JUMO mTRON T Manual page 53

4.3.3 End identifier conditions
The 3S definitions contain all the necessary end identifier conditions, which are required for
building a package when receiving individual characters:
• Length in bytes
is transmitted as parameter uiSize for ComRead()
= max. buffer size to disable the length as the end condition
• Response time-out in milliseconds
is transmitted as parameter ulTimeout for ComRead()
= "SYS_NOWAIT" = 0 (endless) to disable the time-out
• Character time-out in milliseconds
is transmitted in parameter pSettings for ComSetSettings() or as parameter ulTimeout for
ComSetTimeout()
= "SYS_NOWAIT" = 0 (endless) to disable the time-out
Complete packages are already transmitted character by character in the background during
transmission. The ComWrite() function immediately ends without blocking (parameter
ulTimeout is ignored).
4.3.4 Protocol scenarios
All usual applications can be covered with the defined end identifier conditions.
PLC as a master
A master starts with the transmission and then waits for a limited time (response time-out) for
the response of the addressed slave.
The parameters for the end identifier conditions must be set as follows:
possibly: length = x bytes
response time-out T1 = 2000 ms (example)
possibly: character time-out T2 = y ms
One of the two conditions – length or character time-out – must be set so that a started re-
sponse package can be detected as completed.
4 Serial transmission modes
T1 T2
O K
T1
O K
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