Siemens AVS75.39 Series User Manual page 106

Minimum limitation of
the return temperature
Return setpoint min
Return setpoint min
OEM
Return influence
consumers
Return circuit mixing
valve
Actuator: running time
Mixing valve Xp
Mixing valve Tn
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Siemens
Building Technologies
Line no. Operating line
3560 Return setpoint min
3561 Return setpoint min OEM
3562 Return influence consumers
If the return temperature falls below the return temperature setpoint, maintained
boiler return temperature becomes active.
The maintain return permits influences on consumers of the use of a return
controller.
The adjustable return temperature minimum limitation (BZ3560) can be lowered on
the OEM side.
The user at the heating technician level can no longer enter the cascade return
temperature minimum limitation below the minimum value required by the boiler.
If, with the boiler released, the cascade return temperature falls below the set
minimum temperature, a locking signal will be calculated.
With proper pump circuits (heating circuit pump, DHW charging pump, external
load), the consumer pumps will be deactivated, or will stay deactivated, if the
locking signal exceeds the relevant threshold value
With mixing heating circuits, the flow temperature setpoint will be lowered in
accordance with the value of the locking signal
Line no. Operating line
3570 Actuator running time
3571 Mixing valve Xp
3572 Mixing valve Tn
Setting the running time for the actuator used with the mixing valve.
By setting the right proportional band Xp for the mixing valves actuator, the control
behavior of the actuator is matched to those of the plant (controlled system).
The proportional band Xp influences the controller's P-action.
The P band Xp is the range by which the input variable x (controlled variable) must
change to adjust the output variable y (manipulated variable) throughout the entire
positioning range. The smaller the value the greater the jump. The illustration
depicts the reciprocal value 1/Xp = Kp.
By setting the right integral action time Tn, the control action of the mixing valve's
actuator is matched to the behavior of the plant (controlled system).
Tn influences the controller's I-response.
It is the required of the I-portion to undertake the same manipulated variable
change at the given input signal (controlled variable), as immediately provided by
the P-portion. The smaller the Tn the larger/faster the slope.
User manual RVS43.345
The settings in detail
CE1U2354en_021
2013-09-02