Siemens CP 1542SP-1 - Analog Value Preprocessing

Configuration and operation
4.5 Telecontrol communication (CP 1542SP-1 IRC)
CP 1542SP-1, CP 1542SP-1 IRC, CP 1543SP-1
74 Operating Instructions, 01/2017, C79000-G8976-C426-03
Integrative method
The integration threshold value calculation works with a cyclic comparison of the integrated
current value with the last stored value. The calculation cycle in which the two values are
compared is 500 milliseconds.
(Note: The calculation cycle must not be confused with the scan cycle of the CPU memory
areas).
The deviations of the current process value are totaled in each calculation cycle. The trigger
is set only when the totaled value reaches the configured value of the threshold value trigger
and a new process value is entered in the send buffer.
The method is explained based on the following example in which a threshold value of 2.0 is
configured.
Table 4- 7 Example of the integration calculation of a threshold value configured with 2.0
Time [s]
(calculation cycle)
Process value
stored in the
send buffer
Current process
value
Absolute deviation
from the stored
value
Integrated devia-
tion
0
20.0
20.0
0
0
0.5 20.3 +0.3 0.3
1.0
19.8
-0.2
0.1
1.5
20.2
+0.2
0.3
2.0
20.5
+0.5
0.8
2.5
20.3
+0.3
1.1
3.0
20.4
+0.4
1.5
3.5
20.5
20.5
+0.5
2.0
4.0
20.4
-0.1
-0.1
4.5
20.1
-0.4
-0.5
5.0
19.9
-0.6
-1.1
5.5
20.1
-0.4
-1.5
6.0
19.9
19.9
-0.6
-2.1
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.
4.5.7.9
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.