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Chapter 3
Module Tag Definitions
28
The default value for Pad Mode is ON. If your scanner does support variable
I/O messaging lengths, you can turn OFF the Pad Mode option (a value of 0) to
conserve some network bandwidth.
The selection of Pad Mode is valid only for the Ethernet message that the ASCII
module produces. It has no effect on Ethernet messages that are sent from the
scanner to the ASCII module. This value can be set and retrieved by using the
standard set and get services on Class 15 (F
Pad Mode Character
The ASCII modules allow you to specify the character that Pad Mode uses to
pad the received serial data. This can be set to any valid I/O value (0...127 in 7-
bit modes, 0...255 in 8-bit modes). This value can be set and retrieved by using
the standard set and get services on Class 15 (F
Set Up and Use the Swap Bytes Mode
This option is helpful if the ASCII module is connected to a controller that
organizes the data string characters into data type elements that are larger
than 1 byte each. In such cases, the bytes of the data in the master's memory
organization can be reversed from the order in which they are sent or received
in the controller's serial link to the ASCII device. This can cause errors in some
cases. Thus, the received string "ABCDEFGH" may appear in memory as
"BADCFEHG" for 2-byte word organization, and "DCBAHGFE" for 4-byte word
organization.
Transmit Byte Swapping
By setting Parameter 21 (Class F
swaps the bytes from the master before transmitting the string to the ASCII
device.
To swap bytes from the master, set the Byte Swap mode from the Transmit
Data section of the Advance Format Configuration Category. See
Format Configuration Category on page
Receive Byte Swapping
By setting Parameter 11 (Class F
reorders the bytes received from your ASCII device before sending the string
to the master.
To swap bytes received from the ASCII device, set the Byte Swap mode from
the Receive Data section of the Advance Format Configuration Category. See
Advance Format Configuration Category on page
Maximum Number of Receive Characters Parameter Rules for Usage
•
Swap Bytes Mode is set for transmit and receive independently.
•
The byte swapping works best if the max RX and TX lengths are
multiples of the byte-swap size.
Rockwell Automation Publication 1734-UM009C-EN-P - August 2022
), Instance 9, Attribute 1.
hex
), Instance 10, Attribute 1.
hex
, Instance 21, Attribute 1), the ASCII module
hex
20.
, Instance 11, Attribute 1), the ASCII module
hex
20.
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