Rockwell Automation Allen-Bradley 1769-ASCII, User Manual

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Rockwell Automation Publication 1769-UM012B-EN-P - January 2014 75
I/O Memory Mapping Chapter 3
Simultaneous Mode
(two channels) Output File In simultaneous mode, the data is packed in the buffer as follows:
•
Four words of channel 0 header information
•
Channel 0 data of a quantity defined by the Max_Receive_Size parameter
•
Four words of channel 1 header information
•
Channel 1 data of a quantity defined by the Max_Receive_Size parameter
This table illustrates the maximum size allowed.
Table 8 - Simultaneous Mode (two channels) Output File Tags
Wo
rd
Bit Position
Add-On-Profile Tag
Name Descriptions
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Channel 0 Data
Generic Module Tag Names
0 Reserved
(1)
Tx Transaction ID Local:S:O.Ch0TxId Transmit Transaction ID.
1 Reserved Rx Transaction ID Request Local:S:O.Ch0RxId
(2)
Receive Transaction ID Request. Used with
Ch1RxID for handshake mode.
2 Reserved
3 Length (Number of Bytes) Local:S:O.Ch0TxDataLength The amount of data being transmitted.
4 Character 1 Character 0 Local:S:O.Ch0TxData This defines the transmit ASCII character for
the tag.
5 Character 3 Character 2 Local:S:O.Ch0TxData
… Character … Character … Local:S:O.Ch0TxData
x
(3)
Last Character Character … Local:S:O.Ch0TxData
Channel 1 Data
x+1 Reserved Tx Transaction ID Local:S:O.Ch1TxId Transmit Transaction ID.
x+2 Reserved Rx Transaction ID Request Local:S:O.Ch1RxId
(4)
Receive Transaction ID Request. Used with
Ch0RxID for handshake mode.
x+3 Reserved
x+4 Length (Number of Bytes) Local:S:O.Ch1TxDataLength The amount of data being transmitted.
x+5 Character 1 Character 0 Local:S:O.Ch1TxData This defines the transmit ASCII character for
the tag.
x+6 Character 3 Character 2 Local:S:O.Ch1TxData
… Character … Character … Local:S:O.Ch1TxData
y
(5)
Last Character Character … Local:S:O.Ch1TxData
(1) Reserved is expected in 1st instance word 0.
(2) Used for handshaking.
(3) X is calculated based on the size of Channel 0 data as specified in the configuration file. Both channels cannot contain 200 characters as the total configuration size can be only 108 words.
(4) Used for handshaking.
(5) Y is equal to the connection size minus 1, with a maximum value of 107 for a buffer size of 108.