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Table 13 - Transmit Data Format — Array Data Type
Byte 1
Byte 2
Next Transmit Record Number
Transmit Record Number
(Handshake Mode Only)
The ASCII module transmits a number of characters from the controller to
your serial device using:
•
I/O messages
•
Explicit messages
The character string is transmitted to your serial device when:
•
The specific number of bytes defined (Transmit Character Buffer
Length) is reached, or
•
The defined End-of-String Terminator character is detected and active.
When either of these events occur, the ASCII module stores the string data
into its internal buffer and then transmits it out its serial port.
Set Up the Transmit Character Buffer Length
The Transmit Character Buffer Length is the number of characters that the
ASCII module can receive in its transmit buffer from the controller.
Set Up and Use the Transmit Delimiter
The Transmit Delimiter is an end-of-string character that determines how
many bytes to transmit over the serial link to your ASCII device.
IMPORTANT
This Transmit Delimiter is used only if the length is 0. If this length is not
0, the ASCII module ignores the transmit delimiter and sends the defined
number of characters.
The ASCII module transmits up to and (optionally) including the delimiter
when the above condition is met. The Transmit Delimiter can be set to any
valid binary value. Be careful not to set the delimiter to a value outside of the
valid range for your data bits. A data bit size setting of 7 only allows you a
delimiter range of 0...127 dec., 00...7F
If the length is 0 and if you do not have a valid delimiter in your string, the
module sends all data characters from the I/O field to your serial device
Transmit String Data Assemblies
Transmit String Data Assemblies are the formats of the data you send from the
ASCII module – Array, Short_String, or String – to the controller. Which one
you choose depends on your application, and modifies the format of the data
field.
Byte 3
Reserved
Rockwell Automation Publication 1734-UM009C-EN-P - August 2022
.
hex
Byte 4
Byte 5-X
ASCII Data
Reserved
(max 128 bytes)
Chapter 3
Module Tag Definitions
.
Byte X+1
(Max = 132)
End of String Delimiter or
Last Data Byte
31
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