Allen-Bradley Ethernet Driver
Syntax Data Type
A<file>:<char> Char, Byte*
A<file>:<char> [rows][cols] Char, Byte*
A<file>:<char> [cols] Char, Byte*
A<file>:<word offset>/length String**
Note: The number of array elements cannot exceed the block request size specified. For more information,
refer to Block Request Size.
*The PLC packs two characters per word in the file, with the high byte containing the first character and the low
byte containing the second character. The PLC programming software allows access at the word level or two-
character level. The AB Ethernet driver allows accessing to the character level. Examples are as follows:
l Using the programming software A10:0=AB would result in 'A' being stored in the high byte of A10:0 and
'B' being stored in the low byte.
l Using the AB Ethernet driver, two assignments, A10:0=A and A10:1=B, would result in the same data
being stored in the PLC memory.
**Referencing this file as string data allows access to data at word boundaries like the programming software.
The length can be up to 236 characters. If a string that is sent to the device is smaller in length than the length
specified by the address, the driver null terminates the string before sending it down to the controller.
File Numbers and Character Locations
The following file numbers and maximum character locations are allowed for each model.
PLC Model File Number Max. Character
SLC 5/05 Open 9-999 1999
PLC-5 Family 3-999 1999
SoftPLC N/A N/A
Note: All SLC 500 PLCs do not support ASCII file types. For more information, refer to the PLC doc-
umentation.
Example Description
A9:0 Character 0 (high byte of word 0)
A27:10 [80] 80-character array starting at character 10
A15:0 [4][16] 4 by 16 character array starting at character 0
A62:0/32 32-character string starting at word offset 0
String Files
To access data in a String file, specify a file number and an element. The only data type allowed is string, which
are 82-character null-terminated arrays. The driver places the null terminator based on the string length
returned by the PLC.
Syntax Data Type
ST<file>:<element> String
Note: Arrays of strings are not supported.
Tip: String length can be obtained with a COPY or MOVE function.
File Numbers and Word Locations
The following file numbers and maximum word locations are allowed for each model.
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