GMP231 provides several outputs you can use. Connect the output pins you need, and the power supply and ground pins. Use a shielded cable, and connect the shield to the chassis of the GMP231’s M12 connector, and to ground on the other side.
Ground pin 5 to put the probe in standby mode (stops CO2 measurement). The probe resumes normal measurement operation when pin 5 is no longer grounded, unless its internal measurement shows the temperature is too high.
| Male 8-pin M12 | Pin # | Function |
|---|---|---|
 |
1 | I2C SDA |
| 2 | RS-485 D- | |
| 3 | I2C SCL | |
| 4 | Analog output + | |
| 5 | Standby | |
| 6 | RS-485 D+ | |
| 7 | Power supply + | |
| 8 | Ground | |
| - | Shield |
Vaisala’s standard connection cable for the GMP231 (item code DRW240977) is a 90 cm long cable with female 8-pin M12 connector on one end, and open ended wires on the other. It supports all outputs from the GMP231, and connects the cable shield to the connector chassis.
| Female 8-pin M12 | Pin # | Function | Wire color |
|---|---|---|---|
 |
1 | I2C SDA | White |
| 2 | RS-485 D- | Brown | |
| 3 | I2C SCL | Green | |
| 4 | Analog output + | Yellow | |
| 5 | Standby | Gray | |
| 6 | RS-485 D+ | Pink | |
| 7 | Power supply + | Blue | |
| 8 | Ground | Red | |
| - | Shield | Black |