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Siemens
Switching and monitoring device RMS705B
CE1P3124en
Building Technologies
Aggregates
01.04.2010
8.3
Rotary step switch
Use this function to control multi-stage aggregates depending on load
or
control
several aggregates and be used as lead/lag control.
You can configure the rotary step switch using a selectable step switch type (3
types available for selection).
T
he rotary step switch can be configured as:
Linear step switch
- Switch equal stages
or
aggregates with equal output (max.4 per function
block).
- Lead/lag control (run priority changeover) with selectable changeover types for
the same number of operating hours.
Flexible step switch
Optimum switching of aggregates with different outputs to ensure that as few
aggregates as possible are operating and to achieve optimum control under
partial load conditions (max. 4 stages).
Binary step switch
Switching binary stepped aggregates. Max 15 stages can be switched per step
switch. 2 step switches combined can switch max. 127 stages.
Only the linear step switch allows for lead/lag control (run priority changeover).
Inputs
C D
C
D
Rotary
step switch 1
Outputs
Input
Section
Output
Section
Precommand
8.3.8
Precommand
8.3.7
2
t
1
Star
Start conditions 1,2,3,4, and
co i
8.3.11
nt nuous
Command
8.3.5
Fault status message aggregates
8.3.12
A,B,C,D
Load
8.3.6
Explanation of symbols
Purpose
Note