Automating Manufacturing Systems - Process Control and ...

plc function ref - 34.37
34.1.12 String
ABL, ACB - Ascii availaBle Line, Ascii Characters in Buffer
A
ABL
ASCII TEST FOR LINE
Channel 0
Control R6:0
Characters
Description:
Status Bits:
The ABL instruction checks for available characters in the input buffer.
In this example, when ’A’ goes true the function will check the input
buffer for channel ’0’ and put characters in ’R6:0.POS’. The count
will include end of line characters such as ’CR’ and ’LF’.
The ACB instruction is the same, except that it does not include the end
of line characters.
none
Registers: POS the number of characters waiting in the buffer.
Available on: Micrologix, PLC-5