7.11.1 Limitation using pulse input
Depending on the operating situation, a heat meter with pulse output connected to input
WMZ/Bed (terminals 17/19) can be used to limit either the flow rate or the capacity in the
system. All limit values are given in the unit “pulses per hour“ [pulse/h]. As a result, the con-
troller does not distinguish between a flow rate pulse signal or a capacity pulse signal. As
the displayed current pulse rate P [pulse/h] (–> Extended operating level, key number 1999)
is calculated depending on the interval between the received pulses, it is natural that the con-
troller cannot react immediately to all rapid flow rate or capacity changes which occur in the
system.
When the pulse rate reaches the current
Max. limit value
, the flow set point of control cir-
cuit Rk1 is reduced. How strongly the controller responds is determined by the
Limiting fac-
tor
.
Example to determine the limit value:
If a capacity of 30 kW is to be limited, the following limit value must be set for a heat meter
with an output of one pulse per kilowatt-hour:
P
30 kW
1KWh/pulse
30 pulse / h==
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
15
pulse
h
15
pulse
h
15
pulse
h
1.0
CO5 -> F10 - 1
Max. limit value / 3 to 500
pulse
h
Max. limit value for heating* / 3 to 500
pulse
h
Max. limit value for DHW* / 3 to 500
pulse
h
Limiting factor / 0.1 to 10.0
Flow rate limitation in Rk1 with
0/4 to 20 mA at input WMZ
0 CO5 -> F11 - 0
Capacity limitation in Rk1 using
the meter bus
0 CO6 -> F12 - 0
* Not in Anl 1.0, 1.5, 1.6, 3.0, 3.5, 4.0, 7.x, 10.x, 11.x,
12.x, 13.x, 21.x and 25.0
102 EB 5579 EN
System-wide functions
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