Analog Value Preprocessing - Siemens CP 1243-1 Operating Instructions Manual

Table 4- 7
(calculation cycle)
With the changes in the process value shown in the example, the threshold value trigger
configured with 2.0 fires twice:
● At the time 3.5 s: The value of the integrated deviation is at 2.0. The new process value
stored in the send buffer is 20.5.
● At the time 6.0 s: The value of the integrated deviation is at 2.1. The new process value
stored in the send buffer is 19.9.
In this example, if a deviation of the process value of approximately 0.5 should fire the
trigger, then with the behavior of the process value shown here a threshold value of
approximately 1.5 ... 2.5 would need to be configured.
4.10.10

Analog value preprocessing

CPs with data point configuration support analog value preprocessing. For analog value data
points, some or all of the functions described below can be configured.
Requirements and restrictions
You will find the requirements for the configuration of the preprocessing options and
restrictions in the section relating to the particular function.
Note
Restrictions due to configured triggers
The analog value preprocessing options "Fault suppression time", "Limit value calculation"
and "smoothing" are not performed if no threshold value trigger is configured for the relevant
data point.. In these cases, the read process value of the data point is entered in the image
memory of the CP before the preprocessing cycle of the threshold value calculation (500 ms)
elapses.
CP 1243-1
Operating Instructions, 04/2017, C79000-G8976-C365-03
Example of the integration calculation of a threshold value configured with 2.0
Time [s] Process value
stored in the
send buffer
0 20.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5 20.5
4.0
4.5
5.0
5.5
6.0 19.9
Current process Absolute deviation
value from the stored
20.0
20.3
19.8
20.2
20.5
20.3
20.4
20.5
20.4
20.1
19.9
20.1
19.9
Configuration
4.10 Data points
Integrated devia-
tion
value
0 0
+0.3 0.3
-0.2 0.1
+0.2 0.3
+0.5 0.8
+0.3 1.1
+0.4 1.5
+0.5 2.0
-0.1 -0.1
-0.4 -0.5
-0.6 -1.1
-0.4 -1.5
-0.6 -2.1
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