Tio_Di: Reading In Edges At Digital Input And Associated Time Stamps - Siemens SIMATIC ET 200AL System Manual

Programming
4.3 Time-based IO
4.3.3

TIO_DI: Reading in edges at digital input and associated time stamps

Description
You can use the Time-based IO with the TIO_DI instruction. TIO_DI continuously detects the
edges at a digital input of a TM Timer DIDQ 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 T
● Checking whether the OB is a "Synchronous Cycle" OB
If startup takes place without errors, the instruction changes to normal operation. The input
parameter EdgeSel can be changed during normal operation. In the event of an error, the
instruction does not change to normal operation and generates an error message.
Operating principle
In normal operation, the instruction detects the edges at a digital input and the associated
time stamps (time = TIO_Time) of the last valid, defined edge pair. 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.
Reaction to error
The Error output indicates if the instruction was processed correctly. The reasons for the
errors are displayed at the Status output.
42
for validity (0 ms to 4 ms)
o
High-precision input/output with Time-based IO
Function Manual, 08/2014, A5E33454822-AB