Siemens Simatic ET 200MP Manual page 49

Structure of data record 0 of the Counting mode
The example in the figure below shows the structure of data record 0 for channel 0. The
structure of channel 1 is identical, the values are located in data record 1.
The values in byte 0 and byte 1 are fixed and may not be changed.
Enable a parameter by setting the corresponding bit to "1".
Figure B-2 Structure of data record 0: Bytes 0 to 4
DI 32x24VDC HF digital input module (6ES7521-1BL00-0AB0)
Manual, 09/2016, A5E03485935-AF
B.3 Structure of the parameter data records Counting mode
Parameter data records
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