Danfoss calibrates Thermostats and Pressostats using Motors and Controllers from JVL

 

The well-known Danfoss KP thermostats and pressostats are calibrated in a set-up that includes the use of 2 step motors and associated SMD15B Drivers from JVL. The set-up is controlled by a Hitachi PLC.

Each Thermostat/Pressostat has 3 adjustment screws: a "stop screw" that determines mechanical displacement, an adjustment screw for adjusting the unit's control range in Bar or degrees Centigrade, and a screw for adjusting differential pressure or temperature. The stop-screw is adjusted by a photocell, while the latter two controls are set relative to reference values using the two step motors.
Adjustment of the unit's control range and differential pressure range is accomplished by comparing the signal from a pressure transducer with the required values. The step motor pulses are generated by the PLC, which calculates the required number of steps on the basis of the measurements taken.

The final adjustment of the pressostats/thermostats adjusts the units according to the actual pressure/temperature the sensor experiences. These adjustments are also done using step motors.

Danfoss has recently converted a large number of manual workplaces to incorporate these automated processes.

 

This is being done in a continuing effort to avoid work that involves very repetitive tasks. Many of the new calibration stations have been established at Danfoss' new factory near Warsaw in Poland.

 

 

 

Workplace for calibration of pressostats/thermostats.