Problem situations - GMP231

GMP231 User Guide

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Table 1. Possible problem situations and their remedies
Problem Possible cause Remedy
Analog output reading is unchanging and appears incorrect. Analog output is in error state. Remove the cause of the error state and the analog output recovers its normal function.
Probe outputs stars "****" on serial line instead of measurement data. Incorrect supply voltage. Check the power supply. Check the active errors using the ERRS command on the serial line.
Unsuitable operating environment. Verify that the operating environment is within specified operating limits.
Unable to access probe on RS-485 line. Incorrect wiring. Check that the RS-485 connection is wired correctly.
Power cycle or reset the probe and try again.
Probe in POLL mode with unknown address. Issue the ?? command to make the probe output its information. Then use the OPEN command to open a line to the probe’s address.
CO2 measurement not working. Condensation on the sensor. Remove the PTFE filter and check if condensation has formed on the sensor. If yes, dry out the condensation with instrument air and insert a new dry filter. Keep the probe powered and operating to prevent re-occurrence.