Basic Documentation

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Siemens Modular Heating Controller RMH760B CE1P3133en
Building Technologies 9 Heating circuit control 2017-09-29
The meter input is an input of function block "Meter" used for the limitation of pulses.
Only inputs configured to a terminal can be selected.
There are 2 types of limitation to choose from:
• Absolute: Limitation takes effect when the limit value is crossed
• Scaled: The limit value is fixed at 75 pulses/min. It can be adjusted but without
having any effect. If less than 5 pulses/min are received, fault status message No
signal meter 1 (or …2) will be delivered after 20 seconds. Heat meters with a scaled
output deliver 120 pulses/min if there is no supply of heat or no volumetric flow. Used
together with pulse limitation, this prevents hydraulic creep.
From the limit value, pulse limitation starts throttling the actuating device (mixing valve).
The setting is only active when the limitation is absolute. With the scaled limitation, the
limit value can be set, but the function is always performed with 75 pulses/min (fixed
value).
The setting value determines the rate at which the flow temperature setpoint will be
lowered:
• Short integral action times lead to fast reductions
• Long integral action times lead to slow reductions
9.8.6 Pump overrun and mixing valve overrun
To protect the boiler against overtemperatures after the burner has shut down, a
consumer overrun time can be set on the boiler controller.
9.8.7 Pump kick and valve kick
The pump kick is a protective function that is carried out periodically. It prevents pumps
and / or mixing valves from seizing after longer off periods.
9.9 Heat demand
The heating circuit sends its heat demand as a temperature request to the heat source.
T
T
3131B15
T
Heat
consumer
Heat
source
Heat
consumer
Leistungssteuerung
Wärmebedarf
The temperature request for the current heat demand is calculated based on the flow
temperature setpoint of the heating circuit (heating curve, subsection 9.5.2, and
influences, subsection 9.5.3) plus an adjustable setpoint increase for the mixing valve.
Meter input
Type of limitation
Limit value
Integral action time (Tn)