Basic Documentation

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Siemens Universal controllers RMU710B, RMU720B, RMU730B CE1P3150en
Building Technologies Flow temperature, demand-controlled (basic type C) 03.10.2011
13.6 Request signals
13.6.1 Possible chilled water request signals
The following request signals can be handled depending on the main control loop:
 Valve position (e.g. from RMU7..B control as basic type A for an air handling
plant with a cooling coil) via the bus
 Refrigeration demand in % (e.g. from individual room control "Cooling coil") via
the bus
 Refrigeration demand in °C (e.g. from RMU7...B main chilled water control as
basic type C) via the bus
 Refrigeration demand as digital input (see section 6.6 "Plant operating mode
sele
ction via request input (basic type P, C)")
All of these signals can be handled simultaneously.
Request signal "Valve position in %"
This request signal can be sent by a controller RMU7..B basic type A or U or by an
RXB room controller. The signal can be handled by any number of controllers.
The only condition is that all of them have the same chilled water distribution zone
set. With 2-pipe systems, the same hot water distribution zone must also be set.
The type of maximum selection is made via the demand signals. The type of
maximum selection can be set.
 Maximum: For shifting, only the largest signal is considered
 Average: For shifting, the 4 largest signals are considered. These 4 values are
used to generate an average signal
The controller controls the valve position to 90% by increasing the flow
temperature based on the set "Chilled water flow setpoint" by the set "Flow
temperature increase max".
The control action can be matched to the type of plant.
The following settings are possible:
 Slow
 Medium
 Fast
Main menu > Commissioning > Settings > .... or
Main menu > Settings > Controller 1 > Setpoints >
Operating line Range Factory setting
Control action Slow, Medium, Fast Medium
Request evaluation Maximum, Average Maximum
Refrigeration request signal in °C
This request signal can be set by a controller RMU7..B basic type C. A chilled
water flow temperature setpoint is predefined for the controller via this signal. On
the controller, the predefined setpoint can be limited via the settings "Chilled water
flow setpoint" and "Flow temperature increase max"; universal setpoint shift may
not be activated.
If the request signal is only used as a switch-on/switch-off command of the primary
controller, a chilled water flow setpoint can be predefined; in addition, this setpoint
can be shifted by using the universal shift, and setting value "Flow temperature
increase max" must be set to "OK".
Condition
Setting values