Chapter 6 ASCII serial port instructions
118 Rockwell Automation Publication 2080-RM001D-EN-E - February 2015
ARD reads characters from the buffer and stores them in a string.
ARD operations
• ARD will be executed until all characters are received. If another ASCII
command is executed, it will be queued until ARD is finished. An ACL
on page 114 instruction can be executed in order to abort the ARD
instruction.
• Use the results of an ACB on page 111 instruction to trigger the ARD
instruction. This prevents the ARD instruction from holding up the
ASCII queue while it waits for the required number of characters.
• Status of the instruction can be extracted from the control bit of the
instruction instance (e.g. ARD_1.controlbit). This shows if the
instruction is blocking the ASCII instruction queue waiting for more
characters:
o 7th bit = Instruction is enabled.
o 6th bit = Instruction is in the queue.
o 5th bit = Instruction is done.
o 3rd bit = Instruction has an error.
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