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5-7SectionUsing Protocol Macros
92
Time Lag t1
Baud rate (b/s) Lag time (ms)
1,200 30
2,400 15
4,800 8
9,600 5
19,200 3
Note The lag time shown above is an approximate value. It may become longer de-
pending on the protocol macro processing.
Error Flags for Overrun, Framing, and Parity Errors
When an overrun, framing, or parity error is detected during a protocol macro,
the receive data will be stored in the reception buffer along with error informa-
tion. The error flags will operate as described next.
Receive Data with Error Information that Matches Expected Receive Mes-
sages
The expected receive message received for the RECEIVE operation is found in
the reception buffer and handled as receive data. If the receive data contains
error information, the corresponding error flags are turned ON.
The following example shows reception of 100 bytes of data that matches an
expected receive message.
Error flags ON
Parity errors
100 bytes
Receive Data with Error Information that Does Not Match Expected Re-
ceive Messages
If there is no expected receive message that matches the receive data, the data
is discarded and the error flags are not affected. The trace information will con-
tain any error information entering the reception buffer up to the capacity of the
trace data.
The following example illustrated what happens when there is no expected re-
ceive message that matches the receive data.
Discarded
Error flags are not changed.
In the following ladder programming, sequence number 000 (E5jK Digital Con-
troller Read
) is executed through PMCR(––) to read the PV from the Digital Con-