Siemens S7-1200 Operating Instructions Manual page 83

Set limit value 'low' / Set limit value 'high'
In these two input boxes, you can set a limit value in the direction of the start of the
measuring range or in the direction of the end of the measuring range. You can also
evaluate the limit values, for example as the start or end of the measuring range.
If the limit value is overshot or undershot, the status identifier "OVER_RANGE" of the data
point is set. This status identifiers are described in the section Status IDs of data points
(Page 54).
The "OVER_RANGE" bit of the status identifier of the data point is set as follows when the
relevant analog value is transferred:
● Limit value 'high':
– If the limit value is exceeded: OVER_RANGE = 1
– If the value falls below the limit value: OVER_RANGE = 0
● Limit value 'low':
– If the value falls below the limit value : OVER_RANGE = 1
– If the value then exceeds the limit value: OVER_RANGE = 0
Requirements for the function
● Configuration of the threshold trigger for this data point
● PLC tag in the bit memory operand area or data area
The analog value data point must be linked to a PLC tag in the bit memory or data area
(data block). For hardware modules (input operand area) limit value configuration is not
possible.
The configuration of limit values is pointless for measured values that have already been
preprocessed on the CPU.
CP 1243-7 LTE
Operating Instructions, 01/2015, C79000-G8976-C381-01
4.15 STEP 7 configuration of individual parameters
Configuration and operation
83