Vaisala GMP251 User manual

M211920EN-C
Quick Guide
GMP251 and GMP252
Relay Box for GMP250 Carbon Dioxide Probes

PUBLISHED BY
Vaisala Oyj
Vanha Nurmijärventie 21, FI-01670 Vantaa, Finland
P.O. Box 26, FI-00421 Helsinki, Finland
[phone]
Visit our Internet pages at www.vaisala.com.
© Vaisala Oyj 2018
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. Relay Box Quick Guide
1.1 Overview
The GMP250 relay box allows using the analog current (mA) output channel of Vaisala
CARBOCAPâCarbon Dioxide Probes GMP251 and GMP252 for relay control.
The voltage (V) output channel is not used for relay control with the relay box: the voltage
channel provides CO2measurement output (feedthrough via the relay box) in the same
manner as when wired directly without the relay box.
The relay configuration (activation and release limits, error state output) is done using
GMP251/252 serial line interface commands.
Table 1 GMP250 Relay Box Specifications
Property Specification
Maximum switching voltage 50 VDC, 50 VAC
Maximum switching power 30 W, 30 VA
Number of relays 1
Probe output to relay • Current output to relay control: ppm CO2
• Voltage output through the relay box: ppm CO2or
% CO2
Probe power supply requirements 20 ... 30 VDC supplied through the relay box
Relay configuration interface Serial line (Vaisala Industrial Protocol)
Using GMP251/252 for relay control requires using the Vaisala Industrial Protocol serial line
interface to configure the probe to use relays, and wiring the probe to send output and
receive power through the relay box.
• For instructions on carrying out the serial line configuration, see Serial Line
Configuration (page 4).
• For wiring instructions, see Probe and Relay Box Wiring (page 10) .
This Quick Guide instructs how to carry out the serial line configuration and wiring related
to using the current output for relay control. For more information on GMP251/252 serial
line commands and other functionalities, see the user documentation of the probes:
•GMP251 User Guide (M211799EN)
•GMP252 User Guide (M211897EN)
Chapter 1 – Relay Box Quick Guide
3

1.2 Serial Line Configuration
To enable relay operation, you must use a terminal program (for example, PuTTy) to set the
GMP251/252 serial mode to relay communication and configure the relay settings. Using
serial line (Vaisala Industrial Protocol) to configure the probe requires the following:
• 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 default serial interface settings are shown in the following table.
Table 2 Default Serial Interface Settings
Property Description/Value
Bit rate 19200
Parity None
Data bits 8
Stop bit 1
Flow control None
For more detailed instructions on connecting to GMP251/GMP252 with a computer and
using the serial line interface, see the User Guides of the probes.
1.3 Configuring Relays with Serial Line
To enable relay control with the current output channel and set the relay configuration,
follow the instructions below for the relevant software version.
More Information
‣Configuring Relays with GMP250 Software Version 1.3.1 or Later (page 5)
‣Configuring Relays with GMP250 Software Version 1.2.9 (page 7)
Relay Box for GMP250 Carbon Dioxide Probes Quick Guide M211920EN-C
4

1.3.1 Configuring Relays with GMP250 Software Version 1.3.1 or
Later
Use the rsel command (not the asel command) to set the analog output channel to
current (mA).
1. Connect GMP251/GMP252 to a computer with USB service cable 242659 and open a
terminal connection (for example, PuTTy).
2. Enable advanced configuration commands with the pass 1300 command.
3. Set the serial mode of the analog current output channel (2) to relay control with the
following command: smode relay2
Chapter 1 – Relay Box Quick Guide
5

4. Configure the current output channel's relay settings with the rsel command:
rsel [channel parameter release_ppm set_ppm release_value set_value
startup_value error_value]
•channel= analog output channel: set to 2(current)
•parameter = the parameter that controls the relay: set to co2
•release_ppm = CO2ppm level at which the relay is released
•set_ppm = CO2ppm level at which the relay is activated
•release_value = the current output (mA) when the relay is released
•set_value = the current output (mA) when the relay is activated: set to 12
•startup_value = during probe start-up, if the CO2ppm level falls between the
release_ppm and set_ppm values, startup_value shows the state of the relay
(mA): the relay is either activated, released, or in error state.
•error_value = the current output when the probe is in error state
The relay mode of GMP251 and GMP252 probes has been designed to use 12 mA as
the relay control current. Use only 12 mA for the set_value configuration when
using the relay box with GMP251 and GMP252.
Example:
Set the analog output channel 2 (current) to control relay operation with the following
settings:
• The relay is activated when the measurement is over 10100 ppm CO2and released
when under 9900 ppm CO2. Setting these relay activation limits means using a
1 % CO2(10 000 ppm CO2) relay setpoint with a hysteresis of ±1 % (100 ppm CO2).
• The output current is 0 mA when the relay is released.
• The output current is 12 mA when the relay is activated.
• The output current is 12 mA if during probe start-up CO2ppm level is between 9900
and 10100 ppm.
• The output current is 0 mA when the probe is in error state.
Enter the following commands:
pass 1300
smode relay2
rsel 2 co2 9900 10100 0 12 12 0
Relay Box for GMP250 Carbon Dioxide Probes Quick Guide M211920EN-C
6

1.3.2 Configuring Relays with GMP250 Software Version 1.2.9
Use the rsel command (not the asel command) to set the analog output channel to
current (mA).
1. Connect GMP251/GMP252 to a computer with USB service cable 242659 and open a
terminal connection (for example, PuTTy).
2. Enable advanced configuration commands with the pass 1300 command.
3. Set the serial mode of the analog current output channel (2) to relay control with the
following command: smode relay2
4. Configure the current output channel's relay settings with the rsel command:
rsel [channel parameter release_ppm set_ppm set_value error_value]
•channel= analog output channel: set to 2(current)
•parameter = the parameter that controls the relay: set to co2
•release_ppm = CO2ppm level at which the relay is released
•set_ppm = CO2ppm level at which the relay is activated
•set_value = the current output (mA) when the relay is activated: set to 12
•error_value = the current output when the probe is in error state
The relay mode of GMP251 and GMP252 probes has been designed to use 12 mA as
the relay control current. Use only 12 mA for the set_value configuration when
using the relay box with GMP251 and GMP252.
Example:
Set the analog output channel 2 (current) to control relay operation with the following
settings:
• The relay is activated when the measurement is over 10100 ppm CO2and released
when under 9900 ppm CO2. Setting these relay activation limits means using a
1 % CO2(10 000 ppm CO2) relay setpoint with a hysteresis of ±1 % (100 ppm CO2).
• The output current is 12 mA when the relay is activated.
• The output current is 0 mA when the probe is in error state.
Enter the following commands:
pass 1300
smode relay2
rsel 2 co2 9900 10100 12 0
Chapter 1 – Relay Box Quick Guide
7

1.3.3 Serial Line Mode Commands
Only serial mode commands related to relay operation are presented here. For other serial
mode configuration options, see the User Guides of the GMP251/252 probes.
Table 3 Smode Command
Syntax Description
smode<cr> Shows the current start-up operating mode of the
serial line.
smode [mode]<cr> Set serial line start-up operating mode. The new mode
is taken into use when the device is reset or powered
up. Note: only use the RELAY2 option.
Available modes:
RELAY1 = Voltage output channel: do not use for relay
control with the GMP250 relay box.
RELAY2 = Set analog output channel 2 (current) to
relay control: use only this option with the relay box.
Example (set serial mode to "RELAY2" (channel 2 current output)):
smode RELAY2
Serial mode : RELAY2
1.3.4 Relay Configuration Commands
Table 4 Rsel Command for GMP250 Software Version 1.3.1 or Later
Syntax Description
rsel [channel]<cr> Show current relay settings.
channel = Analog output channel
Relay Box for GMP250 Carbon Dioxide Probes Quick Guide M211920EN-C
8

Syntax Description
rsel [channel parameter release_ppm
set_ppm release_value set_value
startup_value error_value]<cr>
Configure relay operation of the channel.
channel = Analog output channel
• 1 = voltage output (V): not used with relay
•2= current output (mA): only use this option with
the relay box.
parameter = The parameter that is output on analog
channel. The only option is CO2 (in ppm).
release_ppm = CO2level at which the relay is
released.
set_ppm = CO2level at which the relay is activated.
release_value = The current output (mA) when
the relay is released.
set_value = Current (mA) output when the relay is
activated. Set to 12 when using the relay box with
GMP251/252.
startup_value = During probe start-up, if the CO2
ppm level falls between the release_ppm and
set_ppm values, startup_value shows the state
of the relay (mA): the relay is either activated,
released, or in error state.
error_value = The current (mA) that is output
when the probe is in an error state.
Table 5 Rsel Command for GMP250 Software Version 1.2.9
Syntax Description
rsel [channel]<cr> Show current relay settings.
channel = Analog output channel
rsel [channel parameter release_ppm
set_ppm set_value error_value]<cr>
Configure relay operation of the channel.
channel = Analog output channel
• 1 = voltage output (V): not used with relay
•2= current output (mA): only use this option with
the relay box.
parameter = The parameter that is output on analog
channel. The only option is CO2 (in ppm).
release_ppm = CO2level at which the relay is
released.
set_ppm = CO2level at which the relay is activated.
set_value = Current (mA) output when the relay is
activated. Set to 12 when using the relay box with
GMP251/252.
error_value = The current (mA) that is output
when the probe is in an error state.
Chapter 1 – Relay Box Quick Guide
9

The relay mode of GMP251 and GMP252 probes has been designed to use 12 mA as the
relay control current. Use only 12 mA for the set_value configuration when using the
relay box with GMP251 and GMP252.
1.4 Probe and Relay Box Wiring
Function Wire Color
Output control
Voltage output
Current output
GND
Power in
Gray
White
Black
Blue
Brown
GMP25X Probe
Voltage
NC
NC
Current
GND
Power Power
GND
Vout
GND
Relay
Relay
Inputs / Outputs
Relay Box Input/Output
GND
Power supply to GMP25x
Voltage output from GMP25x *
GND
Relay contact
Relay contact
Power supply to GMP25x:
20 ... 30 VDC (for current output)
*) Voltage output from GMP25x is internally connected to Vout
Figure 1 Probe and Relay Box Wiring
1. Open the relay box screws and remove the cover.
2. Lead the GMP251/252 probe connection cable with open wires (223263SP/244669SP/
216546SP) through the left cable gland and connect the open wires to the screw
terminals as shown in Figure 1 (page 10).
3. Lead the relay box input/output cable through the right cable gland and connect the
wiring as shown in Figure 1 (page 10).
Do not switch on the power supply before you have completed the
wiring and reattached the relay box cover.
CAUTION!
4. After the wiring is complete, reattach the relay box cover and switch on the 20 ... 30
VDC power supply.
Relay Box for GMP250 Carbon Dioxide Probes Quick Guide M211920EN-C
10