User Manual

The "Control action" of the flow temperature on the setpoint shifts can be set in
three steps ("Fast", "Medium", "Slow") to adapt to the plant.
Control actio
n
Use setting "
Request evaluation" to determine if the max value or the average of
the requests is to be used.
Req
uest evaluation

When using the "Maximum" setting, the flow temperature is readjusted so that
the valve position for the consumer with the greatest heat demand is 90%.
 When using the "Average" setting, the flow temperature is readjusted so that the
valve positions of the 4 largest consumers are 90% on average
Note: This setting does not ensure that all consumers can cover their heat
demand. It prevents, however, an individual consumer from forcing the flow
temperature to high levels (e.g. because a window was left open).
10.1.5 Internal heat demand
RMS705B provides the calculated request signals as internal signals. To this end,
function block "Heat demand" offers two outputs.
Purpo
se and function
 (
d)
The demand as a digital value, e.g. via a motor block, logic block, etc., can be
further handled, e.g., to switch on a pump when a heat demand signal was sent.
 (
a)
For example, as demand-dependent setpoint for setpoint shift or as DC 0..10 V
temperature signal.
10.1.6 Heat demand relay (Q )
Release for an external heat source, for example, can be connected to this output.
Purpo
se and function
The heat de
mand relay responds as soon as the bus requests "heat".
Meaning:
 Contact open = No heat demand.
 Contact closed = Heat demand
Main menu > Commissioning > Extra configuration > Aggregates > Heat demand >
Config
uration
Operating lin
e Adjustable values / Comment
Heat demand relay ---, N.Q1, N.Q3, ... / Enable output.
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Siemens Switching and monitoring device RMS705B CE1P3124en
Building Technologies H/C demand, H/C changeover 01.04.2010