Relay Ladder; Structured Text; Rockwell Automation Publication 1756-Rm003N-En-P - October - Allen-Bradley Logix5000 Reference Manual

Chapter 17 ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT)
Arithmetic Status Flags:
Fault Conditions:
Condition
Prescan
Rung-condition-in is false
Rung-condition-in is true
EnableIn is set
Instruction execution
Postscan
S:FS
584
Not affected
None
Execution:
Relay Ladder Action
The rung-condition-out is set to false.
The rung-condition-out is set to false.
The instruction executes.
The rung-condition-out is set to true.
N/A
The instruction clears the specified instructions and buffer(s).
The rung-condition-out is set to false.
Example:
When the controller enters Run mode, clear the buffer and the ASCII queue.

Relay Ladder

Structured Text

osri_1.InputBit := S:FS;
OSRI(osri_1);
IF (osri_1.OutputBit) THEN
ACL(0,0,1);
END_IF;

Rockwell Automation Publication 1756-RM003N-EN-P - October 2011

Structured Text Action
No action taken.
N/A
N/A
EnableIn is always set.
The instruction executes.
No action taken.
ACL
ASCII Clear Buffer
Channel
Clear Serial Port Read
Clear Serial Port Write
0
1
1