Siemens Building Technologies
Basic Documentation RVL470
CE1P2522E / 30.03.2000
Landis & Staefa Division
Function block "Three-position actuator heating circuit"
29/68
9. Function block "Three-position actuator heating circuit"
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)
9.1. Operating lines
Line
Function, parameter
Unit
Factory
setting
Range
81
Maximum limitation of flow temperature
°C
---
--- / 0...140
82
Minimum limitation of flow temperature
°C
---
--- / 0...140
83
Maximum rate of flow temperature increase
°C/h
---
--- / 1...600
84
Excess temperature mixing valve / heat exchanger
°C
10
0...50
85
Actuator running time
s
120
30...873
86
P-band of control (Xp)
°C
32.0
1...100
87
Integral action time of control (Tn)
s
120
30...873
9.2. Limitations
9.2.1. Limitations of the flow temperature
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 ---).
9.2.2. Setpoint increase
t
t
2
5
2
2D
07
T
Vw
T
Vw
Maximum slope =
∆
T
Vw
––––––
∆
t
t
Time
∆
t
Unit of time
T
Vw
Flow temperature setpoint
∆
T
Vw
Setpoint rise per unit of time
