16
Compact 1769-ASCII Module
Publication
1769-IN068B-EN-P - May 2005
I/O Memory Mapping
The 1769-ASCII module supports an input assembly that is accessible
through the Assembly Object (Class 4), Instance 101. The input assembly is
up to 108 words. The module supports an output assembly that is accessible
through the Assembly Object (Class 4), Instance 100. The output assembly is
up to 108 words.
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.
•
Tx = Transmit
•
Rx = Receive
•
CNI = Channel number of requested input data. This bit is set by the
PLC controller or other user program to tell the ASCII module which
data to produce.
Wo
rd
Bit Position
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
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
5
Reserved
CNO
6
Reserved
7
Length (Number of Bytes)
8
Character 1
Character 0
9
Character 3
Character 2
…
Character …
Character …
106
Character 197
Character 196
107
Character 199
Character 198