8.4
Variable step switch (STEP Vx)
8.4.1
Purpose and activation
The STEP Vx (variable step switch) function block switches multi-stage
aggregates. All outputs can be set individually.
Purpose of STEP Vx
Depending on the type of controller, the following number of variable step switches
are available:
Number
Controller
type
Number of variable step switches
RLU202
1 = with a maximum of 2 steps
RLU202 None
RLU222
1 = with a maximum of 2 steps
RLU232
1 = with a maximum of 2 steps
RLU236
1 = with a maximum of 6 steps
1 = with a maximum of 2 steps (6 relays available
in total)
To activate the variable step switch, assign a relay Q… to the STEP 1 output.
Activation
Note
Additionally, you can also configure the available analog output AO with each step
switch. The same settings are possible as with the modulating output, AO function
block. Accordingly, a Y output can also be assigned.
8.4.2
Operating principle
With variable step switching, you can set the digital outputs individually according
to the load.
Load connection
You can define the digital output's direction of action via the switching point
settings. The digital outputs can overlap each other.
Example
The following diagram shows an example of load connection.
0 %
31
01
D
17
20 %
40 %
60 %
20%
80 %
S1-ON > S1-OFF
S2-ON < S2-OFF
MAX POS
MIN POS
Q
Y+Q
S2-ON
S2-OFF
S1-ON
S1-OFF
AO
100 %
STEP 1
STEP 2
If the step switch is controlled by 2 internal sequence controllers, the larger signal
is effective (maximum selection).
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Siemens
Universal Controllers RLU2…
CE1P3101en
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29.08.2008