Logix5000 Controllers General Instructions - SLAC Confluence

ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT) 577Execution:Condition Relay Ladder Action Structured Text Actionprescan The rung-condition-out is set to false. No action taken.rung-condition-in is false The rung-condition-out is set to false. narung-condition-in is true The instruction executes when rung-condition-intoggles from cleared to set.naThe rung-condition-out is set to true.EnableIn is set na EnableIn is always set.instruction executionThe instruction counts the characters in the buffer.The .EN bit is set.The remaining status bits, except .UL, are cleared.The instruction executes.The instruction attempts to enter the ASCII queue.postscan The rung-condition-out is set to false. No action taken.Example:Continuously test the buffer for the termination characters.Relay LadderMV_line.EN/ABLASCII Test For Buffer LineChannel 0SerialPort Control MV_lineCharacter Count 0ENDNERStructured TextABL(0,MV_line);Publication 1756-RM003I-EN-P - January 2007