Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 583
ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT) Chapter 17
ASCII Clear Buffer (ACL)
The ACL instruction immediately clears the buffer and ASCII queue.
Operands:
Relay Ladder
Structured Text
The operands are the same as those for the relay ladder ACL instruction.
Description: 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:
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.
Operand Type Format Enter
Channel DINT Immediate
Tag
0
Clear Serial
Port Read
BOOL Immediate
Tag
To empty the buffer and remove ARD and ARL
instructions from the queue, enter Yes.
Clear Serial
Port Write
BOOL Immediate
Tag
To remove AWA and AWT instructions from the
queue, enter Yes.
ASCII Clear Buffer
Channel ?
Clear Serial Port Read ?
Clear Serial Port Write ?
ACL
ACL(Channel,
ClearSerialPortRead,
ClearSerialPortWrite);
If Your Application Then
Uses ARD or ARL instructions Select User mode
Does not use ARD or ARL instructions Select either System or User mode
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