Siemens Simatic RTU303xC Series Operating Instructions Manual page 282

Program blocks
5.7 Blocks for analog value functions
From the arrangement of the two function parameters "Limit value 1" and "Limit value 2" the
function provides:
● Limit value with hysteresis
Limit 1 ≥ Limit 2
The limit value is given a hysteresis for example to control a pump.
Two applications are possible:
– Limit value
– Limit value
● Window (range monitoring)
Limit value 1" < Input signal < "Limit value 2
A range of the analog value (window) between "Limit value 1" and "Limit value 2" is
monitored.
– Output = 1, when input signal is within the window.
– Output = 0, when input signal is within the window.
282
with negative hysteresis
high
When the input signal exceeds "Limit value 1" the output is set to 1.
When the input signal falls below "Limit value 2" the output is set to 0.
Figure 5-6 Operating diagram of an example of limit value
with positive hysteresis
low
You can monitor the input signal for a limit value
invert the input signal (x) using the black contact symbol (1/x).
For information on inverting, see section Parameter assignment of the blocks
(Page 251).
Figure 5-7 Operating diagram of an example of the window function
For this functionality you need to invert the "Output" using the black contact symbol.
with negative hysteresis
high
with positive hysteresis if you
low
Operating Instructions, 06/2019, C79000-G8976-C382-06
RTU303xC