Rockwell Automation Allen-Bradley 1769-ASCII, User Manual

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Rockwell Automation Publication 1769-UM012B-EN-P - January 2014 73
I/O Memory Mapping Chapter 3
Alternate Mode (one channel
at a time) Input File One channel’s data is received and stored in the input file at a time. The Channel
Number (CN) bit defines the channel whose data is returned. The alternate
mode input file contains the real-time input data from the module with a header
and data section for each channel. This table illustrates the maximum size
allowed.
Table 6 - Alternate Mode (one channel at a time) Input File Tags
Wo
rd
Bit Position
Add-On-Profile Tag
Name Description
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Generic Module Tag Names
0 Tx ID 0 Acknowledged Rx Transaction ID Ch0 Local:S:I.Ch0TxIACK
(1)
Local:S:I.Ch0RxID
Receive Transaction ID Request. Used with Ch0RxID
for handshake mode.
1 Reserved
(2)
Local:S:I.Ch0Status Ch0 Status. See Status Descriptions on page 76 .
2 Tx ID 1 Acknowledged Rx Transaction ID Ch1 Local:S:I.Ch0TxAck
Local:S:I.Ch0RxID Receive Transaction ID Request. Used with Ch1RxID
for handshake mode.
3 15 14 13 12 11 10 TG1 TS1 ND1 HE1 NR1 RF1 TF1 PA1 RO1 TO1 Local:S:I.Ch1Status Ch1 Status. See Status Descriptions on page 76 .
4 Reserved CNI Local:S:I.RxChNumber Channel number of the input data. This bit is set by
the 1769-ASCII module to tell the user program
from which port the data was received.
5 Reserved CNO Local:S:I.TxChNumber 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.
Firmware Revision, Major Firmware Revision, Minor
6 Length (Number of Bytes) Local:S:I.RxDataLength The amount of data being received.
7 Reserved
8 Character 1 Character 0 Local:S:I.RxData This defines the receive ASCII character for the tag.
9 Character 3 Character 2 Local:S:I.RxData
… Character … Character … Local:S:I.RxData
106 Character 197 Character 196 Local:S:I.RxData
107 Character 199 Character 198 Local:S:I.RxData
(1) Tag name format is `Local:S:I’ where `S’ represents slot number.
(2) Reserved is expected in 1st instance word 0.