Allen-Bradley Logix5000 Reference Manual page 576

Chapter 17 ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT)
576
Scan
Rung-condition-in false
.EN off
.EU off
.RN off
.DN or .ER off
.FD off
.EM off
Enters Queue
Executes
In this example,
finds termination
characters.
The ASCII queue holds up to 16 instructions. When the queue is full, an
instruction tries to enter the queue on each subsequent scan of the instruction, as
depicted below.
Scan
Rung-condition-in false
.EN off
.EU off
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Scan
true false
on off
on
on off
on
on
on
When scanned and .DN
or .ER are set, sets the
.EM bit.
Scan
true false
on
Attempts to enter queue but queue is full
Scan Scan
true false
on off
on off
off on
off on
off on
Resets status bits.
Scan Scan
on
Enters queue