[Instruction] Contents

Ladder DiagramMnemonic codeX0Y0ORGX 0 ---------------------○aY1OUTOUTY 0 ---------------------○bY 1 ---------------------○cX1Y0ORGOUTX 1 ---------------------○dY 0 ---------------------○eN times scanN+1 times scanScan Time ta b c d ea b c d eX0X1AY0Y0Y0Y1Y1A : The internal accumulator of PLC• Besides the TU/TD instructions which can detect the status change of reference operand, FBs-PLC also providesthe instructions to detect the change of node status (power flow). For details please refer the descriptions of FUN4(DIFU) and FUN5 (DIFD) instructions at chapter 7.4.2.2 OPEN and SHORT ContactThe status of OPEN and SHORT contact are fixed and can’t be changed by any ladder instructions. Those two contactsare mainly used in the places of the Ladder Diagram where fixed contact statuses are required, such as the place wherethe input of an application instruction is used to select the mode. The sample program shown below gives an example ofconfiguring an Up/Down counter (UDCTR) to an Up counter by using the SHORT contact.X0CK7.UDCTRCV : R 0CUPORG X 0LD SHORTX1U/DCLRPV :R10LD X 1FUN 7CV: R 0PV: R 104-3