

Pressure conversion chart

Multiplication factors

NOTE: conversions from mmHg and inHg are defined at 0°C and for mmH

2

O and inH

2

O at 4°C.

FROM: TO: hPa/mbar

PaN/m

2 0.01

mmHg torr 1.333224

33.86388

inHg mmH

2

O inH

2

O atm at

0.09806650

2.490889

1013.25

980.665

bar psi

1000

68.94757

psia = psi absolute

Example: 29.9213 inHg = 29.9213 x 33.86388 = 1013.25 hPa/mbar

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