HDH-C and HDK-C are designed to provide control functionality for the HDH room CO2 and HDK duct CO2 transmitters.

In normal operating conditions the HDH and HDK do not require calibration due to ingenious auto-calibration routines. However if the units are installed to environments that have significantly different base CO2 levels, then HDH/HDK/-C calibration tool can be used for resetting the base CO2 levels.

HDH-C can also be used to set the Modbus addresses for the HDH-M Modbus RTU RS-485 CO2 transmitters. The HDH-C allows adjustment of the Modbus addresses and baud rate.