Siemens AVS75.39 Series User Manual page 122

Pump overrun time
Overtemperature
protection
Excess heat discharge
Maintained boiler
return temperature
Return setpoint min
Return setpoint min OEM
Flow influence return
temp control
Actuator: Running time
Parameters Xp and Tn
Mixing valve Xp
Mixing valve Tn
122 / 239
Siemens
Building Technologies
Line no. Operating line
4140 Pump overrun time
If the temperature of the solid fuel boiler drops below the minimum temperature
differential or the minimum setpoint, the boiler pump keeps running for the
parameterized overrun time.
Line no. Operating line
4141 Excess heat discharge
If the boiler temperature reaches the adjusted maximum value, excess heat
discharge becomes active. This forces the connected consumers to draw heat from
the boiler. At the same time, the boiler pump is switched on.
Line no. Operating line
4153 Return setpoint min
4154 Return setpoint min OEM
4158 Flow influence return ctrl
Off ¦ On
4163 Actuator running time
4164 Mixing valve Xp
4165 Mixing valve Tn
The controller prevents the return temperature from falling below the level set here
by adding hot flow water.
The adjustable return temperature minimum limitation (line 4153) for the solid fuel
boiler 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 solid fuel
boiler.
The return temperature controller can also be used to achieve the flow setpoint if
wanted. Influence of the flow on the control of the return temperature can be
switched on or off.
Return sensor B72 must be connected for functions line 4153 and 4158.
Setting the running time for the actuator used with the mixing valve.
By setting the right proportional band Xp and integral action time Tn, the control
action can be matched to the type of plant (controlled system).
The proportional band Xp influences the controller's P-action.
Xp is the range by which the input signal (control variable) needs to change for the
output signal (manipulated variable) to be adjusted across the whole correcting
span.
The smaller Xp, the greater the change of the manipulated variable.
The integral action time Tn influences the controller's I-action.
Tn is the time required by the I-action with a given input signal (control variable) to
bring about the same change to the manipulated variable as that produced
immediately by the P-action.
The smaller Tn, the steeper/faster the slope.
User manual RVS43.345
The settings in detail
CE1U2354en_021
2013-09-02