Siemens Simatic RTU3030C, Руководство по эксплуатации

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Program blocks
5.7 Blocks for analog value functions
RTU303xC
Operating Instructions, 06/2019, C79000-G8976-C382-06
285
Block functions
The two functions of the block depend on the position of the threshold value compared with
the Limit value:
● Window (range monitoring)
"Function" = "+ (window)"
Limit value < Input signal < Threshold value
A range of the analog value (window) between limit value and threshold value is
monitored.
Two applications are possible:
–
Output = 1, when input signal is within the window.
For the operating diagram see Limit value switch.
– Output = 0, when input signal is outside the window.
For this functionality you need to invert the "Output" using the black contact symbol.
● Limit value with hysteresis
"Function" = "+ (hysteresis)"
Threshold value < Limit value
The limit value is given a hysteresis for example to control a pump.
Two applications are possible:
–
Limit value
high
with negative hysteresis
When the input signal exceeds the limit value the output is set to 1.
When the input signal falls below the threshold value the output is set to 0.
– Limit value
low
with positive hysteresis
You can monitor the input signal for a limit value
low
with positive hysteresis if you
invert the input signal (x) using the black contact symbol (1/x).
Parameters
Parameters Tag type / range of
values
Description
Input parameters
En
Enable parameter, see section Often used parame-
ters (Page 252).
Input
• Analog input / bit
memory
•
Event counter /
usage meter
The value of the input is monitored for the limit
value and a threshold value by the block.