Siemens SIMATIC ET 200AL, System Manual

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Programming
4.3 Time-based IO
High-precision input/output with Time-based IO
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Function Manual, 11/2019, A5E33454822-AC
4.3.2 TIO_DI: Reading in edges at digital input and associated time stamps
Description
TIO_DI continuously detects the edges at a digital input of a TIO module and returns the
associated time stamps.
Startup characteristics
During startup of the CPU, the instruction TIO_DI applies the input parameters once and
checks the following:
● Checking HWID
● Checking to see if the number of the digital input (Channel) is in the permitted range
(depending on addressed module and channel configuration)
● Checking TIO_SYNC_Data.ERROR: Is an error present at TIO_SYNC?
● Checking TIO_SYNC_Data.TO_TIMES for plausibility (0 ms to 4 ms)
● Checking to see whether the OB is isochronous
If startup takes place without errors, the instruction changes to normal operation. In the event
of an error, the instruction does not change to normal operation and generates an error
message.
Functional description
In normal operation, the instruction detects the edges at a digital input and the associated
time stamps of the last valid, defined edge pair from the preceding isochronous cycle. Use
the input parameter EdgeSel to determine the edges for which time stamps are detected.
You connect the input TIO_SYNC_Data with the output of the same name of the TIO_SYNC
instruction. This ensures a shared time basis.