Logix5000 Controllers General Instructions - SLAC Confluence

ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT) 591ASCII Read Line (ARL)Operands:The ARL instruction removes specified characters from the buffer andstores them in the Destination.Relay LadderARLASCII Read LineChannel ?Destination ???SerialPort Control ?SerialPort Control Length ?Characters Read ?ENDNEROperand Type Format Enter NotesChannel DINT immediate 0DestinationSerial PortControlSerial PortControl LengthstringSINTINTDINTSERIAL_PORT_CONTROLtagtagtagtag into which thecharacters are moved(read):• For a string data type,enter the name of thetag.• For a SINT, INT, or DINTarray, enter the firstelement of the array.tag that controls theoperationDINT immediate maximum number ofcharacters to read if notermination characters arefound• If you want to compare, convert, ormanipulate the characters, use a string datatype.• String data types are:• default STRING data type• any new string data type that you create• Enter the maximum number of charactersthat any message will contain (that is, whento stop reading if no termination charactersare found).For example, if messages range from 3 to 6characters in length, enter 6.• The Serial Port Control Length must be lessthan or equal to the size of the Destination.• If you want to set the Serial Port ControlLength equal to the size of the Destination,enter 0.Characters Read DINT immediate 0 During execution, displays the number ofcharacters that were read.Structured TextARL(Channel,Destination,SerialPortControl);The operands are the same as those for the relay ladderARL instruction. However, you specify the Serial Port Control Lengthand the Characters Read values by accessing the .LEN and .POSPublication 1756-RM003I-EN-P - January 2007