Analog output overrange behavior - GMW83 - GMW83A - GMW83D - GMW83DRP - GMW83DRPC - GMW83RPC - GMW84 - GMW84S - GMW86P

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.

Figure 1. Overrange behavior at 0 … 2000 ppm CO₂ measurement range with 4 ... 20 mA output

Figure 2. Overrange behavior at 0 … 5000 ppm CO₂ measurement range with 4 ... 20 mA output

Negative ppm values cannot physically exist but the behavior of the output is defined to account for cases where a low CO₂ reading, combined with sensor drift, could cause a negative result.

Figure 3. Overrange behavior at 0 … 2000 ppm CO₂ measurement range with 0 ... 10 V output

Figure 4. Overrange behavior at 0 … 5000 ppm CO₂ measurement range with 0 ... 10 V output

Figure 5. Overrange behavior of active temperature measurement

Passive temperature measurement (reading the Pt1000 resistor) is not affected by the overrange behavior or the error state.

Figure 6. Overrange behavior of relative humidity measurement

The transmitter can measure humidities in excess of 100 %RH if the sensor element becomes wet due to condensation.

Analog output overrange behavior - GMW83 - GMW83A - GMW83D - GMW83DRP - GMW83DRPC - GMW83RPC - GMW84 - GMW84S - GMW86P - GMW87M

GMW80 Series User Guide