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ELECTRICAL CONNECTIONS
MOUNTING AND DIMENSIONS
Quick Reference Guide
Vaisala CARBOCAP® Carbon
Dioxide Module GMM112 and
Transmitter GMW115
– GMM112 compact diffusion
aspirated CO
applications
module for OEM
2
mA Signal 4 ... 20 mA
V Signal (+) 0 ... 10 V
0 Signal (-)
B RS-485 Signal B
A RS-485 Signal A
0 Power supply (-)
24V Power supply (+) 24 VDC/VAC
Dimensions
mA
mA
V
Ø3.2
V
0
0
B
B
A
A
0
0
24V
24V
96
25656
See Figure 3 for wire terminals.
Powering
The products require a nominal 24 VDC/VAC power supply
maintaining a voltage of 18 ... 30 VDC or 20 ... 26 VAC for all
load conditions and all mains voltages. Although the power input
includes a half-wave rectifier, it is recommended to use a DC
supply to avoid current peaks.
Connections to 24 VAC Power Supply
Connecting more than one transmitter to a single 24VAC
transformer forms a common loop and increases the risk of a
Figure 3 GMM112 Module Connections and Dimensions
30
60
0601-004
66.3
60
short-circuit. Therefore, a separate floating supply for each
transmitter is recommended (see Figure 1).
If several transmitters share a common transformer, the phase (~)
must always be connected to the 24 V connector in each
transmitter (see Figure 2).
85.2
83.4
85.
3
1
.
2
R
2
4.
Ø
60
66.7
124
120.9
– GMW115 CO
transmitter for wall
2
mounting
– Measurement range 0 ... 2000 ppm or
0 ... 5000 ppm CO
2
– Ideal for HVAC applications
0601-001
25.8
Figure 1 Connection of Separate AC Supplies (Recommended)
Figure 4 GMW115 Transmitter Dimensions
0601-002
Figure 2 Connection of Single AC supply to Several Transmitters
R3
.
5
84
0601-005
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Mounting the GMW115 Transmitter
Mount the back plate onto a wall using screws. Make sure the
back plate is mounted in with the same orientation as in Figure 4.
GMW115 Cover Opening/Closing
0601-006
Figure 5 Opening the GMW115 Cover
0601-007
Figure 6 Closing the GMW115 Cover
SERIAL COMMUNICATION INTERFACES
The modules support RS232 or RS485 communication. RS232 is set as
factory default. The RS485 interface is selected by serial command. The
communication settings for both interfaces are: 9600, N, 8, 1.
RS485 Interface
The interface is non-isolated two-wire interface with no internal bus
termination. If termination is needed, use RC termination (100 Ω resistor
in series with 1 nF capacitor) at both ends of the bus. See serial
commands list below to activate the RS485 interface.
RS232 Interface
Use the RS-232 interface for setting the operating parameters. The
connection cable between PC and module (a serial COM adapter for
maintenance purposes) is available from Vaisala (order code:
19040GM).
www.vaisala.com Ref. M210746EN-D
SERIAL COMMANDS
Serial commands are the same for RS232 and RS485 interface.
<cr> stands for pressing ENTER.
Polling command for CO
SEND <cr>
Setting the interval for the RUN (continuous output) mode:
INTV X Y<cr>
X = 0 (default) ... 255
Y = S/MIN/H
Starting the continuous mode printing:
R<cr>
Stopping the continuous mode printing:
S<cr>
Saving the parameters into the memory:
SAVE<cr>
Enabling/disabling the RS485 interface:
RS485 X<cr>
X = ON/OFF
Changing the operation mode:
SMODE X<cr>
X = STOP (default) / RUN / POLL
Giving the device address:
ADDR X<cr>
X = 0 (default) ... 99
Opening the polling line:
measurement (ppm):
2
TECHNICAL DATA
Property Description / Value
Performance
Measurement ranges 0 ... 2000 ppm CO
Measurement accuracy
(incl. repeatability, nonlinearity and calibration
uncertainty)
Long-term stability ± 5 % of range / 5 years
Response time 1 min
Temperature dependence of
reading
Pressure dependence of
reading
Warm-up time 1 min
10 min full specification
Product lifetime > 10 years
Operating environment
Operating temperature
range
Operating humidity range 0 ... 85 %RH
Operating pressure range 700 hPa ... 1200 hPa
Inputs and outputs
Operating voltage 24 V (±20 %) AC/DC
Power consumption < 2 W
Connections Screw terminals, wire size
OPEN addr<cr>
addr = 0 (default) ... 99
Closing the polling line:
CLOSE<cr>
Outputs
analog 0 ... 10 V, 4 ... 20 mA
serial RS-485, 2-wire, non-isolated
Recommended external
SERVICE, CALIBRATION AND ADJUSTMENT
These products are designed to operate their lifetime without
maintenance The transmitters are calibrated before shipping from the
factory. For technical questions, contact the Vaisala technical support; by
e-mail helpdesk@vaisala.com
Repair and calibration services are provided by Vaisala Service Centers:
, or by fax +358 9 8949 2790.
load
current output < 500 Ω
voltage output > 1 kΩ
Electromagnetic
compatibility
Materials
Weight GMM112: 34 g
GMW115: 105 g
GUARANTEE
Vaisala issues a guarantee for the material and workmanship
of this product under normal operating conditions for one (1)
year from the date of delivery. Exceptional operating
conditions, damage due to careless handling and
misapplication will void the guarantee.
0 ... 5000 ppm CO2
2
±(2.5 % of range + 3 % of
reading)
-0.35 % of reading / °C
(typical)
+ 0.15 % of reading / hPa
(typical)
-5 … +45°C
2
0.5 ... 1.5 mm
EN61326-1:
Generic Environment
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