Multi-Zone Control - Siemens SINAMICS G120 CU230P-2 HVAC Operating Instructions Manual

7.9.11

Multi-zone control

Multi-zone control is used to control quantities such as pressure or temperature via the
technology setpoint deviation. The setpoints and actual values are fed in via the analog
inputs as current (0 ... 20 mA) or voltage (0 ... 10 V) or as a percentage via temperature-
dependent resistances (NI1000 / PT1000, 0 °C = 0 %; 100 °C = 100 %).
Control variants for multi-zone control
There are three control variants for multi-zone control, which are selected via p31021:
● One setpoint and one, two or three actual values
● Two setpoint/actual value pairs as maximum value control (cooling)
● Two setpoint/actual value pairs as minimum value control (heating)
Frequency inverters with Control Units CU230P-2 HVAC, CU230P-2 DP, CU230P-2 CAN
Operating Instructions, 01/2011, FW 4.4, A5E02430659B AD
The actual value for the control can be calculated as mean value, maximum value or
minimum value. You can find all of the setting options in the parameter list in parameter
p31022.
– Average value: The deviation from the setpoint of the average value of two or three
actual values is controlled.
– Minimum value: The deviation from the setpoint of the smallest actual value is
controlled.
– Maximum value: The deviation from the setpoint of the highest actual value is
controlled.
The maximum value control compares two setpoints/actual value pairs and controls the
actual value which has the largest deviation upwards from its associated setpoint. No
control takes place if both actual values lie below their setpoints.
In order to avoid frequent changeover, the inverter only switches over if the deviation of
the controlled setpoint-actual value pair is more than two percent lower than the deviation
of the uncontrolled value pair.
The minimum value control compares two setpoints/actual value pairs and controls the
actual value, which has the highest deviation downwards from its associated setpoint. No
control takes place if both actual values lie above their setpoints.
In order to avoid frequent changeover, the inverter only switches over if the deviation of
the controlled setpoint-actual value pair is more than two percent lower than the deviation
of the uncontrolled value pair.
7.9 Application-specific functions
Functions
257