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 currrent pulse rate P [pulse/h] (–> Extended operating level, key num-
ber 1999) is calculated depending on the interval between the received pulses, it is natural
that the controller 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
circuit RK1 is reduced. How strongly the controller responds is determined by the
Limiting
factor.
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
1 KWh / 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, 4.0, 7.x, 10.x and 11.x
78
EB 5576 EN
System-wide functions
