plc notes march 16

plc notes march 16 - it is possible although not...

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Sheet1 Page 1 mcr used in pairs always 2 in the program forming a boundary the top mcr instruction needs to be controlled by an xic/xio and the bottom mcr does not need control when the mcr is true the program funfactions normally when the mcr is false 1. all inputs in the rungs between the mcr boundary willb e ignored by the plc scan 2. all ote's and ton's and tof's match fu nctons between the mcr boundaries will be de-energized no matter what the inpits do 3. all retentive output between the mcr boundaries (TRO, CTU, OLT, OTU) will remain in their last state. 4. not allowed to nest mcr's or overlap the boundaries can use unlimited number of mcr pairs. jump - label instruction -jump (JMP) is an output instruction it must be used with a label LBL instruction both require and adress 0-31 LBL instruction is the target for the jump jmp directs the plc scan to skip over tungs until a rung starting with the lbl instruction is encountered jmp should be controll by an xic lbl must be the first instruction in the destination rung
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Unformatted text preview: it is possible although not recommended to jump backwards all runs that are jumped over will have the outs reaim in their last state subroutines-by default the plc is programmed using ladder file #2 there are 1000 files available for programming filled 0 and 1 are reserved for speical programs 3-999 can be used for sub routines by fefault only program file 2 is scanned and executed by the plc if other files need to be executed, the plc needs to pause executing file 2 and stiches over execution of the called file through a subroutine instruction. within file 2, the jsr intrction is used to run subroutines jsr is an output instrctuion and should be controlled, but not required the jsr needs the routine filed # that is to be executed when the jsr instruction is true, file 2 is paused and the subroutine is executed until the end of the subroutine when it reaches the end of the subroutine file it will return to executing file 2 from where it left off...
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