Rockwell Automation Publication 1769-IN088A-EN-P - February 2011 181
I/O Memory Mapping Chapter 3
• NR = Non-delimited record. An input record is received and sent to the
Compact bus interface that was not triggered by a delimiter character. This
occurs when either the buffer is filled to its maximum receive size or a
Message Timeout has occurred.
• RF = Data in the receive FIFO. The FIFO is not empty. The input FIFO
has not sent all of its data to the Compact bus interface.
• TF = Data in transmit FIFO. The FIFO is not empty. The output FIFO
has not sent all of its data to the ASCII device.
• PA = Parity error. A parity error has occurred with the received data string.
This usually indicates a mismatch in the serial port set-up of the ASCII
device and the Compact module. It could also indicate that noise has
occurred on the line and degraded the signal. This bit is set when the
receive FIFO contains a message in which a parity error occurred in one of
the incoming bytes. This bit is reset when the receive FIFO is emptied or
when a new message is received with no parity error.
• RO = Receive buffer overflow. Some input data has been lost.
• TG = Transmit greater than Max Error. Transmit length in the output file
is greater than the maximum transmit character length in the
configuration file.
• TO = Transmit buffer overflow. Some output data has been lost.
• CNI = Channel number of the input data. This bit is set by the ASCII
module to tell the user program from which port the data was received.
• CNO = Channel number of the output data most recently received. This
bit is set by the ASCII module to tell the user program that it has received
the data to transmit out the specified port.
Alternate Mode (One Channel at a Time) Output File
Maximum size is shown below. Refer to the Compact I/O 1769-ASCII Module
User Manual, publication 1769-UM012
, to use smaller output files.
Word
Bit Position
1514131211109876543210
0 Reserved Tx Transaction ID Ch0
1 Reserved Rx Transaction ID Request Ch0
2 Reserved Tx Transaction ID Ch1
3 Reserved Rx Transaction ID Request Ch1
4 Reserved CNI
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