7.11.2 Limitation using 0/4 to 20 mA signal
Depending on the operating situation, a heat meter at input WMZ/Bed (terminals 17/19)
with a 0/4 to 20 mA output (connected in parallel to input WMZ/Bed using 50
Ω
) can be
used to limit the flow rate in the system. All limit values are given in the unit “cubic meters
per hour“ [m
3
/h]. As a result, both a
Lower measuring range value 0 or 4 mA and an Up-
per measuring range value must be set in unit [m
3
/h]. The current flow rate in [m
3
/h] is dis-
played in extended operating level (–> key number 1999).
When the flow rate reaches the current
Max. limit value, the flow set point of control circuit
RK1 is reduced. How strongly the controller responds is determined by the
Limiting factor.
Note!
If CO5 -> F00 - 1 is indicated, access to the return flow, flow rate and heat capacity settings
are locked.
Functions
WE
Configuration
Flow rate limitation (capacity limi-
tation) in RK1 with pulses at input
WMZ
0
CO5 -> F10 - 0
Flow rate limitation in RK1 using
0/4 to 20 mA at input WMZ
0
0
1.5
m
h
3
1.5
m
h
3
1.5
m
h
3
1.5
m
h
3
1.0
CO5 -> F11 - 1
Lower measuring range value / 0, 4 mA
Upper meas. range value 20 mA / 0.01 to 650
m
h
3
Max. limit value / 0.01 to 650
m
h
3
Max. limit value for heating* / 0.01 to 650
m
h
3
Max. limit value for DHW* / 0.01 to 650
m
h
3
Limiting factor / 0.1 to 10.0
Flow rate limitation in RK1 using
the meter bus
0
CO6 -> F11 - 0
* Not in Anl 1.0, 1.5, 1.6, 3.0, 4.0, 7.x, 10.x and 11.x
7.11.3 Creep feed rate limitation using a binary input
It is possible to report to the controller when the creep feed rate has fallen below a certain
level by using a limit switch of the primary valve connected to the input BE13. Either the open
(bE=0) binary input or the closed binary input (bE=1) can be assigned to inform about the
creep feed rate status. Shortly after the alert, the controller closes the valve RK1. As soon as
the flow temperature falls below the set point by more than 5 °C after the valve has been
closed, control operation is started again.
EB 5576 EN
79
System-wide functions
