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Siemens Building Technologies
Basic Dokumentation RVA63.280, RVA53.280
CE1P2374E
Landis & Staefa Division
19.04.2001
3.17
Switching differential of actuator
Optimum control of 2-position mixing valve.
For a 2-position actuator, a switching differential can be adjusted, allowing the 2-
position control to be optimally matched to the type of actuator used.
The actuator’s mode of control on setting line 35
OEM
must be set to "2-position“.
Setting range
Unit
Factory setting
0...20
°C (K)
2
This setting changes the switching differential of mixing valve actuator Y1.
Entry:
Increase:
Switching differential will become larger
Fewer and longer heating up times, larger temperature variations.
Greater temperature variations in the heating circuit.
Decrease:
Switching differential will become smaller
More frequent and shorter heating up times, smaller temperature
variations.
Smaller temperature variations in the heating circuit.
3.17.1
Control of mixing valve actuator
2-position control provides control of the motorized mixing valve by delivering pulses.
Generally, this means: The greater the amount of heat needed, the longer the heating
up time.
Y
°C
TVx
TVw+SDM/2
2373
D
0
1
TVw-SDM/2
t
TVw
Legend
TVx
Actual value of the flow
temperature
TVw
Flow temperature setpoint
SDM
Switching differential of actuator
Y
Mixing valve actuator OPENS
Y
Mixing valve actuator CLOSES
Mixing valve actuator OPENS
=
TVw - SDM/2
Motorized valve actuator CLOSES
=
TVw + SDM/2
°C
237
3
D
0
2
w
ON
OFF
w
Setpoint
36OEM
Switching differential of
actuator
Switch-on point
Switch-off point
ON
Mixing valve actuator
OPENS
OFF
Mixing valve actuator
CLOSES
Benefit
Description
Important
Setting
Effect
Switching differential