Adjust - GMP231

GMP231 User Guide

Document code
M211501EN
Revision
E
Language
English (United States)
Product
GMP231
Document type
User guide

Adjust command (ID 84hex) controls the user adjustment sequence of CO2 measurement.

Table 1. Adjust invoke message
Message segment Length Content
I2C address 1 byte I2C address (write)
Command ID 1 byte Always 84hex
Device address 1 byte See Table 2.
Frame length 1 byte Varies according to data length, 07hex ... 0Bhex.
Data 1 byte Adjustment subcommand. See Table 3.
1 byte Parameter to be adjusted. See Table 4.
4 bytes Value of parameter. Used only with subcommands 2 and 3.
Checksum 2 bytes See Checksum.
Table 2. Adjust response message
Message Segment Length Content
I2C address 1 byte I2C address (read)
Status 1 byte See Status byte.
Command ID 1 byte Always 84hex
Device address 1 byte See Table 2.
Frame length 1 byte Always 07hex.
Data 1 byte Return code. See Table 5.
Checksum 2 bytes See Checksum.
Table 3. Adjustment subcommands
Code Adjustment operation
0 Start 1 point adjustment
1 Start 2 point adjustment
2 Record measured point 1, reference value is given in parameter
3 Record measured point 2, reference value is given in parameter
4 Cancel adjustment (previous adjustment is reverted)
5 End (adjustment is saved and new values are taken in use)
6 Revert to factory calibration (clear user adjustment)
Table 4. Adjustment parameters
Code Purpose
0 All parameters (valid with revert to factory calibration)
1 CO2
Table 5. Adjustment return codes
Code Meaning
0 OK
1 Function not supported
2 Sequence error
3 Recorded-Reference difference too large
4 2-point adjustment: Points too close
5 Given reference value is invalid