User Manual

2
Siemens CB1Q3950en
Smart Infrastructure 2020-06-08
Technology
Electronic expansion valve
Electronic expansion valves control the refrigerant mass flow in evaporators for chiller, air-
conditioner and refrigerator applications. In addition, modulating valves can be used for
several control functions such as liquid injection, hot gas bypass and evaporator pressure
regulation.
The POL94X.00/xxx extension module is designed as a driver for electronic expansion
valves, features a channel drive for a wide range of bipolar stepper motors. With the main
controller, POL94X.00/xxx module controls refrigerant superheat and optimizes the efficiency
of the refrigerant circuit, to enhance the maximum capacity for chillers, air-conditioners and
refrigerators.
Bipolar stepper motors
Bipolar permanent magnet and hybrid motors have two windings. The drive circuitry for such
a motor requires an H-bridge control circuit for each winding. Briefly, an H-bridge allows the
polarity of the power applied to each end of each winding to be controlled independently.
Installation concept
Communication concept