Gain Of Locking Signal - Siemens RVL471 Basic Documentation

Example
Fundamentals
Uncritical locking
signals
Critical locking signals
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HVAC Products
made is the earliest possible changeover date. The weekday on which changeover
occurs is always a Sunday.
If the start of summertime is given as "The last Sunday in March", the earliest possible
changeover date is March 25. The date to be entered on operating line 176 is then
25.03.
If no summer- / wintertime changeover is required, the two dates are to be set such that
they coincide.
25.4.7

Gain of locking signal

The functions "Maintained boiler return temperature", "Protective boiler start-up" and
"D.h.w. priority" use locking signals that are sent to the heat exchangers and loads.
With the heat convector and load controllers, it is possible to set on operating line 173
(amplification of locking signal) to what degree they shall respond to a locking signal.
This gain of the locking signal is adjustable from 0 % to 200 %.
Setting Response
0 % Locking signal will be ignored
100 % Locking signal will be adopted 1:1
200 % Locking signal will be doubled
There are 2 types of locking signals:
• Uncritical locking signals
• Critical locking signals
The response of the loads depends on the kind of load.
Uncritical locking signals are generated in connection with the d.h.w. priority (absolute
and shifting) and only act on the heating circuits.
The response of the heating circuit depends on the type of heating circuit:
• Heating circuit with mixing valve:
In the heating circuit, the flow temperature setpoint will be reduced as a function of the
set locking signal gain. The mixing valve closes.
• Heating circuit with pump:
In case of a defined value of the uncritical locking signal, the heating circuit pump will
be deactivated, independent of the set locking signal gain. In plants with changeover
valve, the valve assumes the "D.h.w." position
Critical locking signals are generated by the boiler temperature controller during protec-
tive boiler startup and during minimum limitation of the boiler return temperature. If the
boiler temperature controller is located in segment 0, the critical locking signal will be
sent to all loads and heat exchangers in the bus network and – if present – to its own
heating and d.h.w. circuit. If the boiler temperature controller is in segment 1...14, it will
deliver the critical locking signal only to all loads in the same segment and – if present –
to its own heating and d.h.w. circuit.
Minimum limitation of the return temperature can also be provided locally by a controller
with plant type no. 1–x. In that case, the critical locking signal only acts inside the con-
troller and is only delivered to the own heating and d.h.w. circuit.
With regard to the response of the consumers and heat converters, there are two
choices:
• Heat converters and consumers with mixing valves:
The flow temperature setpoint will be reduced as a function of the set locking signal
gain. Heat exchanger and load close their mixing valve.
• Consumers with pump circuit:
When a defined value of the critical locking signal is reached, the pump will be deacti-
vated, independent of the set locking signal gain In plants with changeover valve, the
valve assumes the "Heating circuit" position
Basic Documentation RVL471
25 Function block "Service functions and general settings"
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CE1P2524E
23.10.2002