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9. Function block "Three-position actuator heating circuit"
9.1. Operating lines
9.2. Limitations
9.2.1. Limitations of the flow temperature
9.2.2. Setpoint increase
Siemens Building Technologies
Landis & Staefa Division
This function block provides three-position control. Depending on the type of plant, it
acts as follows:
•
Weather-compensated, on the mixing valve of a space heating system
(plant type 1)
•
Weather-compensated, on the valve in the primary return of a space heating
system with a district heat connection (plant type 3)
•
Demand-compensated, on the mixing valve of a main flow (plant type 4)
•
Demand-compensated, on the valve in the primary return of a main flow with a district
heat connection (plant type 6)
Line
Function, parameter
81
Maximum limitation of flow temperature
82
Minimum limitation of flow temperature
83
Maximum rate of flow temperature increase
84
Excess temperature mixing valve / heat exchanger
85
Actuator running time
86
P-band of control (Xp)
Integral action time of control (Tn)
87
The following limitations can be set:
•
Maximum limitation of flow temperature: at the limit value, the heating curve runs hori-
zontal. This means that the flow temperature setpoint cannot exceed the maximum
value
•
Minimum limitation of flow temperature: at the limit value, the heating curve runs hori-
zontal. This means that the flow temperature setpoint cannot fall below the minimum
value
If the setpoint is limited, the display shows:
= for maximum limitation
= for minimum limitation
Both limitations can be deactivated (setting ---).
T
Vw
t
t
Time
∆t
Unit of time
T
Flow temperature setpoint
Vw
∆T
Setpoint rise per unit of time
Vw
Basic Documentation RVL470
Function block "Three-position actuator heating circuit"
Unit
°C
°C
°C/h
°C
s
°C
s
Maximum slope =
T
Vw
t
Factory
Range
setting
---
--- / 0...140
---
--- / 0...140
---
--- / 1...600
10
0...50
120
30...873
32.0
1...100
120
30...873
∆T
Vw
––––––
∆t
CE1P2522E / 30.03.2000
29/68
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