Quick Reference Guide
Vaisala CARBOCAP
®
Carbon
Dioxide Module GMM112 and
Transmitter GMW115
– GMM112 compact diffusion
aspirated CO
2
module for OEM
applications
– GMW115
CO
2
transmitter for wall
mounting
– Measurement range 0 ... 2000 ppm or
0 ... 5000 ppm CO
2
– Ideal for HVAC applications
ELECTRICAL CONNECTIONS
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
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
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).
0601-001
Figure 1 Connection of Separate AC Supplies (Recommended)
0601-002
Figure 2 Connection of Single AC supply to Several Transmitters
MOUNTING AND DIMENSIONS
Dimensions
mA
V
0
B
A
0
24V
mA
V
0
B
A
0
24V
25
65
6
30
60
96
Ø3.2
0601-004
Figure 3 GMM112 Module Connections and Dimensions
66.3
60
60
Ø 4.
2
66.7
85.
3
83.4
85.2
R2.1
124
120.9
25.8
84
R3
.5
0601-005
Figure 4 GMW115 Transmitter Dimensions
