Vaisala CARBOCAP GMM112, CARBOCAP GMM115 Quick Reference Manual

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

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 [e-mail]

Repair and calibration services are provided by Vaisala Service Centers:

, or by fax [phone].

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