Vaisala GMP252 User Manual

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M211897EN-B

User Guide

Vaisala CARBOCAP

(R)

Carbon Dioxide Probe

GMP252

PUBLISHED BY

Vaisala Oyj Street address: Vanha Nurmijärventie 21, FI-01670 Vantaa, Finland Mailing address: P.O. Box 26, FI-00421 Helsinki, Finland Phone: +358 9 8949 1 Fax: +358 9 8949 2227

Visit our Internet pages at www.vaisala.com.

No part of this manual may be reproduced, published or publicly displayed in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be modiﬁed, translated, adapted, sold or disclosed to a third party without prior written permission of the copyright holder. Translated manuals and translated portions of multilingual documents are based on the original English versions. In ambiguous cases, the English versions are applicable, not the translations.

The contents of this manual are subject to change without prior notice.

Local rules and regulations may vary and they shall take precedence over the information contained in this manual. Vaisala makes no representations on this manual’s compliance with the local rules

and regulations applicable at any given time, and hereby disclaims any and all responsibilities related thereto.

This manual does not create any legally binding obligations for Vaisala towards customers or end users. All legally binding obligations and agreements are included exclusively in the applicable supply contract or the General Conditions of Sale and General Conditions of Service of Vaisala.

This product contains software developed by Vaisala or third parties. Use of the software is governed by license terms and conditions included in the applicable supply contract or, in the absence of separate license terms and conditions, by the General License Conditions of Vaisala Group.

1. About This Document........................................................................................ 7

1.1. Documentation Conventions................................................................................ 7

1.2. Version Information............................................................................................... 7

1.3. Related Manuals..................................................................................................... 8

1.4. Trademarks............................................................................................................. 8

1.5. Patent Notice..........................................................................................................8

2. Product Overview................................................................................................9

2.1. Introduction to GMP252 .......................................................................................9

2.2. Basic Features and Options................................................................................10

2.3. Operating Principle of CO2 Measurement.......................................................... 11

2.4. Environmental Compensation.............................................................................12

2.4.1. Temperature Compensation......................................................................... 13

2.4.2. Pressure Compensation.................................................................................13

2.4.3. Background Gas Compensation...................................................................13

2.5. Probe Startup........................................................................................................14

2.6. Analog Output Overrange Behavior..................................................................14

2.6.1. Analog Output Overrange Example............................................................ 15

2.7. Safety.....................................................................................................................16

2.7.1. ESD Protection............................................................................................... 16

2.8. Regulatory Compliances......................................................................................16

3. Installation.............................................................................................................17

3.1. GMP252 Probe Dimensions................................................................................. 17

3.2. Recommended Installation..................................................................................17

3.3. Installation Accessories........................................................................................17

3.3.1. 243261SP Installation Flange........................................................................ 18

3.3.2. 243257SP Mounting Clips............................................................................. 19

3.4. Power Supply........................................................................................................19

3.5. Wiring................................................................................................................... 20

4. Vaisala Industrial Protocol..............................................................................21

4.1. Overview................................................................................................................ 21

4.2. Serial Interface Settings.......................................................................................21

4.3. Physical Interface..................................................................................................21

4.4. Connecting with a Computer............................................................................. 22

4.4.1. Installing the Driver for the USB Service Cable......................................... 23

4.5. Accessing Serial Commands from Modbus or Analog Mode......................... 23

4.6. Enabling Modbus Mode from Vaisala Industrial Protocol...............................24

4.7. Changing From Digital Output to Analog Output........................................... 25

4.8. Serial Commands.................................................................................................25

4.9. Device Information and Status...........................................................................28

4.10. Serial Line Output and Communication.............................................................31

4.11. Analog Output..................................................................................................... 39

4.12. Calibration and Adjustment...............................................................................44

4.13. Environmental Compensation Commands...................................................... 48

4.14. Other Commands................................................................................................ 55

5. Modbus...................................................................................................................57

GMP252 User Guide M211897EN-B

6. Operating with MI70 Indicator.................................................................... 58

6.1. Overview of MI70 Support................................................................................. 58

6.2. Basic Display........................................................................................................ 58

6.3. Graphical Display.................................................................................................59

6.4. Main Menu............................................................................................................ 59

6.5. Connecting Probe to MI70 Indicator................................................................. 59

6.6. MI70 Indicator Parts............................................................................................60

6.7. Holding and Saving the Display........................................................................ 60

6.8. Recording Data.....................................................................................................61

6.9. Changing Environmental Compensation Settings with MI70 Indicator........62

6.10. Calibration and Adjustment with MI70 Indicator............................................ 63

6.10.1. 1-Point Adjustment with an MI70-Compatible Reference Probe............ 63

6.10.2. 1-Point Adjustment with a Reference Gas................................................. 64

7. Maintenance.........................................................................................................67

7.1. Cleaning................................................................................................................ 67

7.1.1. Chemical Tolerance....................................................................................... 67

7.2. Changing the Filter..............................................................................................68

7.3. Calibration and Adjustment............................................................................... 68

7.3.1. Calibration Setup.......................................................................................... 69

7.3.2.

Eect of Environmental Compensations...................................................69

7.3.3. Limits of Adjustment....................................................................................70

7.3.4. Adjustment Types.........................................................................................70

7.3.5. DRW244827SP Calibration Adapter............................................................71

8. Troubleshooting................................................................................................. 72

8.1. Problem Situations.............................................................................................. 72

8.2. Error Messages.....................................................................................................72

8.3. Analog Output Error State..................................................................................74

9. Technical Data.....................................................................................................75

9.1. GMP252

Speciﬁcations........................................................................................75

9.2. Spare Parts and Accessories.............................................................................. 78

9.3. GMP252 Probe Dimensions................................................................................ 78

9.4. 243261SP Mounting Flange Dimensions........................................................... 79

9.5. 243261SP Calibration Adapter Dimensions......................................................80

Appendix A:

Modbus Reference..........................................................................81

A.1. Function Codes..................................................................................................... 81

A.2. Modbus Registers................................................................................................. 81

A.2.1. Measurement Data......................................................................................... 81

A.2.2. Conﬁguration Registers................................................................................82

A.2.3. Status Registers............................................................................................ 84

A.2.4. Device Identiﬁcation Objects...................................................................... 84

A.3. Modbus Communication Examples...................................................................86

A.4. Filtering Factor.....................................................................................................88

Technical Support

........................................................................................................... 89

Warranty...........................................................................................................................89

Recycling..........................................................................................................................89

List of Figures

Figure 1 GMP252 Probe Parts........................................................................................... 9

Figure 2 Probe Cuvette with Mirror and Sensor Chips...............................................11

Figure 3 CO2 Measurement in the Measurement Cuvette....................................... 12

Figure 4 Example of Analog Output Overrange Behavior ......................................15

Figure 5 GMP252 Dimensions.......................................................................................... 17

Figure 6 Probe with 243261SP Installation Flange..................................................... 18

Figure 7 Probe in 243257SP Mounting Clips................................................................19

Figure 8 Example of analog output overrange behavior........................................ 43

Figure 9 MI70 Basic Display.............................................................................................58

Figure 10 MI70 Indicator Parts......................................................................................... 60

Figure 11 CO2 Reading with Tcomp and Pcomp on MI70 Screen.......................... 62

Figure 12 Probe Compensation Settings on MI70 Screen.........................................62

Figure 13 Opening the Filter............................................................................................. 68

Figure 14 DRW244827SP Calibration Adapter with Probe Inserted.......................71

Figure 15 GMP252 Dimensions......................................................................................... 78

Figure 16 243261SP Mounting Flange Dimensions..................................................... 79

Figure 17 243261SP Mounting Flange Dimensions, Cross Section......................... 79

Figure 18 243261SP Calibration Adapter Dimensions................................................80

GMP252 User Guide M211897EN-B

List of Tables

Table 1 Document Versions.............................................................................................. 7

Table 2 Related Documents.............................................................................................. 8

Table 3 Applicable Patents................................................................................................8

Table 4 Analog Output Overrange Clipping and Error Limits................................14

Table 5 M12 Male Connector...........................................................................................20

Table 6 Default Serial Interface Settings......................................................................21

Table 7 Basic Serial Commands.....................................................................................26

Table 8 Advanced Serial Commands............................................................................27

Table 9 ? Command.......................................................................................................... 28

Table 10 Errs Command.....................................................................................................28

Table 11 Help Command................................................................................................... 29

Table 12 Snum command.................................................................................................. 29

Table 13 System Command.............................................................................................. 30

Table 14 Time Command...................................................................................................30

Table 15 Vers Command....................................................................................................30

Table 16 Addr Command....................................................................................................31

Table 17 Close Command................................................................................................... 31

Table 18 Form Command................................................................................................... 31

Table 19 Output Parameters for Form Command...................................................... 33

Table 20 Modiﬁers for Form Command.........................................................................34

Table 21 Intv Command..................................................................................................... 35

Table 22 Open Command.................................................................................................. 35

Table 23 R Command..........................................................................................................36

Table 24 S Command..........................................................................................................36

Table 25 Sdelay Command............................................................................................... 36

Table 26 Send Command................................................................................................... 37

Table 27 Seri Command..................................................................................................... 37

Table 28 Smode Command............................................................................................... 38

Table 29 Amode Command.............................................................................................. 39

Table 30 Aover Command................................................................................................ 40

Table 31 Asel Command.................................................................................................... 43

Table 32 Adate Command................................................................................................ 44

Table 33 Atext Command..................................................................................................45

Table 34 Cdate Command.................................................................................................45

Table 35 Ctext Command..................................................................................................45

Table 36 CCO2 Command................................................................................................. 46

Table 37 Env Command.....................................................................................................49

Table 38 O2cmode Command...........................................................................................51

Table 39 Pcmode Command.............................................................................................52

Table 40 Rhcmode Command.......................................................................................... 53

Table 41 Tcmode Command.............................................................................................54

Table 42 Frestore Command.............................................................................................55

Table 43 Pass Command....................................................................................................55

Table 44 Reset Command................................................................................................. 56

Table 45 Default Modbus Serial Communication Settings....................................... 57

Table 46 Performance.........................................................................................................75

Table 47 Operating Environment.................................................................................... 76

Table 48 Inputs and Outputs.............................................................................................77

Table 49 Mechanics............................................................................................................. 77

Table 50 Supported Function Codes...............................................................................81

Table 51 Modbus Measurement Data Registers (Read-Only)..................................81

Table 52 Modbus Conﬁguration Data Registers (Writable).....................................82

Table 53 Modbus Status Registers (Read-Only).........................................................84

Table 54 Device Identiﬁcation Objects.......................................................................... 84

GMP252 User Guide M211897EN-B

1. About This Document

1.1. Documentation Conventions

Chapter 1 – About This Document

DANGER!

carefully at this point, death will follow.

WARNING!

carefully at this point, there is a risk of injury or even death.

CAUTION!

carefully at this point, the product could be damaged or important data could be lost.

Note highlights important information on using the product.

Tip gives information for using the product more eciently.

alerts you to a fatal hazard. If you do not read and follow instructions

alerts you to a serious hazard. If you do not read and follow instructions

warns you of a potential hazard. If you do not read and follow instructions

1.2. Version Information

Table 1 Document Versions

Document Code Date Description

M211897EN-B August 2016 Modbus status register values and

descriptions updated.

M211897EN-A May 2016 First version.

GMP252 User Guide M211897EN-B

1.3. Related Manuals

Table 2 Related Documents

Document Code Description

M211893EN

M211799EN

M211798EN

Vaisala CARBOCAP GMP252 Quick Guide

Vaisala CARBOCAP User Guide

Vaisala CARBOCAP Quick Guide

(R)

Carbon Dioxide Probe

(R)

Carbon Dioxide Probe GMP251

(R)

Carbon Dioxide Probe GMP251

1.4. Trademarks

Vaisala

Windows

(R)

and CARBOCAP

(R)

is either a registered trademark or trademark of Microsoft Corporation in the

United States and other countries.

All other product or company names that may be mentioned in this publication are trade names, trademarks, or registered trademarks of their respective owners.

(R)

are registered trademarks of Vaisala Oyj.

1.5. Patent Notice

This product is protected by the following patents and their corresponding national rights:

Table 3 Applicable Patents

Patent Issued By Patent Number

United States Patent and Trademark Oce US 5,827,438

US 6,177,673

European Patent Oce EP0776023

EP0922972

German Patent and Trade Mark Oce 69615635

Japan Patent Oce 4263285

Finnish Patent Oce 112005

105598

2 3 4 5

Chapter 2 – Product Overview

2. Product Overview

2.1. Introduction to GMP252

GMP252 is designed for CO2 measurement in demanding applications that require reliable and accurate performance. The measurement range is 0 ... 10 000 ppmCO2 (measurements can be carried out in the 10 000 ... 30 000 ppmCO2 range with reduced accuracy).

The probe is based on Vaisala’s patented 2nd generation CARBOCAP equipped with Vaisala's Microglow infrared light source. The probe is easy to install with a plug-in/plug-out M12 connection.

GMP252 is able to compensate for temperature, pressure and background gas. For temperature compensation purposes, the probe includes an internal temperature sensor that allows measurement compensation according to ambient temperature. As dust and most chemicals do not background gas can be compensated for, GMP252 can provide accurate and stable measurements in a wide range of applications.

aect the measurement, and the eect of temperature, pressure and

(R)

technology and

Figure 1 GMP252 Probe Parts

1 5-pin M12 connector. For pinout, see 3.5. Wiring (page 20). 2 Probe name and orientation mark for Vaisala transmitter installations (front) and laser-

printed type label (back).

3 Probe body. Contains the main component board. 4

Measurement cuvette with optics and CARBOCAP

5 Filter (sintered, PTFE)

CAUTION!

inside the probe body.

Do not attempt to open the probe body. There are no user serviceable parts

(R)

CO2 sensor.

GMP252 User Guide M211897EN-B

2.2. Basic Features and Options

• CO2 measurement range 0 ... 10 000 ppmCO2.

• Measurement up to 30 000 ppmCO2 with reduced accuracy.

• Operating temperature range -40…+60 °C (-40...140 ºF).

(R)

• Vaisala CARBOCAP

• Measurement compensated for The temperature compensation can be based on an integrated temperature sensor or use a set temperature. Pressure and background gas parameters can be set to the probe.

• Heating to avoid condensation on optical elements.

• Digital output with RS-485:

• Modbus RTU

• Vaisala Industrial Protocol

• Analog output:

• Current output (0 ... 20 mA or 4 ... 20 mA)

• Voltage output (0 ... 5 V or 0...10 V)

• Compatible with MI70 hand-held meter.

• Easy plug-in, plug-out.

CO2 sensor with excellent long-term stability.

eects of temperature, pressure, and background gas.

More Information

‣

GMP252

‣

Operating Principle of CO2 Measurement (page 11)

‣

Environmental Compensation (page 12)

‣

Modbus (page 57)

‣

Overview of MI70 Support (page 58)

Speciﬁcations (page 75)

Chapter 2 – Product Overview

2.3. Operating Principle of CO Measurement

The Vaisala CARBOCAP probe is a silicon-based, nondispersive infrared (NDIR) sensor for the measurement of gaseous carbon dioxide in air-like gases.

Figure 2 Probe Cuvette with Mirror and Sensor Chips

1 Mirror 2 Cuvette 3 Sensor chips under TO5 package

(R)

sensor used in the

The sensitivity to carbon dioxide is based on absorption of infrared light at a characteristic wavelength. During measurement, infrared light is routed through the cuvette that contains the gas to be measured. A mirror that measures the light intensity at a wavelength determined by a Fabry–Pérot interferometer (FPI) and a band pass

The carbon dioxide measurement consists of two steps: ﬁrst, the FPI is electrically tuned so that its pass band coincides with the characteristic absorption wavelength of carbon dioxide and the signal is recorded. Second, the pass band is shifted to a wavelength where no absorption occurs in order to get a reference signal. The ratio of these two signals, one at the absorption wavelength and the other at the reference wavelength, gives the fraction of light absorption from which the carbon dioxide concentration is calculated. Measuring the reference signal compensates the possible due to dirt on optical surfaces, making the sensor very stable over time.

TO5 packages with hermetic windows are used to protect the sensor chips from moisture and contamination. A heater chip is utilized to prevent condensation in normal operation.

reﬂects the light from the cuvette to a thermopile detector

ﬁlter.

eects of sensor aging and signal attenuation

GMP252 User Guide M211897EN-B

Figure 3 CO Measurement Cuvette

1 Gold-plated mirror 2 Light absorbed by CO2 in the measured

gas

3 Hermetic window 4 Fabry-Perot interferometer 5 Light source (Microglow) 6 Hermetic window 7 Thermopile detector

Measurement in the

2.4. Environmental Compensation

When necessary, various environmental compensations can be applied to improve the CO measurement accuracy of the probe.

The probe can compensate for the eects of the following parameters:

• Temperature

• Pressure

• Background gas oxygen (O2) content

• Background gas relative humidity (%RH)

The probe has an on-board temperature sensor that can be used to compensate for temperature. Additionally, if the probe is integrated in a system that measures one or more of the compensation parameters (T, P, RH, O2), they can be updated to the probe

continuously.

To apply an accurate relative humidity compensation, make sure that also the temperature compensation and pressure compensation environment.

conﬁgurations match the measurement

Chapter 2 – Product Overview

Compensation parameters are conﬁgured on the order form when ordering the probe, and can later be updated using Vaisala Industrial Protocol or Modbus protocol.

You can also turn o any of the compensations. In that case, the probe uses the default compensation value that is mathematically neutral for the probe’s internal compensation model.

2.4.1. Temperature Compensation

The probe can measure the approximate temperature of the CARBOCAP compensation, or use a

ﬁxed setpoint. The temperature measurement is accurate enough to

(R)

sensor for

be useful for compensation, and is recommended for use unless a dedicated temperature measurement is available and can be regularly updated to the probe. If the measurement is made in a constant temperature, this

ﬁxed temperature setpoint can be set as the

compensation value.

If temperature compensation is turned o, the probe uses the default value of +25 °C (+77 °F).

When the probe is installed through a outside the measuring environment, it is possible that temperature conduction from the probe body and cable outside the measurement environment aects the temperature compensation and decreases measurement accuracy.

ﬂange and part of the probe and the cable is left

2.4.2. Pressure Compensation

The probe does not have on-board pressure measurement. However, a pressure reading from an external source can be used as a setpoint value for compensation using Vaisala Industrial Protocol or Modbus.

If pressure compensation is turned o, the probe uses the default compensation value of 1013 hPa.

2.4.3. Background Gas Compensation

The probe does not have on-board oxygen or relative humidity measurement. However, oxygen and relative humidity readings from an external source can be used as setpoint values for compensation using Vaisala Industrial Protocol or Modbus. The default setpoint values are as follows:

• Oxygen concentration: 0 %O2 or 21 %O

• Relative humidity: 0 %RH or 50 %RH

If background gas compensations are turned

In practice, when CO2 is measured at a ppm level, O2 and RH compensations have a very

eect on the accuracy of the measurement.

small

o, the probe uses the value 0 % for both.

GMP252 User Guide M211897EN-B

2.5. Probe Startup

When powered on, the probe starts up within 12 seconds. Measurements from the outputs (digital and analog) become available during this time but note that they will only reach speciﬁed accuracy after a 2-minute warm-up period. For this reason, you should design your system so that it does not rely on measurements from the probe during this time. When the probe is in analog output mode, the probe remains in an error state during the start-up phase until measurement output becomes available.

Speciﬁcally note that the CO2 reading will rise to the correct reading as the sensor’s infrared emitter achieves operation temperature.

2.6. Analog Output Overrange Behavior

Analog output of the probe has a deﬁned behavior when the values measured by the probe are outside the scaled analog output range. At ﬁrst, the output is clipped when the measurement exceeds a set limit (the measurement continues, but the output does not change from the clipped value).

When the measurement exceeds the second limit (error limit), the analog output switches to the error state

deﬁned for the output. The table below lists the clipping and error limits and

default error state outputs for the analog voltage and current outputs.

Table 4 Analog Output Overrange Clipping and Error Limits

Output voltage / current Clipping Limit Error Limit Default Error State Output

0 ... 5 V >5 % >10 % 0 V

0 ... 10 V >1 % >10 % 0 V

0 ... 20 mA >5 % >10 % 23 mA

4 ... 20 mA >5 % >10 % 2 mA

The same clipping and error limits are applied when the measured value drops back to the scaled range: at

ﬁrst the output returns to the clipped value from the error state, and then to

normal output.

Clipping and error state limits the limits are 1 % and 10 %, and for 0 ... 5 V output the limits are 5 % and 10 %.

dier for 0 ... 10 V and 0 ... 5 V outputs. For 0 ... 10 V output

More Information

Output voltage (V)

Time

0.00

In error state at >2200 ppm (2000 ppm + 10%)

5.00

5.25

Clipped at 2100 ppm (2000 ppm + 5%)

Regular measurement

Output clipping limit

Error level

‣

Analog Output Error State (page 74)

2.6.1. Analog Output Overrange Example

Consider a probe with 0 ... 5 V output, scaled to 0 ... 2000 ppmCO2.

Chapter 2 – Product Overview

• When the measured CO

rises above 2000 ppmCO2, the output rises above 5 V.

• The output keeps rising until the measurement is 2100 ppmCO2, at which point the probe outputs 5.25 V.

• If the CO2 level rises above 2100 ppmCO2, the output still remains at 5.25 V.

• If the CO2 level rises above 2200 ppmCO2, the output enters the error state, which is 0 V for the 0 ... 5 V output.

Figure 4 Example of Analog Output Overrange Behavior

This example uses output scaled to 0 ... 5 V and 0 ...2000 ppmCO2, error level set to 0 V, clipping set to 5 % overrange, and error limit set to 10 % overrange. CO2 concentrations (ppm) are indicated for the clipping point and error limit point.

This overrange and error behavior is readings of the digital outputs.

You can change the analog output overrange behavior using the aover command.

speciﬁc to the analog output, and does not aect the

GMP252 User Guide M211897EN-B

2.7. Safety

The probe delivered to you has been tested for safety and approved as shipped from the factory. Note the following precautions:

WARNING!

been exposed to dangerous contamination, and is safe to handle without special precautions.

CAUTION!

lead to malfunction.

CAUTION!

inside the probe body.

When returning a product for calibration or repair, make sure it has not

Do not modify the unit. Improper modiﬁcation can damage the product or

Do not attempt to open the probe body. There are no user serviceable parts

2.7.1. ESD Protection

Electrostatic Discharge (ESD) can cause immediate or latent damage to electronic circuits. Vaisala products are adequately protected against ESD for their intended use. However, it is possible to damage the product by delivering electrostatic discharges when touching an exposed contact on the product.

To make sure you are not delivering high static voltages yourself, avoid touching the pins on the M12 connector.

2.8. Regulatory Compliances

The probe is in conformity with the provisions of the following EU directives:

• RoHS Directive

• EMC Directive

Conformity is shown by compliance with the following standards:

• EN 50581: Technical documentation for the assessment of electrical and electronic products with respect to the restriction of hazardous substances.

• EN 61326-1: Electrical equipment for measurement, control, and laboratory use – EMC requirements – Generic environment.

• EN 55022: Information technology equipment – Radio disturbance characteristics – Limits and methods of measurement.

3. Installation

12 mm 76 mm 42 mm

130 mm, Ø 25 mm

3.1. GMP252 Probe Dimensions

The dimensions are given in millimeters (mm).

Chapter 3 – Installation

Figure 5 GMP252 Dimensions

3.2. Recommended Installation

The probe can be installed in an environment with an operating temperature range -40 ... +60 °C (-40 ... +140 °F). Make sure the probe is in a location that represents the measurement environment properly.

The 5-pin male M12 connector on the probe provides an easy plug-in/plug-out connection to a compatible cable.

3.3. Installation Accessories

The probe can be installed through a surface using the optional product code 243261SP, or attached for example to a wall with the optional clip accessory (two-clip set, Vaisala product code 243257SP.

More Information

‣

Spare Parts and Accessories (page 78)

ﬂange accessory (Vaisala

GMP252 User Guide M211897EN-B

3.3.1. 243261SP Installation Flange

The optional ﬂange accessory is used to install the probe body through a wall or other surface.

Figure 6 Probe with 243261SP Installation Flange

1 4 Phillips head screws (included) 2 Installation ﬂange (diameter 60 mm) with four Ø 4.2 mm screw holes 3 Gasket ring

Leaving part of the probe body and the cable outside the measurement environment can cause heat conduction that aects the temperature compensation and measurement accuracy.

More Information

‣

243261SP Mounting Flange Dimensions (page 79)

Ø 4.2 mm

Chapter 3 – Installation

3.3.2. 243257SP Mounting Clips

The optional mounting clips (set of two clips) are used to hold the probe in place for example on a wall or other surface. Each clip base attaches to the installation surface with one screw (screw hole Ø 4.2 mm).

Figure 7 Probe in 243257SP Mounting Clips

3.4. Power Supply

The supply voltage range of the probe is 12 ... 30 VDC with the digital output option. If the analog output is used, the supply voltage range is 12 ... 30 VDC for voltage output and 20 ... 30 VDC for current output.

Typical power consumption is less than 0.4 W in continuous operation, and the maximum is

0.5 W.

GMP252 User Guide M211897EN-B

3.5. Wiring

Table 5 M12 Male Connector

Pin# Function Note Cable 223263SP

Wire Colors

1 Power in • With digital output: 12 ... 30 VDC

• With voltage output: 12 ... 30 VDC

• With current output: 20 ... 30 VDC

Typical average power consumption <0.4 W, maximum

0.5 W.

2 RS-485-

or voltage output

3 GND – Blue

4 RS-485 +

or current output

5 Output control Connecting pin #5 to GND (pin #3) forces the probe to

Voltage: 0 ... 5 VDC or 0 ... 10 VDC (default analog output scaling)

Current: 0 … 20 mA or 4 ... 20 mA (default analog output scaling)

analog output mode. If an analog output conﬁguration has not been selected, default 0...10 VDC and 4...20 mA scalings are used. If pin #5 is not connected, the analog or digital output selected when ordering or set later through conﬁguration is used.

Brown

White

Black

Gray

Note that the probe always remains in analog mode when pin #5 is connected to pin #3, and cannot be switched to digital output in this wiring option.

Chapter 4 – Vaisala Industrial Protocol

4. Vaisala Industrial Protocol

4.1. Overview

RS-485 line of the probe provides an implementation of the Vaisala Industrial Protocol that can be used for service and conﬁguration use, or for interfacing with the system to which the probe is integrated. The protocol is a plaintext protocol suitable for use both by human operators and automated systems.

4.2. Serial Interface Settings

Table 6 Default Serial Interface Settings

Property Description/Value

Bit rate 19200

Parity None

Data bits 8

Stop bit 1

Flow control None

4.3. Physical Interface

The physical interface is a non-isolated 2-wire interface. The data lines are RS-485 D- and RS-485 D+. Ground is shared with power supply. The connector is a 5-pin male M12.

More Information

‣

Wiring (page 20)

GMP252 User Guide M211897EN-B

4.4. Connecting with a Computer

• Vaisala USB service cable (order code 242659)

• Computer with:

• Windows operating system

• Terminal application (for example PuTTy, available from www.vaisala.com/

software)

• Free USB port

• Driver for Vaisala USB service cable installed (available on the cable installation media and at www.vaisala.com/software)

The steps below describe how to connect to the probe using the PuTTY terminal application for Windows and a USB computer connection cable. Connecting with a computer allows you to

conﬁgure and troubleshoot your probe using serial line commands.

1. If you have not used the Vaisala USB cable before, install the driver before attempting to use the cable.

2. Connect the USB serial interface cable between your computer and the M12 connector of the probe.

3. Start the PuTTY application.

4. Select Connection > Serial & USB and check that the correct COM port is selected in the Serial or USB line to connect to

ﬁeld. If you are using the PuTTY terminal application supplied by Vaisala, you can press the USB Finder button to open the Vaisala USB Instrument Finder program.

5. Check that the other serial settings are correct for your connection, and change if necessary. Flow control should be set to None unless you have a reason to change it.

Chapter 4 – Vaisala Industrial Protocol

6. Select Terminal. Use the following settings:

• Local Echo Select Force on. This setting ensures that your typing is shown on the session window.

• Send line ends with line feeds (CR+LF) Set to Selected. This setting ensures that all text lines remain visible on the session window.

7. To open the connection window and start using the serial line, select Open.

If PuTTY is unable to open the serial port you selected, it shows you an error message instead. If this happens, restart PuTTY and check the settings.

More Information

‣

Serial Interface Settings (page 21)

‣

Installing the Driver for the USB Service Cable (page 23)

4.4.1. Installing the Driver for the USB Service Cable

Before taking the USB service cable into use for the USB driver on your computer (requires Windows). When installing the driver, you must accept any security prompts that may appear.

1. Check that the USB service cable is not connected. Disconnect the cable if you have already connected it.

2. Insert the media that came with the cable, or download the latest driver from

www.vaisala.com/software.

3. Run the USB driver installation program (setup.exe), and accept the installation defaults. The installation of the driver may take several minutes.

4. After the driver has been installed, connect the USB service cable to a USB port on your computer. Windows will detect the new device, and use the driver automatically.

5. The installation has reserved a COM port for the cable. Verify the port number, and the status of the cable, using the Vaisala USB Instrument Finder program that has been installed in the Windows Start menu. Windows will recognize each individual service cable as a port in the settings of your terminal program.

dierent device, and reserve a new COM port. Remember to use the correct

ﬁrst time, you must install the provided

4.5. Accessing Serial Commands from Modbus or Analog Mode

1. Connect the USB cable to your PC and start the terminal application as instructed in

4.4. Connecting with a Computer (page 22).

GMP252 User Guide M211897EN-B

2. Start a new terminal session using the default serial settings.

3. Keep the Enter key pressed down and connect the probe to the USB cable. When the probe is powered on (connected to your PC with the USB cable), you must send ﬁve carriage returns (Enter key presses) within 0.7 seconds to force the probe to serial command mode. The probe model information appears in the terminal application when the mode has been succesfully changed, and Vaisala Industrial Protocol commands are available for use.

4. To test the connection, enter for example the ? command. If the mode change failed, close the terminal application, disconnect the probe from the USB cable, and repeat

step 2 and step 3.

5. To keep the serial mode in use (forced serial mode access is temporary and switches at reset), select a serial output option (stop/run/poll) with the smode command.

Note that the probe always remains in analog mode when pin #5 is connected to pin #3, and cannot be switched to digital output in this wiring option.

More Information

‣

Serial Interface Settings (page 21)

‣

Enabling Modbus Mode from Vaisala Industrial Protocol (page 24)

4.6. Enabling Modbus Mode from Vaisala Industrial Protocol

If you need to switch from Vaisala Industrial Protocol to Modbus mode, you must the following settings:

• Serial line operating mode

• Modbus address

• Serial line settings (bit rate, parity, stop and data bits)

conﬁgure

o

1. Connect the USB cable to your PC and start the terminal application as instructed in

4.4. Connecting with a Computer (page 22).

2. Set the serial mode to Modbus with the smode command:

smode modbus

Chapter 4 – Vaisala Industrial Protocol

3. Set the Modbus address to 240 with the addr command:

addr 240

4. Set the serial line settings to 19200/N/8/2 with the seri command:

seri 19200 N 8 2

5. Power conﬁguration is available at the next restart.

More Information

‣

Accessing Serial Commands from Modbus or Analog Mode (page 23)

o (disconnect) the probe or reset with the reset command. The new

4.7. Changing From Digital Output to Analog Output

1. Set up a terminal connection as instructed in 4.4. Connecting with a Computer

(page 22).

2. Change the mode from digital to analog with the smode serial command: smode analog.

3. Reset the probe (disconnect and reconnect the cable or use the reset serial command) to power on in analog output mode.

More Information

‣

Accessing Serial Commands from Modbus or Analog Mode (page 23)

4.8. Serial Commands

The notation <cr> refers to the carriage return control character, which you can send in a terminal application by pressing enter on your keyboard. Before entering commands, send a <cr> to clear the command

You can enter the commands in uppercase or lowercase. In the command examples, the keyboard input by the user is in bold type.

Table 7 (page 26) lists the basic serial commands that are available by default. To access

advanced serial commands (listed in Table 8 (page 27)), enter the command pass 1300.

buer.

GMP252 User Guide M211897EN-B

Table 7 Basic Serial Commands

Command Description

Device information and status

errs

help

snum

system

time

vers

Serial line output and communication

form [modifier string]

intv [0 ... 255 s/min/h]

open [address]

Show probe information.

Show probe information (will respond in POLL mode).

Show currently active errors.

Show list of currently available serial commands.

Show probe serial number.

Show probe ﬁrmware information.

Show probe operation hours and uptime.

Show probe ﬁrmware version.

Close connection to probe (POLL mode)

Show or set output format.

Set continuous output interval for R command.

Open connection to probe in POLL mode.

sdelay [0 ... 255]

send

seri [baud data stop parity]

smode [mode]

Environmental compensation

env

Adjustment information

adate

atext

Other commands

Start the continuous outputting.

Stop the continuous outputting.

Show or set serial line transmission delay in milliseconds.

Output a single measurement message.

Show or set the serial interface settings.

Show or set startup serial mode: RUN, STOP, or POLL.

Show or set environmental parameters.

Show CO2 factory adjustment date.

Show CO2 factory adjustment information.

Command Description

Chapter 4 – Vaisala Industrial Protocol

reset

pass [1300]

Reset the probe.

Access advanced serial commands.

Table 8 Advanced Serial Commands

Command Description

Serial line output and communication

addr [0 … 254] Show or set probe address.

Analog output

amode

aover

asel

Calibration and adjustment

cco2

Show or set analog output mode (analog output limits and error level).

Show or set analog output overrange and clipping behavior.

Show or set analog output parameter and scaling.

Adjust CO2 measurement gain and oset.

cdate

ctext

Environmental compensation

o2cmode

pcmode

rhcmode

tcmode

Other commands

frestore

Show or set calibration date.

Adjust temperature measurement oset.

Show or set calibration information.

Show or set oxygen compensation mode.

Show or set pressure compensation mode.

Show or set humidity compensation mode.

Show or set temperature compensation mode.

Restore probe to factory settings.

GMP252 User Guide M211897EN-B

4.9. Device Information and Status

Table 9 ? Command

Syntax Description

?<cr>

??<cr>

Example:

Device : GMP25x Copyright : Copyright (c) Vaisala Oyj 2016. All rights reserved. SW Name : GMP25x SW version : 1.0.0 SNUM : GMP233_5_18 SSNUM : S1234567 CBNUM : c1234567 Calibrated : 20160504 @ Vaisala/R&D Address : 0 Smode : STOP

Show listing of device information.

Show listing of device information even if device is in poll mode and connection has not been opened using the open command.

Table 10 Errs Command

Syntax Description

errs<cr>

Example (no active errors):

errs

NO CRITICAL ERRORS NO ERRORS NO WARNINGS STATUS NORMAL

Show active error(s). For a list of possible errors and their remedies, see 8.2. Error Messages (page 72).

Table 11 Help Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

help<cr>

Example (showing a list of the basic commands):

help

ADATE ADDR ATEXT CLOSE ENV ERRS FORM HELP INTV PASS RR ESET RX SDELAY SEND SENDX SERI SMODE SNUM SYSTEM UNIQID TIME VERS

Show list of currently available serial commands.

Table 12 Snum command

Syntax Description

snum<cr>

Example:

snum

SNUM : M0220028

Show serial number of the probe.

GMP252 User Guide M211897EN-B

Table 13 System Command

Syntax Description

system<cr>

Show probe ﬁrmware information.

Example:

system

Device Name : GMP25x SW Name : GMP25x SW version : 1.0.0 Operating system : TSFOS1.0

Table 14 Time Command

Syntax Description

time<cr>

Example:

Show how long the probe has been in operation since the last startup or reset. The operation counter is in format hh:mm:ss.

time

Time : 01:41:24

Table 15 Vers Command

Syntax Description

vers<cr>

Example:

vers

SW version : 1.0.0

Show ﬁrmware version of the probe.

4.10. Serial Line Output and Communication

Table 16 Addr Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

addr<cr>

addr [aaa]<cr>

Example (shows 0 as current address, enter 5 as the new address):

addr

Address : 0

addr 5

Address : 5

Show current device address. Addresses are required for POLL mode.

Set new device address. aaa = address, 0 ... 254 (default = 0)

Table 17 Close Command

Syntax Description

close<cr> Close the connection that was opened with the open

command.

Example:

line closed

Table 18 Form Command

Syntax Description

form<cr>

form /<cr>

Show the currently used measurement format.

Reset measurement format to default.

GMP252 User Guide M211897EN-B

Syntax Description

form [sss]<cr>

Set a new measurement format. sss = String consisting of modiﬁers and abbreviations for measured parameters. See Table 19 on the facing page and Table 20 on the facing page. Maximum length is 150 characters. Maximum length may be shorter when text strings are used.

Example (show currently used measurement format (default format shown here)):

form

6.0 "CO2=" CO2 " " U3 #r #n

Output example (continuous output from RUN mode):

CO2= 452 ppm

Example (set output format as %CO

form 3.1 "CO2=" CO2% " " U4 #r #n

Output example (continuous output from RUN mode):

CO2= 5.1 %CO2 CO2= 5.1 %CO2 CO2= 5.0 %CO2 ...

Syntax Description

Example (set output format as CO2 ppm with Modulus-65536 checksum):

form 6.0 "CO2=" CO2 " " U3 " " CS4 #r #n

Output example (continuous output from RUN mode):

CO2= 3563 ppm 9F CO2= 3562 ppm 9E CO2= 3559 ppm A4 ...

Chapter 4 – Vaisala Industrial Protocol

Example (set output format as CO

ppm, with start of text (ASCII character 002) and end of text (003) ASCII

codes, and without line feed and carriage return at the end):

form #002 6.0 "CO2=" CO2 " " U3 #003

Output example (continuous output from RUN mode, ASCII codes not visible here):

CO2= 866 ppm CO2= 866 ppm CO2= 867 ppm CO2= 867 ppm CO2= 867 ppm CO2= 868 ppm CO2= 868 ppm CO2= 869 ppm ...

Table 19 Output Parameters for Form Command

Output Parameter Abbreviation in Form Command

Carbon dioxide in ppm

Carbon dioxide in percent

Currently used temperature compensation value

Currently used pressure compensation value

co2

co2%

tcomp

pcomp

GMP252 User Guide M211897EN-B

Output Parameter Abbreviation in Form Command

Currently used oxygen concentration compensation

o2comp

value

Currently used relative humidity compensation value

rhcomp

Table 20 Modiﬁers for Form Command

Modiﬁer Description

x.y

#xxx

addr

Length modiﬁer (number of digits and decimal places).

Tabulator.

Carriage-return.

Line feed.

String constant, length 1 ... 15 characters.

ASCII code value (decimal) of a special character; for example, #027 for ESC.

Probe address (0 ... 254).

time

cs4

csx

Probe serial number.

Cumulative operating hours of the probe.

Name of the measurement unit using x number of characters. For example, u3 shows the name of the measurement unit with three characters.

Modulus-65536 checksum of message sent so far, ASCII encoded hexadecimal notation.

NMEA xor-checksum of message sent so far, ASCII encoded hexadecimal notation.

You can also use the backslash character \ instead of the hash character #.

Table 21 Intv Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

intv<cr>

intv [iii uuu]<cr>

Example:

intv 5 s

Output interval: 5 S

Table 22 Open Command

Show the output interval of the automatically repeating measurement messages (r command and run mode).

Set the output interval. iii = interval, range 0 ... 255. u = unit for interval setting:

• s = seconds

• min = minutes

• h = hours

If you set the interval to 0, the output messages are output as quickly as they are generated, without additional delay.

Syntax Description

open [aaa]<cr>

Open a connection to a device at the speciﬁed address. Required when device is in poll mode. aaa = address, range 0 ... 254.

Example (target probe in POLL mode, with address 52):

open 52

GMP25x: 52 Opened for operator commands

GMP252 User Guide M211897EN-B

Table 23 R Command

Syntax Description

r<cr>

Start the continuous outputting of measurement values as an ASCII text string to the serial line. The probe keeps outputting measurement messages at the interval that has been set with the intv command until stopped with the s command.

Example:

CO2= 1024 ppm CO2= 1024 ppm CO2= 1028 ppm CO2= 1026 ppm CO2= 1028 ppm ...

Table 24 S Command

Syntax Description

s<cr>

Stop the continuous outputting that was started with the r command.

Example:

... CO2= 658 ppm CO2= 654 ppm CO2= 655 ppm

Table 25 Sdelay Command

Syntax Description

sdelay<cr>

sdelay [delay]<cr>

Show serial line transmission delay in milliseconds.

Set a new serial line transmission delay. delay = Serial line delay, range 0 … 255 (milliseconds).

Syntax Description

Example (set delay to 50 milliseconds):

sdelay 50

COM transmit delay : 50

Table 26 Send Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

send<cr>

send [aaa]<cr>

Example:

send

CO2= 1422 ppm

Example (target probe in POLL mode, with address 52):

send 52

CO2= 458 ppm

Output a single measurement message.

Output a single measurement message from a device in poll mode. aaa = address of the probe, range range 0 ... 254

Table 27 Seri Command

Syntax Description

seri<cr>

Show current serial line settings.

GMP252 User Guide M211897EN-B

Syntax Description

seri [b p d s]<cr>

Example (show current settings):

seri

Com1 Baud rate : 19200 Com1 Parity : N Com1 Data bits : 8 Com1 Stop bits : 1

Set new serial line settings. The new settings will be taken into use when the probe is reset or powered up.

b = baud rate (9600, 19200, or 38400) p = parity

• n = none

• e = even

• o = odd

d = data bits (7 or 8) s = stop bits (1 or 2)

For Modbus, baud rate must be 9600 ... 38400 and parity must be none.

Example (set serial line to 9600 baud, even, 7 data bits, and 1 stop bit, and reset the probe to take the new settings in use):

seri 9600 e 7 1

seri

Com1 Baud rate : 9600 Com1 Parity : E Com1 Data bits : 7 Com1 Stop bits : 1

reset

GMP25x 1.0.0

Table 28 Smode Command

Syntax Description

smode<cr>

Show current start-up operating mode of the serial line, and prompt to enter new mode.

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

smode [mode]<cr>

Example (set serial mode to "poll"):

Set serial line start-up operating mode. New mode is taken into use when the device is reset or powered up. Available modes: stop = No automatic output. All commands available. Default mode. run = Automatic output of measurement messages. You can stop the output with the s command, and recontinue with the r command. poll = No automatic output. Will respond to addressed send command and ?? command. You can use other commands after opening a connection using an addressed open command. Use with RS485 buses where multiple probes can share the same line. modbus = Serial line communication uses the Modbus protocol. Serial line commands (Vaisala Industrial Protocol) are not accessible in the Modbus mode. analog = Switches the probe from digital output to analog output (active after probe reset). Serial line commands are not accessible in the analog mode.

smode poll

Serial mode : POLL

4.11. Analog Output

Table 29 Amode Command

Syntax Description

amode [channel]<cr>

Show currently set analog output limits and error level. channel = Analog output channel

• 1 = voltage output (V)

• 2 = current output (mA)

GMP252 User Guide M211897EN-B

Syntax Description

amode [channel lo_value hi_value error_value]<cr>

Set new analog output limits and error output value. channel = Analog output channel

• 1 = voltage output (V)

• 2 = current output (mA)

lo_value = Low limit of the channel. hi_value = High limit of the channel. error_value = Error value of the channel.

Example (show current conﬁguration):

pass 1300 amode 1

Aout 1 range (V) : 0.00 ... 10.00 (error : 0.00)

amode 2

Aout 2 range (mA) : 4.00 ... 20.00 (error : 2.00)

Example (set channel 1 to 0 … 5 V, and error output to 0.0 V; set channel 2 to 0 ... 20 mA, and error output to 23 mA):

amode 1 0 5 0.0

Aout 1 range (V) : 0.00 ... 5.00 (error : 0.00)

amode 2 0 20 23

Aout 2 range (mA) : 0.00 ... 20.00 (error : 23.00)

Table 30 Aover Command

Syntax Description

aover [channel<cr>

Show the behavior of the analog output when the measured value is outside the scaled output range. channel = Analog output channel

• 1 = voltage output (V)

• 2 = current output (mA)

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

aover [channel clipping error_ limit]<cr>

Set the behavior of the analog output when the measured value is outside the scaled output range. channel = Analog output channel

• 1 = voltage output (V)

• 2 = current output (mA)

clipping = Output margin (%) at which the output is clipped. error_limit = Measurement value margin (%) at which the output of the channel goes into the error state. The current or voltage output of the error state is

deﬁned using the amode command.

Example (view currently set analog output overrange behavior on channel 1):

pass 1300 aover 1

Aout 1 clipping :5.00 % Aout 1 error limit :10.00 %

GMP252 User Guide M211897EN-B

Syntax Description

Example (for channel 1):

1. View currently set analog output scaling (asel command), limits and error level (amode command), and overrange behavior (aover command):

pass 1300 asel 1

Aout 1 quantity : CO2(0 ... 2000)

amode 1

Aout 1 range (V) : 0.00 ... 5.00 (error : 0.00)

aover 1

Aout 1 clipping :1.00 % Aout 1 error limit :5.00 %

2. Set analog output overrange clipping to 5 % and error limit to 10 %:

aover 1 5 10

Aout 1 clipping : 5.00 % Aout 1 error limit : 10.00 %

The analog output now behaves like this:

• Clipping is now set to 5.00 %, meaning the voltage output is allowed to vary between 0 ... 5.25 V. The analog channel will output the measurement for 0 ... 2100 ppmCO2, but range 0 ... 5 V remains scaled to

0 ... 2000 ppmCO2.

• Error limit is 10 %, which means the output will show the error state (0 V) when the measured CO concentration is 10 % outside the scaled output range. With the settings above, this will happen if the

measured CO2 concentration is outside range 0 ... 2200 ppmCO2.

• The voltage output will never be above 5.25 V because of clipping: the voltage output is clipped when the output reaches 5.25 V, and if the measured CO2 concentration keeps rising above 2200 ppmCO2,

the output jumps directly to the error state 0 V.

Syntax Description

Output voltage (V)

Time

0.00

In error state at >2200 ppm (2000 ppm + 10%)

5.00

5.25

Clipped at 2100 ppm (2000 ppm + 5%)

Regular measurement

Output clipping limit

Error level

Chapter 4 – Vaisala Industrial Protocol

Figure 8 Example of analog output overrange behavior

The example shown above uses output scaled to 0 ... 5 V and 0 ... 2000 ppmCO2, has error level set to 0 V, clipping set to 5 % overrange, and error limit set to 10 % overrange. CO2 concentrations (ppm) are indicated for the clipping point and error limit point

Table 31 Asel Command

Syntax Description

asel [channel]<cr>

asel [channel] [parameter lowlimit highlimit]<cr>

Show the parameter and scaling of the analog output in ppm. channel = Analog output channel

• 1 = voltage output (V)

• 2 = current output (mA)

Set the parameter and scaling of the analog output.

channel = Analog output channel parameter = Parameter that is output on analog

channel. The only parameter available is CO2 (in ppm).

lowlimit = Lower limit of channel scaling in ppm. Minimum value is -1000000 ppm (= - 100 %). highlimit = High limit of channel scaling in ppm. Maximum value is 1000000 ppm (= 100 %).

GMP252 User Guide M211897EN-B

Syntax Description

Example (for channel 1, show the currently set analog output parameter and scaling):

pass 1300 asel 1

Aout 1 quantity : CO2(0 ... 10000 ppm)

Example (for channel 1, set scaling to 0 ... 4000 ppmCO2):

pass 1300 asel 1 co2 0 4000

Aout 1 quantity : CO2(0 ... 4000 ppm)

4.12. Calibration and Adjustment

CAUTION!

Calibration and Adjustment (page 68). Make sure that the environmental

compensation settings of the probe are properly set for your calibration environment; see 2.4. Environmental Compensation (page 12).

Table 32 Adate Command

Syntax Description

adate<cr>

Example:

adate

Adjustment date : 20150420

Before using the calibration and adjustment commands, read through 7.3.

Show CO2 factory adjustment date.

Chapter 4 – Vaisala Industrial Protocol

Table 33 Atext Command

Syntax Description

atext<cr> Show CO2 factory adjustment information.

Example:

atext

Adjusted at Vaisala/Helsinki

Table 34 Cdate Command

Syntax Description

cdate<cr>

cdate [yyyymmdd]<cr>

Example:

pass 1300 cdate

Calibration date : 20150220

Example (set a new calibration date to June 30, 2015):

cdate 20150630

Calibration date : 20150630

Show calibration date.

Set a new calibration date. yyyymmdd = Year (yyyy), month (mm) and day (dd) of calibration

Table 35 Ctext Command

Syntax Description

ctext<cr>

ctext [text]<cr>

Show calibration information text.

Set a new calibration information text to be shown after the automatic text "Calibrated at".

GMP252 User Guide M211897EN-B

Syntax Description

Example:

pass 1300 ctext

Calibrated at 500 ppm in lab

Example (set a new information text):

ctext 0/1000 by NN

Calibrated at 0/1000 ppm by NN

Table 36 CCO2 Command

Syntax Description

cco2<cr>

cco2 -lo [co2]<cr> cco2 -hi [co2]<cr>

cco2 -save<cr>

cco2 -cancel<cr>

cco2 -reset<cr>

Show current user adjustment status.

Perform a 1-point (only either low or high concentration) or 2-point (both low and high concentrations) calibration and adjustment.

-lo = Adjustment at low concentration (under 1000 ppmCO2)

-hi = Adjustment at high concentration (over 2000 ppmCO2) co2 = CO2 concentration reference in ppm

Save the currently entered adjustments. Successfully saving the adjustment clears the calibration date (cdate command) and calibration text (ctext command) that have been stored in the probe. Use those commands to enter a new calibration date and text.

Cancel currently entered adjustments.

Clear user adjustments.

Syntax Description

Example (show current user adjustment status; no adjustment done):

pass 1300 cco2

1.Ref. point low 0

1.Meas. point low 0

2.Ref. point high 3000

2.Meas. point high 3000 Gain : 1.0000 Offset : 0.0000

Example (perform a 1-point calibration):

1. Let the probe stabilize in the desired CO2 concentration (here: 500 ppmCO2).

2. Enter the calibration commands:

Chapter 4 – Vaisala Industrial Protocol

pass 1300 cco2 -lo 500

cco2 -save

3. Enter a new calibration date and information text:

cdate 20160325

Calibration date : 20160325

ctext 500 ppm in lab

Calibrated at 500 ppm in lab

GMP252 User Guide M211897EN-B

Syntax Description

Example (perform 2-point calibration):

1. Let the probe stabilize in the desired low CO2 concentration (here: 200 ppmCO2).

2. Enter the calibration commands:

pass 1300 cco2 -lo 200

cco2 -save

3. Let the probe stabilize in the desired high CO2 concentration (here: 3000 ppmCO2).

4. Enter the calibration commands:

pass 1300 cco2 -hi 3000

cco2 -save

5. Enter a new calibration date and information text:

pass 1300 cdate 20160425

Calibration date : 20160425

ctext 200/3000 ppm

Calibrated at 200/3000 ppm

4.13. Environmental Compensation Commands

To apply an accurate relative humidity compensation, the temperature and pressure compensation rhcmode, tcmode and pcmode commands for instructions on enabling compensation conﬁguration, and env command for instructions on setting a compensation value.

conﬁgurations must also match your measurement environment. See the

For more information on environmental compensation and the default (neutral) compensation values used for disabled compensations, see 2.4. Environmental

Compensation (page 12)

Table 37 Env Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

env<cr>

env [temp | pres | oxy | hum] [value]<cr>

Show current compensation values. Before using this command, you must enable environmental compensation using the following commands:

• o2cmode [on]

• pcmode [on]

• rhcmode [on]

• tcmode [on | measured]

Set new permanent compensation values and store them in eeprom. Eeprom:

• Non-volatile memory, values retained during power o.

• Number of writes is limited to 30000 cycles by memory implementation.

• Must only be used for writing permanent values, to avoid wearing out the eeprom.

temp = Compensation temperature. Range -40 ... +100 °C. pres = Compensation pressure. Range 500 ... 1100 hPa. oxy = Oxygen content of background gas. Range 0 ... 100 %. hum = Relative humidity of background gas. Range 0 ... 100 %.

GMP252 User Guide M211897EN-B

Syntax Description

env [xtemp | xpres | xoxy | xhum] [value]<cr>

Set new compensation values and store them in RAM. RAM: n Volatile memory that loses the values when probe is reset, and where values are loaded from non-volatile memory at startup. n Must be used for continuously updated values. xtemp = Compensation temperature stored in RAM. Range -40 ... 100 °C. xpres = Compensation pressure stored in RAM. Range 500 ... 1100 hPa. xoxy = Oxygen content of background gas stored in RAM. Range 0 ... 100 %. xhum = Relative humidity of background gas stored in RAM. Range 0 ... 100 %.

Note: If temperature compensation is conﬁgured to use an internally measured value (tcmode is set to measured), it will continuously update the value in RAM, overriding any temperature value that is written to RAM with the ENV command.

Example (Show current compensation values; all compensations are enabled. Note that temperature compensation is in "measured" mode, so the value in use is constantly changing):

env

In eeprom: Temperature (C) : 8.00 Pressure (hPa) : 1013.00 Oxygen (%O2) : 21.00 Humidity (%RH) : 30.00

In use: Temperature (C) : 4.90 Pressure (hPa) : 1013.00 Oxygen (%O2) : 19.70 Humidity (%RH) : 27.00

Chapter 4 – Vaisala Industrial Protocol

Syntax Description

Example (set temperature compensation to setpoint mode, and change temperature setpoint value to

5.00 °C in RAM):

pass 1300 tcmode on

T COMP MODE : ON

env xtemp 5.00

In eeprom: Temperature (C) : 8.00 Pressure (hPa) : 1013.00 Oxygen (%O2) : 21.00 Humidity (%RH) : 30.000

In use: Temperature (C) : 5.00 Pressure (hPa) : 1013.00 Oxygen (%O2) : 21.00 Humidity (%RH) : 30.00

Table 38 O2cmode Command

Syntax Description

o2cmode<cr>

o2cmode [on | off]<cr>

Example (check oxygen compensation mode; oxygen compensation is disabled, a neutral value is used):

pass 1300 o2cmode

O2 COMP MODE : OFF

Check current oxygen compensation mode. Possible modes:

• on = Compensation enabled using setpoint value.

• off = Compensation disabled, default (neutral) value used: see 2.4. Environmental

Compensation (page 12)

Change oxygen compensation mode (on or off).

GMP252 User Guide M211897EN-B

Syntax Description

Example (enable oxygen compensation):

pass 1300 o2cmode on

O2 COMP MODE : ON

Table 39 Pcmode Command

Syntax Description

pcmode<cr> Check current pressure compensation mode.

Possible modes:

• on = Compensation enabled using setpoint value.

• off = Compensation disabled, default (neutral) value used: see 2.4. Environmental

Compensation (page 12).

pcmode [on | off]<cr>

Change pressure compensation mode (on or off).

Example (check pressure compensation mode; pressure compensation is enabled using a setpoint value):

pass 1300 pcmode

P COMP MODE : ON

Table 40 Rhcmode Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

rhcmode<cr>

Check current relative humidity compensation mode. Possible modes:

• on = Compensation enabled using setpoint value.

• off = Compensation disabled, default (neutral) value used: see 2.4. Environmental

Compensation (page 12).

To apply an accurate relative humidity compensation, make sure that the temperature compensation and pressure compensation conﬁgurations also match the measurement environment.

rhcmode [on | off]<cr>

Change relative humidity compensation mode (on or off).

Example (check relative humidity compensation mode; relative humidity compensation is disabled, a neutral value is used):

pass 1300 rhcmode

RH COMP MODE : OFF

Example (enable temperature, pressure and relative humidity compensation using setpoint values):

pass 1300 tcmode on

T COMP MODE : ON

pcmode on

P COMP MODE : ON

rhcmode on

RH COMP MODE : ON

GMP252 User Guide M211897EN-B

Table 41 Tcmode Command

Syntax Description

tcmode<cr>

Check current temperature compensation mode. Possible modes:

• on = Compensation enabled using setpoint value.

• off = Compensation disabled, default (neutral) value used: see 2.4. Environmental

Compensation (page 12)

• measured = Compensation enabled using internal measurement.

tcmode [on | off | measured]<cr>

Change temperature compensation mode (on, off or measured).

Example (check temperature compensation mode; temperature compensation is enabled using a setpoint value):

pass 1300 tcmode

T COMP MODE : ON

Example (change temperature compensation to use internal measurement):

pass 1300 tcmode measured

T COMP MODE : MEASURED

4.14. Other Commands

Table 42 Frestore Command

Syntax Description

Chapter 4 – Vaisala Industrial Protocol

frestore<cr>

Example (restore the factory settings and reset the probe):

pass 1300 frestore

Parameters restored to factory defaults

reset

GMP25x 1.0.0

Table 43 Pass Command

Restore the probe to its factory conﬁguration. All user settings and user calibration parameters will be lost.

After using the frestore command, reset the probe using the reset command.

Syntax Description

pass [code]<cr>

Example:

pass 1300

Access advanced serial commands. Advanced commands can be used until the next reset. code = Code for enabling advanced commands (1300).

GMP252 User Guide M211897EN-B

Table 44 Reset Command

Syntax Description

reset<cr>

Example:

reset

GMP25x 1.0.0

Reset the probe. The probe will restart as if it had just been powered on.

Chapter 5 – Modbus

5. Modbus

The probe can be accessed using the Modbus serial communication protocol. The supported Modbus variant is Modbus RTU (Serial Modbus) over RS-485 interface.

For instructions on enabling the Modbus mode when you are using the probe with Vaisala Industrial Protocol, see 4.6. Enabling Modbus Mode from Vaisala Industrial Protocol

(page 24).

For instructions on switching to Vaisala Industrial Protocol when the probe is in Modbus mode, see 4.5. Accessing Serial Commands from Modbus or Analog Mode (page 23).

The

pre-conﬁgured default Modbus serial settings are presented in the following table.

Table 45 Default Modbus Serial Communication Settings

Description Default Value

Serial bit rate 19200

Parity N

Number of data bits 8

Number of stop bits 2

Modbus device address 240

More Information

‣

Function Codes (page 81)

‣

Modbus Registers (page 81)

GMP252 User Guide M211897EN-B

6. Operating with MI70 Indicator

6.1. Overview of MI70 Support

The probe is compatible with instruments that utilize the MI70 indicator, for example the GM70 Hand-Held Carbon Dioxide Meter. The MI70 indicator is a convenient service tool for viewing the measurement readings, adjusting the environmental compensation settings, and performing calibration and one-point adjustment.

When MI70 is used with GMP252, it is recommended to use the rechargeable battery pack instead of alkaline batteries due to the relatively high power usage in CO2 measurement.

6.2. Basic Display

Figure 9 MI70 Basic Display

1 Measured parameter and compensations

(up to three items on display simultaneously).

2 Battery indicator. Shows current status

(charge) of the battery.

3 Function key Graphic shows the readings

as a curve.

4 Function key Hold/Save freezes the

display and you can save the reading in the MI70 memory.

5 Function key Record is a quick access to

the Recording/Viewing menu.

You can change the shown items in Main menu > Display > Quantities and units.

You can change the default function key shortcuts (Graphic, Hold/Save, Record) to other menus or functions in Main menu > Settings > User interface > Program shortcut keys.

Chapter 6 – Operating with MI70 Indicator

6.3. Graphical Display

The graphical display shows you the measurements as a curve (the curve of the uppermost quantity shown in the basic display). From the curve you can examine the data trend and history of the last minutes.

To open the graphical display, select Graphic in the basic display or select Main menu > Display > Graphic history > Show.

To get the statistical info on the graph area (minimum, maximum, and average values), press Info.

To get the curve of the other selected quantities, press Next. To get the curves of all the quantities, press Next until the text All appears, and then select All .

To zoom in and out, press the up/down arrow keys.

To move back and forward in the timeline, use the left/right arrow keys.

6.4. Main Menu

In the main menu, you can information about the probe, access recordings and clear the memory, set alarms, start adjustments, and use the analog output option of the MI70 indicator.

To open the main menu and navigate in the menus:

1. Go to the basic display.

Press any arrow key, then select Open (must be pressed within 5 seconds or the indicator returns to the basic display).

Move in the menus using the

Select an item with the button.

To return to the previous level, press .

To return to normal operation, press

conﬁgure the MI70 settings and basic display options, view

buttons.

Exit.

6.5. Connecting Probe to MI70 Indicator

1. If the probe is installed permanently into a device (for example, an incubator or a chamber), disconnect the probe from the connector.

2. If the MI70 indicator is on, turn it

o.

3. Connect the probe to the MI70 indicator using the MI70 connection cable (Vaisala order code: CBL210472).

4. Turn on the MI70 indicator (time and date are requested at ﬁrst startup). MI70 detects the probe and proceeds to show the measurement screen. The parameters measured by probe will start to show valid measurement results after a few seconds.

GMP252 User Guide M211897EN-B

6.6. MI70 Indicator Parts

Figure 10 MI70 Indicator Parts

1 Charger socket 2

Function buttons . The functions change according to what you are doing with the indicator.

3 Arrow buttons:

Move up in a menu Move down in a menu Enter a sub-menu

Return to previous menu level

4 Power On/O button 5 Battery compartment at the back of the

indicator

6 Two ports (labeled I and II) for

connecting probes and instruments.

To open menus, press an arrow button and then press the shortcut buttons. To activate a function shown above the shortcut button, press the shortcut button. To navigate in the menus, press arrow buttons.

6.7. Holding and Saving the Display

With the Hold/Save function, you can freeze a certain display reading. This reading can be saved in the MI70 memory and it will be available even after MI70 is disconnected from the transmitter.

1. In the basic display, select Hold/Save. Alternatively, select Main menu > Display > Hold/Save display > Hold.

2. Press Save.

3. To view the saved display, go to basic display and select Record > View recorded data. Alternatively, select Main menu > Recording/Viewing > View recorded data. A list of saved displays and data recordings appears. The icons on the left of the date and time indicate whether the

Saved display

Data recording

ﬁle is a saved display or a longer recording of data:

Chapter 6 – Operating with MI70 Indicator

4. Select the saved display based on date and time by pressing the right arrow key.

6.8. Recording Data

With MI70, you can record transmitter measurement data over a certain period at chosen intervals. These recordings are saved in MI70 memory and are available even after MI70 is disconnected from the transmitter.

Starting and Stopping the Recording

You can record the measurement of the parameters that are currently shown on the MI70 basic display. You can change the shown parameters in Main menu > Display > Quantities and units.

1. In the basic display, select Record > Record data. Alternatively, select Main menu > Recording/Viewing > Record data.

2. If needed, change the interval and duration of the recording in the RECORD DATA view. The measurement intervals and maximum recording times are shown in the following table.

If you set the duration to "Memory full", the recording continues until the MI70 memory is full or until you stop the recording manually. The maximum recording time is shown when you start the recording.

3. Select Start/Stop recording > Start. The recording continues until the duration has passed or until you stop the recording manually. You can switch the MI70

o during recording to save battery. A progress bar is shown on the display every 10 seconds (or all the time, if a charger is connected). The progress bar shows the amount of recorded data.

CAUTION!

indicator is o. This may cause loss of recorded data.

Do not disconnect the probe when the data recording is on, even if the

GMP252 User Guide M211897EN-B

4. To stop the recording manually, in the basic display select Record > Record data > Start/stop recording > Stop. To view the recorded ﬁle, select Show.

6.9. Changing Environmental Compensation Settings with MI70 Indicator

You can see the compensation values that are currently used by the probe by selecting them as display quantities from Main menu > Display > Quantities and Units. The quantities are as follows:

• Tcomp: currently active temperature compensation value.

• Pcomp: currently active pressure compensation value.

• Ocomp: currently active oxygen concentration compensation value.

• Hcomp: currently active relative humidity compensation value.

Figure 11 CO2 Reading with Tcomp and Pcomp on MI70 Screen

You can change the compensation settings from Main menu > Settings > Measurement settings. For more information about the possible settings and their meaning, see 2.4.

Environmental Compensation (page 12).

Figure 12 Probe Compensation Settings on MI70 Screen

When you turn a compensation display quantity (for example, Pcomp shows 1013.2 hPa). This is the default compensation value that is mathematically neutral for the probe’s internal compensation model.

o, the probe still shows a value for the corresponding

Chapter 6 – Operating with MI70 Indicator

6.10. Calibration and Adjustment with

MI70 Indicator

Before using the MI70 indicator for calibration and adjustment, read the instructions in 7.3.

Calibration and Adjustment (page 68). Make sure that the environmental compensation

settings of the probe are properly set for your calibration environment; see 6.9. Changing

Environmental Compensation Settings with MI70 Indicator (page 62).

When two probes are connected to the MI70 indicator, MI70 uses Roman numerals “I” and “II” to indicate which port the parameter or function in question is connected to.

6.10.1. 1-Point Adjustment with an MI70-Compatible Reference

Probe

1. Connect the GMP252 probe to Port I of the MI70 indicator.

2. Connect the calibrated reference probe to Port II. Make sure the reference probe is in the same environment as GMP252's sensor.

3. If you are using the calibration adapter to feed a calibration gas to GMP252, you must feed the same gas to the reference probe as well. Refer to the documentation of your reference probe on how to do this and what accessories you need.

4. Turn on the MI70 indicator.

5. Start the adjustment sequence from Main menu > Functions > Adjustments.

6. MI70 notiﬁes you that automatic power o is disabled during adjustment mode, press OK to acknowledge.

7. To proceed with the adjustment, select the CO2(I) parameter in the Select Quantity screen. In the Select Quantity screen you can also view the currently used compensation values, and the Last adjustment date information. You can update the date and text using the CDATE and CTEXT commands on the serial line.

GMP252 User Guide M211897EN-B

8. You may be prompted to check the environmental settings of the reference probe before proceeding. Press Yes to check the settings and Exit when you have checked and corrected the settings.

9. The adjustment mode is now active, and you can see the measured CO2 readings and their dierence on the screen. Allow the measurement to stabilize. To proceed with the

adjustment, press Adjust.

10. Select To same as CO2(II).

11. You will be prompted to conﬁrm you want to adjust: select Yes.

12. If the adjustment is successful, MI70 will show the text Adjustment Done, after which you will return to the adjustment mode. At this point you can press Back and Exit to leave the adjustment mode. The adjustment is now completed. If the adjustment cannot be applied, MI70 will show the text Cannot adjust, possibly followed by a text stating the reason. A possible reason for an adjustment failure is attempting to apply a very large correction to the reading.

6.10.2. 1-Point Adjustment with a Reference Gas

1. Connect GMP252 to Port I of the MI70 indicator.

2. Feed a calibration gas to the GMP252 using the calibration adapter accessory (Vaisala order code: DRW244827SP). If you are using ambient air as the calibration gas, you must have a reference meter in the same environment to verify the CO2 concentration.

3. Turn on the MI70 indicator.

Chapter 6 – Operating with MI70 Indicator

4. Start the adjustment sequence from Main menu > Functions > Adjustments.

5. MI70 notiﬁes you that automatic power o is disabled during adjustment mode, press OK to acknowledge.

6. Select the CO2 parameter when prompted.

7. You may be prompted to check the environmental settings of the reference probe before proceeding. Press Yes to check the settings and Exit when you have checked and corrected the settings.

8. The adjustment mode is now active, and you can see the measured CO2 reading on the screen. To proceed with the adjustment, press Adjust.

9. Select 1-point adjustment.

10. You will be prompted if you really want to adjust. Select Yes.

11. You are now in the 1-point adjustment screen. Allow the measurement to stabilize and press Ready.

GMP252 User Guide M211897EN-B

12. Enter the CO2 concentration of the reference gas and press OK.

13. You will be prompted if you really want to adjust. Select Yes.

14. If the adjustment is successful, MI70 will show the text Adjustment Done, after which you will return to the adjustment mode. At this point you can press Back and Exit to leave the adjustment mode. The adjustment is now completed. If the adjustment cannot be applied, MI70 will show the text Cannot adjust, possibly followed by a text stating the reason. A possible reason for an adjustment failure is attempting to apply a very large correction to the reading.

Chapter 7 – Maintenance

7. Maintenance

7.1. Cleaning

You can clean the probe body by wiping it with a moist cloth. Standard cleaning agents can be used.

When cleaning, follow these precautions:

• Do not immerse the probe in liquid to clean it.

• Be careful not to block the ﬁlter is especially sensitive to blockage.

• When changing the and ﬁlter material from the sensor. Do not attempt to clean the optical surfaces in any other manner.

ﬁlter, you can use clean instrument air to gently blow any loose dirt

7.1.1. Chemical Tolerance

ﬁlter when cleaning the probe. The optional sintered PTFE

The following chemicals can be used to clean the probe:

• H2O2 (2000 ppm), non-condensing

• Alcohol-based cleaning agents such as ethanol and IPA (70 % Isopropyl Alcohol, 30 % water)

• Acetone

• Acetic acid

Avoid exposing the probe to chemicals for unnecessarily long periods of time. Do not immerse the probe in a chemical, and wipe chemicals

o the probe after cleaning.

GMP252 User Guide M211897EN-B

7.2. Changing the Filter

Change the ﬁlter to a new one if it shows visible signs of contamination or dirt. When changing the ﬁlter, use clean gloves to avoid blocking the pores of the new ﬁlter.

Figure 13 Opening the Filter

CAUTION!

any loose dirt and surfaces in any other manner.

When changing the

ﬁlter material from the sensor. Do not attempt to clean the optical

ﬁlter, you can use clean instrument air to gently blow

7.3. Calibration and Adjustment

Calibrate and adjust the CO2 measurement of the probe as needed. Before starting, read through this section completely so that you are aware of your options, and the main factors

that

aect the result.

Performing an accurate calibration and adjustment takes some time and preparation. Instead of doing it yourself, you can also have a Vaisala Service Center calibrate and adjust your probe.

Calibration means comparing the measurement output of the device to a known reference, such as a known environment in a calibration chamber or the output of a reference instrument. Correcting the reading of the device so that is measures accurately is referred to as adjustment.

Chapter 7 – Maintenance

7.3.1. Calibration Setup

Using Hand-Held Meter as Reference

You can perform a 1-point calibration using a hand-held meter as a reference. You will need a calibrated reference instrument to compare against, for example a GM70 hand-held meter with a calibrated GMP222 probe.

With the probe and the reference instrument in the same space, allow the measurement to stabilize before comparing the readings. Try to provide as stable an environment as you can during this time. Avoid working around the probe and reference instrument during this time.

Using Calibration Gas as Reference

There are two easy ways to use a calibration gas as a reference:

• You can supply the gas to the probe using the calibration adapter accessory (Vaisala order code DRW244827SP). Gas recommendation is 1 l/min. Allow the measurement to stabilize for three minutes before starting the calibration.

• You can

ﬁll the entire incubator with the calibration gas. You can use calibration gas a

reference by putting the probe in a suitable chamber (for example, an incubator) and

ﬁlling that chamber with the calibration gas.

ﬂow should be in the range 0.5 ... 1.1 l/min,

To perform a two-point adjustment, you need two calibration gases: one gas that is below 1000 ppmCO2 (low-end reference) and one that is above 2000 ppmCO2 (high-end

reference).

When supplying the gas from a gas bottle, make sure the gas bottle has stabilized to room temperature before starting.

7.3.2.

Eect of Environmental Compensations

The probe has various environmental compensations that improve its CO2 measurement accuracy (see 2.4. Environmental Compensation (page 12)). As the calibration and

adjustment environment may

dier from the actual measurement environment, you must make sure that the compensation settings are properly set. Here are some key points to remember:

• Pressure and temperature compensations have a signiﬁcant eect on accuracy. If you are using setpoint values instead of the values from the builtin temperature sensor or an integrated system, make sure to correct the setpoints so that they correspond to your calibration situation. Consider switching temperature compensation to use the internal sensor and/or integrated system when calibrating, and then switching back when calibration and adjustment is done.

• The

eect of background gas compensations for humidity and oxygen may be

signiﬁcant when using calibration gases, since these gases are often dry and oxygen-

free. For example, pure nitrogen gas is typically used as a convenient 0 ppm CO

reference. As it does not contain any oxygen or humidity, the compensations for them must be set to zero.

GMP252 User Guide M211897EN-B

• Remember to restore the normal compensation settings after completing calibration and adjustment. If you are integrating the calibration functionality of the probe as part of a control software, also implement proper handling of the environmental compensations.

7.3.3. Limits of Adjustment

The probe limits the amount of adjustment that is allowed to the CO2 measurement. The maximum correction that you can apply is 1000 ppm + 25 % of the probe’s uncorrected

reading. Previous user adjustments do not

aect this limit (the correction is not cumulative).

This feature limits the possible error introduced by incorrect adjustment.

For example, if you are adjusting using a 5000 ppmCO2 calibration gas, the maximum correction you can apply is approximately 2250 ppm. Attempting to apply a greater

adjustment will fail. Notiﬁcation of failure from the probe depends on the interface you are using for adjustment.

7.3.4. Adjustment Types

You can adjust the CO2 measurement of the probe in one or two points.

• One-point adjustment is recommended if you are interested in maintaining a ﬁxed CO

level. For best result, use a calibration gas with a CO2 concentration that is close to the intended level.

• Two-point adjustment is recommended if you typically measure a variable CO2 level.

Available adjustment functions depend on the interface you use to operate the probe. If you want to integrate the functionality into a control system, the Modbus interface and the Vaisala industrial protocol are recommended. If you want to compare the reading of the probe to a reference instrument and adjust it accordingly, use an MI70 hand-held indicator and a reference probe.

Vaisala Industrial Protocol

Vaisala industrial protocol supports one and two-point adjustment with the cco2 command. Conﬁguration of the environmental compensation settings can be done using serial line commands.

Modbus

The environmental compensation settings can be conﬁgured using Modbus registers.

MI70 Hand-Held Indicator

MI70 hand-held indicator supports one-point adjustment, either using a calibration gas or using a reference instrument that is connected to the MI70.

Chapter 7 – Maintenance

7.3.5. DRW244827SP Calibration Adapter

The optional calibration adapter accessory can be used to feed a reference gas to the probe through a gas port when calibrating. Gas ﬂow should be in the range 0.5 ... 1.1 l/min, recommendation is 1 l/min. Allow the measurement to stabilize for three minutes before starting the calibration.

Figure 14 DRW244827SP Calibration Adapter with Probe Inserted

1 O-ring inside the adapter 2 Gas outlet on each side of the adapter 3 Gas port (port outer diameter 4.6 mm, port hole inner diameter 2 mm, suitable for

tubing with 4 mm inner diameter)

GMP252 User Guide M211897EN-B

8. Troubleshooting

8.1. Problem Situations

Problem Possible Cause Remedy

Analog output reading is unchanging and appears incorrect.

Probe outputs stars "****" on serial line instead of measurement data.

Unable to access probe on the RS-485 line.

CO2 measurement not working. Condensation on the sensor. Remove the ﬁlter and check if

Analog output is in error state. Remove the cause of the error

state and the analog output will recover its normal function.

Incorrect supply voltage. Check the power supply.

Check the active errors using the ERRS command on the serial line.

Unsuitable operating environment.

Incorrect wiring. Check that the RS-485 connection

Probe in POLL mode with unknown address.

Verify that the operating environment is within speciﬁed operating limits.

is wired correctly.

Power cycle or reset the probe and try again.

condensation has formed on the sensor. If yes, dry out the condensation with instrument air and insert a new dry ﬁlter. Keep the probe powered and operating to prevent re-occurrence.

More Information

‣

Wiring (page 20)

‣

Analog Output Error State (page 74)

8.2. Error Messages

The error messages are categorized according to the severity of the status:

• Critical errors are fatal to the operation of the unit. It may not be able to respond to communication at all, and will not measure correctly.

• Errors prevent CO2 measurement and cause the analog outputs to be set to the error state. Depending on the problem, errors may resolve themselves. For example, sensor

heating will eventually dry out condensation on the optical surfaces.

• Warnings do not prevent normal operation but may indicate possible problems.

• Status indicates a known state of the unit.

Chapter 8 – Troubleshooting

Error Message Description Recommended Action

Critical errors

Program memory crc critical error Program memory is corrupted. Fatal error, contact Vaisala.

Parameter memory crc critical

Parameter memory is corrupted. Fatal error, contact Vaisala.

error

Errors

Low supply voltage error Check supply voltage.

Internal 30 V error Low internal 30 V voltage.

Low RX signal error Low input signal. Can be caused

by dirt or condensation on the

Wait to see if condensation is removed by heat.

optical surfaces.

Internal 8 V error Low internal 8 V voltage.

RX signal cut error Signal distortion (EMC

interference)

Out of measurement range error CO2 concentration is too high to

measure.

Sensor heater error Sensor heater resistance is out of

Wait for CO2 concentration to fall into the measurable range.

range.

IR temperature error IR source temperature error.

FPI slope error Signal receiver error. Contact Vaisala.

Internal 2.5 V error Internal 2.5 V voltage out of

range.

Internal 1.7 V error Internal 1.7 V voltage out of range.

Low IR current error IR source failure. Contact Vaisala.

Warnings

Signal too low warning Low input signal. Can be caused

Continue normally. by dirt or condensation on the optical surfaces.

Cut warning EMC interference error limit

approaching.

Unexpected restart detected Transmitter is reset by watchdog

Check for EMC interference

sources.

Continue normally. process.

Status messages

CO2 adjustment mode active Complete the CO2 adjustment.

GMP252 User Guide M211897EN-B

8.3. Analog Output Error State

The probe sets the analog output channel into a deﬁned error level instead of the measured result in two situations:

• Probe detects a measurement malfunction. This means an actual measurement problem, such as sensor damage or unsuitable environmental conditions.

• Measured value(s) are

The default error level depends on the output type:

Output Default Error Level

0 ... 20 mA 23 mA

4 ... 20 mA 2 mA

0 ... 5 V 0 V

0 ... 10 V 0 V

signiﬁcantly outside the scaled output range.

The probe resumes normal operation of the analog output when the cause of the error state is removed.

More Information

‣

Analog Output Overrange Behavior (page 14)

9. Technical Data

9.1. GMP252 Speciﬁcations

Table 46 Performance

Property Speciﬁcation

Chapter 9 – Technical Data

Measurement range 0 ... 10 000 ppmCO

(up to 30 000 ppmCO2 with reduced accuracy)

Accuracy at 25 °C and 1013 hPa (incl. repeatability and nonlinearity)

0 ... 3000 ppmCO

3000 ... 10 000 ppmCO

Up to 30 000 ppmCO

±40 ppmCO

±2% of reading

±3.5% of reading

Calibration uncertainty

at 2000 ppmCO

at 10 000 ppmCO

±18 ppmCO

±66 ppmCO

Long-term stability

0 ... 3000 ppmCO

3000 ... 6000 ppmCO

6000 ... 10 000 ppmCO

±60 ppmCO2/year

±150 ppmCO2/year

±300 ppmCO2/year

Temperature dependence 0...10 000 ppmCO

with compensation, -10 ... +50 °C ±0.05% of reading/°C

with compensation, -40 ... +60 °C <±0.1% of reading/°C

without temperature compensation at

-0.5% of reading/°C

2000 ppmCO2 (typical)

Pressure dependence

with compensation at

±0.015% of reading/hPa

0 ... 10 000 ppmCO2, 500...1100 hPa

without compensation (typical) +0.15% of reading/hPa

GMP252 User Guide M211897EN-B

Property Speciﬁcation

Humidity dependence

with compensation,

±0.7% of reading (at 25 °C)

0 ... 10 000 ppmCO2, 0 ... 100 %RH

without compensation (typical) +0.05 % of reading/%RH

O2 dependence

with compensation, 0 ... 10 000 ppm%CO2, 0 ... 90 %O

±0.6 % of reading (at 25 °C)

without compensation (typical) -0.08 % of reading/%O

Start-up, warm-up and response time

Start-up time at 25 °C < 12 s

Warm-up time for full spec. < 2 min

Response time (T90) with standard ﬁlter < 1 min

Table 47 Operating Environment

Property Speciﬁcation

Operating temperature of CO2 measurement -40 ... +60 °C

Storage temperature -40 ... +70 °C

Humidity 0...100 %RH, non-condensing

Condensation prevention Sensor head heating when power on

Electromagnetic compatibility EN61326-1, Generic Environment

Chemical tolerance (temporary exposure during cleaning)

• H2O2 (2000 ppm, non-condensing)

• Alcohol-based cleaning agents (for example ethanol and IPA)

• Acetone

• Acetic acid

Pressure

Compensated 500 ... 1100 hPa

Operating < 1.5 bar

Chapter 9 – Technical Data

Table 48 Inputs and Outputs

Property Speciﬁcation

Digital output Over RS-485:

• Modbus

• Vaisala Industrial Protocol

Analog outputs • 0 ... 5/10 V (scalable), min load 10 kΩ

• 0/4 ... 20 mA (scalable), max load 500 Ω

Operating voltage

With digital output in use 12 ... 30 VDC

With voltage output in use 12 ... 30 VDC

With current output in use 20 ... 30 VDC

Power consumption

Typical (continuous operation) 0.4 W

Maximum 0.5 W

Table 49 Mechanics

Property Speciﬁcation

Weight, probe 58 g

Connector type M12 5-pin male

Housing classiﬁcation, probe body IP65

Materials

Probe housing material PBT plastic

Filter PTFE

Connector Nickel plated brass

Dimensions

Probe diameter 25 mm

Probe length 130 mm

12 mm 76 mm 42 mm

130 mm, Ø 25 mm

GMP252 User Guide M211897EN-B

9.2. Spare Parts and Accessories

Information on spare parts, accessories, and calibration products is available online at

www.vaisala.com and store.vaisala.com.

Name Order Code

Porous sintered PTFE ﬁlter for GMP252 DRW244221SP

Probe cable with open wires (1.5 m) 223263SP

Probe cable with open wires and 90° plug (0.6 m) 244669SP

Probe cable with open wires (10 m) 216546SP

USB cable for PC connection 242659

MI70 connection cable for probe CBL210472

Flat cable for GMP250 probes, M12 5-pin CBL210493SP

Probe mounting clips (2 pcs) 243257SP

Probe mounting ﬂange 243261SP

Calibration adapter DRW244827SP

9.3. GMP252 Probe Dimensions

The dimensions are given in millimeters (mm).

Figure 15 GMP252 Dimensions

9.4. 243261SP Mounting Flange

Ø 4.2

35.4

5 17

Ø 36

Ø 60

Ø 25.6 Ø 28.5

Ø 42

Dimensions

Chapter 9 – Technical Data

Figure 16 243261SP Mounting Flange Dimensions

Figure 17 243261SP Mounting Flange Dimensions, Cross Section

GMP252 User Guide M211897EN-B

9.5. 243261SP Calibration Adapter Dimensions

Figure 18 243261SP Calibration Adapter Dimensions

Appendix A – Modbus Reference

Appendix A. Modbus Reference

A.1. Function Codes

Table 50 Supported Function Codes

Function Code (Decimal) Function Code (Hexadecimal) Name

03 03 Read Holding Registers

16 10 Write Multiple Registers

43 14 2B 0E Read Device Identiﬁcation

A.2. Modbus Registers

CAUTION!

(the register addresses start from 1). Note that the register addresses in actual Modbus messages (Modbus Protocol Data Unit (PDU)) start from zero. Subtract 1 from the decimal addresses presented in this manual to get the address used in the Modbus message (for example, the decimal register address 1 (Measured CO2 value) becomes

Accessing unavailable (temporarily missing) measurement data does not generate an exception. “Unavailable” value (a quiet NaN for data) is returned instead. An exception is generated only for any access outside the applicable register ranges.

A.2.1. Measurement Data

Table 51 Modbus Measurement Data Registers (Read-Only)

Address (Decimal)

Address (Hexadecimal)

The decimal numbering of register addresses used in this manual is 1-based

ﬂoating point data or 0x0000 for integer

1 00 00 Measured CO2 value 32-bit ﬂoat ppm

3 00 02 Compensation T 32-bit ﬂoat °C

GMP252 User Guide M211897EN-B

Address (Decimal)

5 00 04 Measured T 32-bit ﬂoat °C

257 01 00 Measured CO2 value 16-bit signed

258 01 01 Measured CO2 value 16-bit signed

1) The ppm output of the second Measured CO2 value register (address 258) is scaled and must be multiplied by 10.

Address (Hexadecimal)

ppm (up to 32 000

integer

ppm)

ppm1) (scaled, up to approx. 320 000 ppm)

A.2.2. Conﬁguration Registers

CAUTION!

EEPROM memory. The EEPROM memory implementation has a limit of 30000 writes, and is intended to be used only when saving long-term or permanent conﬁgurations. Use the volatile memory (registers 521-527, values cleared on power-up) for nonpermanent updates the compensation values).

Default power-up values (registers 513-519) are written into non-volatile

conﬁgurations (for example, if the probe is used in a system that regularly

Table 52 Modbus Conﬁguration Data Registers (Writable)

Address (Decimal)

513 02 00 Power-up value for

515 02 02 Power-up value for

517 02 04 Power-up value for

519 02 06 Power-up value for

521 02 08 Volatile (value cleared

Address (Hexadecimal)

Format

32-bit ﬂoat hPa pressure compensation

32-bit ﬂoat °C temperature compensation

32-bit ﬂoat %RH humidity compensation

32-bit ﬂoat %O oxygen compensation

32-bit ﬂoat Range 700...1500 hPa at probe reset) pressure compensation

Unit / Valid Range

700 ... 1500 hPa Operating <1.5 bar (Init/default: 1013.25)

-40 ... +80 (Init/default: 25)

0 ... 100 % (Init/default: 0)

(Init copied from power-up value)

Appendix A – Modbus Reference

Address (Decimal)

523 02 0A Volatile (value cleared

Address (Hexadecimal)

Format

32-bit ﬂoat Range -40...+80 °C at probe reset) temperature

Unit / Valid Range

(Init copied from power-up value)

compensation

525 02 0C Volatile (value cleared

at probe reset) humidity

32-bit ﬂoat Range 0...100 %RH

(Init copied from power-up value)

compensation

527 02 0E Volatile (value cleared

at probe reset) oxygen compensation

769 03 00 Modbus address 16-bit

32-bit ﬂoat Range 0...100 %O

(Init copied from power-up value)

Valid range 1...247 (default:

integer

240)

770 03 01 Serial speed enum Valid range 4800...115200

0 = 4800 1 = 9600 2 = 19200 3 = 38400 4 = 57600 5 = 115200 (default: 2 (19200))

771 03 02 Serial parity enum 0 = None

1 = Even 2 = Odd (default: 0 (None))

772 03 03 Serial stop bits 16-bit

integer

773 03 04 Pressure

enum 0 = O compensation mode

Valid range 1...2 (default: 2)

1 = On (default: 1 (On))

774 03 05 Temperature

compensation mode

enum 0 = O

1 = Given 2 = Measured (default: 2 (Measured))

775 03 06 Humidity

compensation mode

enum 0 = O

1 = On (default: 0 (O))

776 03 07 Oxygen compensation

mode

enum 0 = O

1 = On (default: 0 (O))

GMP252 User Guide M211897EN-B

Address (Decimal)

777 03 08 CO2 ﬁltering factor 16-bit

Address (Hexadecimal)

Format

integer

Unit / Valid Range

Valid range 0 ... 100 (default: 100 (no ﬁltering)). For information on setting the ﬁltering factor, see A.4.

Filtering Factor (page 88).

To apply an accurate relative humidity compensation (775), you must also enable temperature compensation (774) and pressure compensation (773).

A.2.3. Status Registers

Table 53 Modbus Status Registers (Read-Only)

Address (Decimal)

2049 08 00 Device status 16-bit 0 = Status OK.

Address (Hexadecimal)

Data Format

Notes

2 = Critical error, maintenance needed. 4 = Error, device may recover automatically. 8 = Warning.

2050 08 01 CO2 status 16-bit 0 = Status OK.

2 = CO2 reading not reliable. This status also appears during transmitter

start-up.

Multiple device statuses can be present simultaneously. In those cases, the value of the device status register is the sum of the applicable numbers, for example 12 if a warning (8) and an error (4) are present simultaneously.

A.2.4. Device Identiﬁcation Objects

Table 54 Device

Object ID (Decimal) Object ID

0 00 VendorName "Vaisala"

Identiﬁcation Objects

Object Name Example Contents

(Hexadecimal)

Appendix A – Modbus Reference

Object ID (Decimal) Object ID

Object Name Example Contents

(Hexadecimal)

1 01 ProductCode "GMP25x Carbon

Dioxide Probe "

2 02 MajorMinorVersion Software version (for

example "1.2.3")

3 03 VendorUrl "http://

www.vaisala.com/"

4 04 ProductName "GMP25X "

128 80

SerialNumber

Transmitter serial number (for example, "K0710040")

129 81

Calibration date

Date of the factory calibration

130 82

Calibration text

Information text of the factory calibration

1) Vaisala-speciﬁc device information object

GMP252 User Guide M211897EN-B

A.3. Modbus Communication Examples

Reading CO2 Value

Device address used in the following examples is 240 (F0h). The values returned by the device dier depending on the ambient conditions and/or device settings. Your device might not return exactly same values.

Request Response

Bytes on the Line (Hexadecimal)

(silence for 3.5 bytes) Start of Modbus RTU

F0 GMP25x address F0 GMP25x address

03 Function (Read Holding

00 Register address 04 Number of data bytes

00 D4 Value of ﬁrst register

00 Number of 16-bit

02 43 Value of second register

D1 Modbus RTU checksum E8

2A 33 Modbus RTU checksum

(silence for 3.5 bytes) End of Modbus RTU

Description Bytes on the Line

(Hexadecimal)

(silence for 3.5 bytes) Start of Modbus RTU

frame

03 Function (Read Holding

Registers)

registers to read (2)

frame

Description

frame

Registers)

(least signiﬁcant word)

(most signiﬁcant word)

(silence for 3.5 bytes) End of Modbus RTU

frame

Communication Description

(0-based format used in actual communication).

Data format Two 16-bit Modbus registers interpreted as IEEE 754

binary32 ﬂoating point value, least signiﬁcant word

ﬁrst.

Returned value 43E8D47Ah, which is binary32 representation of

465.65997 (ppm).

Writing Volatile Compensation Pressure Value

Request Response

Appendix A – Modbus Reference

Bytes on the Line (Hexadecimal)

(silence for 3.5 bytes) Start of Modbus RTU

F0 GMP25x address F0 GMP25x address

10 Function (Write

02 Register address 02 Register address

08 08

00 Number of registers to

02 02

04 Number of data bytes D4 Modbus RTU checksum

50 Value for the ﬁrst

00 (silence for 3.5 bytes) End of Modbus RTU

Description Bytes on the Line

(Hexadecimal)

(silence for 3.5 bytes) Start of Modbus RTU

frame

10 Function (Write

Multiple Registers)

00 Number of 16-bit

write (2)

93 register (least signiﬁcant word)

Description

frame

Multiple Registers)

registers written (2)

frame

44 Value for the second

0E Modbus RTU checksum

(silence for 3.5 bytes) End of Modbus RTU

signiﬁcant word)

frame

The response to a write function informs that the function was correctly received by the device. It does not guarantee that the written value was accepted by the device (for example, in case out-of-range values). To verify that the value was really accepted by the device, read the register value after writing.

Communication Description

0208h (0-based format used in actual communication).

GMP252 User Guide M211897EN-B

Communication Description

Data format Two 16-bit Modbus registers interpreted as IEEE 754

binary32 ﬂoating point value, least signiﬁcant word

ﬁrst.

Value to write 1013.25 (hPa), in binary32 format 447D5000h.

A.4. Filtering Factor

Modbus register 777 sets the CO2

ﬁltering factor. The ﬁltering factor aects the speed at which the latest CO2 measurement is integrated into the output of the probe. A new measurement is produced approximately every two seconds.

By default, the ﬁltering factory is set to 1.0, which means the latest measurement is shown directly in the output, without any ﬁltering. If the measuring environment produces occasional exceptionally high or low readings that need to be averaged out in the output, ﬁltering can be applied.

To apply

ﬁltering, you need to set a ﬁltering factor that determines how much the previous measurements aect the calculation of measurement output. For example, when using ﬁltering factor of 0.1, the new output is a combination of previous measurements (90%) and the latest measurement (10%).

Examples of the eect of ﬁltering on output:

• Filtering factor 1.0 = No ﬁltering, the latest measurement is output directly without integrating previous measurements.

• Filtering factor 0.5 = The reading output shows ~75% of the measurement change after two two-second measurement cycles and ~93% after four cycles.

• Filtering factor 0.1 = The reading output shows ~90% of the measurement change after 22 measurement cycles.

The

conﬁguration range of the ﬁltering factor is 0 ... 100 in the 16-bit register: for example, to

set the factor to 0.5, set the value of the register to 50.

The following formula is used when calculating the output:



o o m

new

old

new

= 

oldnew

New output Previous output New measurement

 

old

× 

f Filtering factor

Technical Support

Contact Vaisala technical support at helpdesk@vaisala.com. Provide at least the following supporting information:

• Product name, model, and serial number

• Name and location of the installation site

• Name and contact information of a technical person who can provide further information on the problem

For Vaisala Service Center contact information, see www.vaisala.com/servicecenters.

Warranty

For standard warranty terms and conditions, see www.vaisala.com/warranty.

Please observe that any such warranty may not be valid in case of damage due to normal wear and tear, exceptional operating conditions, negligent handling or installation, or unauthorized for details of the warranty for each product.

modiﬁcations. Please see the applicable supply contract or Conditions of Sale

Recycling

Recycle all applicable material.

Follow the statutory regulations for disposing of the product and packaging.

GMP252 User Guide M211897EN-B

www.vaisala.com

Vaisala GMP252 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

1. About This Document

1.1. Documentation Conventions

1.2. Version Information

1.3. Related Manuals

1.4. Trademarks

1.5. Patent Notice

2. Product Overview

2.1. Introduction to GMP252

2.2. Basic Features and Options

2.4. Environmental Compensation

2.4.1. Temperature Compensation

2.4.2. Pressure Compensation

2.4.3. Background Gas Compensation

2.5. Probe Startup

2.6. Analog Output Overrange Behavior

2.6.1. Analog Output Overrange Example

2.7. Safety

2.7.1. ESD Protection

2.8. Regulatory Compliances

3. Installation

3.1. GMP252 Probe Dimensions

3.2. Recommended Installation

3.3. Installation Accessories

3.3.1. 243261SP Installation Flange

3.3.2. 243257SP Mounting Clips

3.4. Power Supply

3.5. Wiring

4. Vaisala Industrial Protocol

4.1. Overview

4.2. Serial Interface Settings

4.3. Physical Interface

4.4. Connecting with a Computer

4.4.1. Installing the Driver for the USB Service Cable

4.5. Accessing Serial Commands from Modbus or Analog Mode

4.6. Enabling Modbus Mode from Vaisala Industrial Protocol

4.7. Changing From Digital Output to Analog Output

4.8. Serial Commands

4.9. Device Information and Status

4.10. Serial Line Output and Communication

4.11. Analog Output

4.12. Calibration and Adjustment

4.13. Environmental Compensation Commands

4.14. Other Commands

5. Modbus

6. Operating with MI70 Indicator

6.1. Overview of MI70 Support

6.2. Basic Display

6.3. Graphical Display

6.4. Main Menu

6.5. Connecting Probe to MI70 Indicator

6.6. MI70 Indicator Parts

6.7. Holding and Saving the Display

6.8. Recording Data

6.9. Changing Environmental Compensation Settings with MI70 Indicator

6.10.2. 1-Point Adjustment with a Reference Gas

7. Maintenance

7.1. Cleaning

7.1.1. Chemical Tolerance

7.2. Changing the Filter

7.3. Calibration and Adjustment

7.3.1. Calibration Setup

7.3.3. Limits of Adjustment

7.3.4. Adjustment Types

7.3.5. DRW244827SP Calibration Adapter

8. Troubleshooting

8.1. Problem Situations

8.2. Error Messages

8.3. Analog Output Error State

9. Technical Data

9.2. Spare Parts and Accessories

9.3. GMP252 Probe Dimensions

9.5. 243261SP Calibration Adapter Dimensions

Appendix A. Modbus Reference

A.1. Function Codes

A.2. Modbus Registers