Status word - GMP231

GMP231 User Guide

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User guide

The status word is used to monitor the status of the GMP231 device. It can be read in the same way as any other slave parameter. The status word is used as a 32-bit long bit field, where each bit represents a state of some error or other essential status. The status word is sent least significant bit (LSB) first.

The status word content is updated every two seconds. Changes in the status word bits can be monitored by reading the status byte.

Table 1 lists the content of the status word. The status bits are categorized according to the severity of the status:

  • Critical errors are fatal to the operation of the unit. It may not be able to respond to communication at all, and does not measure correctly.
  • Errors prevent CO2 measurement and cause the analog outputs to be set to the error state. Depending on the problem, errors may resolve themselves. For example, sensor heating eventually dries out condensation on the optical surfaces.
  • Warnings do not prevent normal operation but may indicate possible problems.
  • Status indicates a known state of the unit, such as the CO2 measurement standby mode.

There are several possible internal error statuses that you cannot do much about. After using the instructions in the following table and in Problem situations, try to power cycle the probe and see if the error stays on.

If your unit has persistent errors that you cannot resolve yourself, contact Vaisala.

Table 1. Status word content
Bit# Type Meaning Recommended action
0 Critical Error Program memory corrupted (CRC error). Fatal error, contact Vaisala.
1 Critical Error Parameter memory corrupted (CRC error). Fatal error, contact Vaisala.
2 Reserved
3 Reserved
4 Error Low supply voltage error. Check supply voltage.
5 Error Low internal 30 V voltage.
6 Error Low input signal. Can be caused by dirt or condensation on the optical surfaces.

Wait to see if condensation is removed by heat.

For cleaning instructions, see Cleaning.

7 Error Low internal 8 V voltage.
8 Error Signal dynamic range too high.
9 Error Pressure sensor communication.
10 Error Pressure sensor out of range.
11 Error Sensor temperature too high for operation. Wait for sensor to cool down.
12 Error CO2 concentration too high to measure. Wait for CO2 concentration to fall into the measurable range.
13 Error Sensor heater resistance out of range.
14 Error IR source temperature error too high.
15 Reserved
16 Error Internal 2.5 V voltage out of range.
17 Error Internal 1.7 V voltage out of range.
18 Error Low IR current.
19 Reserved
20 Warning Low input signal. Can be caused by dirt or condensation on the optical surfaces. Continue normally.
21 Reserved
22 Warning Noisy signal. Continue normally.
23 Warning Transmitter reset by watchdog process. Continue normally.
24 Status CO2 measurement in standby mode: set automatically due to high temperature. Wait for sensor to cool down.
25 Status CO2 measurement in standby mode: set by user command. Set to normal mode when desired.
26 Status CO2 adjustment state on. Complete the CO2 adjustment.
27 Reserved
28 Reserved
29 Reserved
30 Reserved
31 Reserved