Ascii Clear Buffer (Acl); Relay Ladder; Structured Text - Allen-Bradley Logix5000 Reference Manual

ASCII Clear Buffer (ACL)

ACL
ASCII Clear Buffer
Channel
Clear Serial Port Read
Clear Serial Port Write
ACL(Channel,
ClearSerialPortRead,
ClearSerialPortWrite);
Description:
ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT)
The ACL instruction immediately clears the buffer and ASCII queue.
Operands:

Relay Ladder

Operand
Channel
?
?
?
Clear Serial
Port Read
Clear Serial
Port Write

Structured Text

The operands are the same as those for the relay ladder ACL instruction.
The ACL instruction immediately performs one or both of the following actions:
· Clears the buffer of characters and clears the ASCII queue of
read instructions
· Clears the ASCII queue of write instructions
Follow these guidelines to program the ACL instruction.
1. Configure the serial port of the controller:
If Your Application
Uses ARD or ARL instructions
Does not use ARD or ARL instructions Select either System or User mode
2. To determine if an instruction was removed from the queue or aborted,
examine the following of the appropriate instruction.
· .ER bit is set.
· .ERROR member is 16#E.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Type Format
DINT Immediate
Tag
BOOL Immediate
Tag
BOOL Immediate
Tag
Enter
0
To empty the buffer and remove ARD and ARL
instructions from the queue, enter Yes.
To remove AWA and AWT instructions from the
queue, enter Yes.
Then
Select User mode
Chapter 17
583