The S9xx range can be connected to a PLC or current sensing device via the 4-20mA output to provide concentration information. The output is linearly proportional to concentration. The full scale (20mA) value is factory set but can also be user configured with the Configuration PC software. If the sensor
fails the output will be 20mA. It is recommended that the DIAG output is used to monitor for faults.
The 4-20mA output loop is opto-isolated from the instrument and it is recommended that it be powered by a separate power supply with a voltage in the range 12-24V applied with the correct
polarity. This will produce the most reliable connection method. If opto-isolation is not important then the 4-20 mA loop may be powered by the same power supply as the unit.
- Connect the 4-20mA loop on the screw connector to the power supply and current measuring device (e.g. PLC) ensuring the polarity is correct. Please refer to the diagrams below.
Note: If the polarity is incorrect the 4-20mA output may be permanently Damaged.
- Power on the instrument and PLC
- Check the PLC or current sensing device to ensure data is being shown