Environmental compensation - GMP251

GMP251 User Guide

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User guide

When necessary, various environmental compensations can be applied to improve the CO2 measurement accuracy of the probe.

The probe can compensate for the effects of the following parameters:
  • Temperature
  • Pressure
  • Background gas oxygen (O2) content
  • Background gas relative humidity (%RH)
To apply an accurate relative humidity compensation, make sure that also the temperature compensation and pressure compensation configurations match the measurement environment.

The probe has an on-board temperature sensor that can be used to compensate for temperature. Additionally, if the probe is integrated in a system that measures one or more of the compensation parameters (T, P, RH, O2), they can be updated to the probe continuously.

Compensation parameters are configured on the order form when ordering the probe, and can later be updated using Vaisala Industrial Protocol or Modbus protocol.

You can also turn off any of the compensations. In that case, the probe uses the default compensation value that is mathematically neutral for the probe’s internal compensation model.

You can configure the environmental compensation settings with any of the following options:
  • Vaisala Industrial Protocol serial commands
  • Vaisala Insight software
  • Modbus configuration registers
  • MI70 handheld indicator
  • Indigo80 handheld indicator
The environmental compensation configuration options available in the MI70 handheld indicator are not compatible with the probe. Using MI70 to configure the environmental compensation settings of the probe can decrease measurement accuracy.