Siemens Synco 200 - Binary Step Switch (STEPBIN)

8.6 Binary step switch (STEPBIN)
8.6.1 Purpose and activation
The STEPBIN (binary step switch) function block switches multi-stage aggregates.
The aggregates must be sized according to the binary load distribution.
Purpose of STEPBIN
Depending on the type of controller, the following number of binary step switches
are available:
Number
Controller
type
Number of binary step switches
RLU202 None
RLU202 None
RLU222 None
RLU232 1 binary step switch with a maximum
of:
– 2 relay outputs(= 3 load steps)
– 1 modulating output
RLU236 1 binary step switch with a maximum
of:
– 4 relay outputs(= 15 load steps)
– 1 modulating output
To activate the binary step switch, assign a relay Q… to the STEP 1 output.
Activation
8.6.2 Operating principle
The binary step switch distributes the digital outputs with the number of load steps
according to the following table over the total contact rating of the aggregate.
Load distribution
(demand calculation)
a) If configured without the analog output:
Load distribution
Configured
outputs
Relay 1 Relay 2 Relay 3 Relay 4
Number of
load steps
0Y+2Q Q1 = 1/3 Q2 = 2/3 3
0Y+3Q Q1 = 1/7 Q2 = 2/7 Q3 = 4/7 7
0Y+4Q Q1 = 1/15 Q2 = 2/15 Q3 = 4/15 Q4 = 8/15 15
b) If configured with an analog output:
Load distribution
Configured
outputs
Y Relay 1 Relay 2 Relay 3 Relay 4
Number of
load steps
1Y+2Q Y= 1/4 Q1= 1/4 Q2= 2/4 4
1Y+3Q Y= 1/8 Q1= 1/8 Q3= 2/8 Q3= 4/8 8
1Y+4Q Y= 1/16 Q1=1/1
6
Q2=2/1
6
Q3=4/1
6
Q4=8/1
6
16
0Y = no analog output
Explanation
1Y = 1 analog output
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Siemens Universal Controllers RLU2… CE1P3101en
Building Technologies Aggregates 29.08.2008