Transmitter model GMW83A has indicator LEDs for the measured CO
2
level on the front cover.
The LEDs provide a visual indication of the measured CO
2
level to the occupant of the
monitored space.
The LEDs are lit as follows:
• Red LED (top): lit between 1200 ... 2000 ppm CO
2
, blinking > 2000 ppm CO
2
.
• Yellow LED (center): lit between 800 ... 1200 ppm CO
2
.
• Green LED (bottom): lit between 0 ... 800 ppm CO
2
.
2.5 Analog output overrange behavior
Analog outputs of the GMW80 series transmitters have a defined behavior when the values
measured by the transmitter are outside the scaled analog output range.
• At the top end of the output range, the output is clipped to the maximum value of the
output. This means that even if the measured parameter rises, the value does not change
anymore.
• At the low end of the output range, the output stays at the minimum value when the
measured parameter falls below the scaled range.
• The output is eventually set to the error state if the measured parameter is far enough
from the scaled output range. The exact limits for this behavior are parameter dependent;
see the figures below.
For more information on the error state, see
.
20.0
0
0
2000
6000
Output clipping limit
Error level
CO
2
(ppm)
-100
Output
(mA)
Scaled output range:
4 ... 20 mA
0 ... 2000 ppm
3.6
4.0
Figure 11 Overrange behavior of CO
2
measurement with 4 ... 20 mA output
Chapter 2 – Product overview
17
