Siemens S7-1200 Operating Instructions Manual page 80

Configuration and operation
4.15 STEP 7 configuration of individual parameters
Sequence of processing Threshold value trigger and Analog value preprocessing
Note
Threshold value trigger: Calculation only after "Analog value preprocessing"
Note that the analog value preprocessing is performed before the check for a configured
threshold value.
This affects the value that is configured for the threshold value trigger.
Restricted preprocessing options if mean value generation is configured
If you configure mean value generation for an analog value event, the following
preprocessing options are not available:
• Unipolar transfer
• Fault suppression time
• Smoothing
No Threshold value trigger if Mean value generation is configured
If mean value generation is configured, no threshold value trigger can be configured for the
analog value event involved.
Analog inputs that are configured as an event are processed on the CP in the following
sequence:
Sequence of analog value processing
1. Reading the data from the input area of the CPU
2. Analog value preprocessing (part 1)
Processing involves the following steps:
– Mean value generation
– Unipolar transfer (if configured)
– Fault suppression time (if configured)
– Smoothing (if configured)
3. Threshold value calculation (if Threshold value trigger is configured)
4. Analog value preprocessing (part 2)
– Set limit value 'low' / Set limit value 'high' (if configured)
5. Storage of the value in the send buffer
Transfer of the value to the partner if trigger and threshold value conditions are met.
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- Mean value generation configured: Calculation and then continued at point 4.
- No mean value generation configured: Continue with "Unipolar transfer".
Operating Instructions, 01/2015, C79000-G8976-C381-01
CP 1243-7 LTE