ML1500, Delaying Run Mode

[Thomas Franklin]

Does anyone know if there is a way to delay a ML1500 from going into run mode throu programming.

Thomas

[leitmotif]

Why would you want to delay the PLC from going into run?

Need to learn something new today.

Dan Bentler

[TConnolly]

Originally Posted by Thomas Franklin

Does anyone know if there is a way to delay a ML1500 from going into run mode throu programming.

Thomas

There is no way to programatically delay the processor from going to run mode, however there is a way to accomplish what you want to do: Use subroutines.

In ladder two, program only a timer and a call to the subroutine conditioned to execute when the timer completes. Place the rest of the program in subroutines.

The following will wait for ten seconds after the processor goes to run. During that 10 seconds, it will unconditonally turn off the outputs on the fixed IO base (in case any were latched on when the program halted). After ten seconds it will execute subroutine 3 continuously.

TON T4:0 1.0 10 0
XIO T4:0/DN CLR O:0.0
XIC T4:0/DN JSR 3

You may wish to divide up your program into parts that need to be delayed and parts that do not - such as an initialization routine - as well as logical parts by function.

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edit
Another way to do this is with a JMP. The first two rungs of the program would look like this:

LBL 1 TON T4:0 1.0 0 0
XIO T4:0/DN BST CLR O:0.0 NXB JMP 1 BND

I recommend the subroutine approach however.

[TConnolly]

Originally Posted by leitmotif

Why would you want to delay the PLC from going into run?

Need to learn something new today.

Dan Bentler

I imagine he needs to wait for something else to start up but doesn't want to program a time delay for every single output.

[bernie_carlton]

I think this ties into his previous post of the CPU falting on going into run because of an I/O module. He thinks that delaying the transfer to run will avoid this.

[leitmotif]

Originally Posted by bernie_carlton

I think this ties into his previous post of the CPU falting on going into run because of an I/O module. He thinks that delaying the transfer to run will avoid this.

Bernie
Is this similar to treating gangrene by putting a band aid on it?

Dan Bentler

[TConnolly]

In that case it won't solve the problem.

Bite the bullet, get systematic and find the problem. Create a series of very simple programs each with first no expansion IO, then add the first, then add the second, etc. Starting on the left, disconnect the module, hook up the endplate, download the right modified program and test it. Repeat until you find the module. Sometimes troubleshooting is just systematically eliminating pieces one by one. When you find it, Bite the bullet again, and replace the defective hardware.

[Thomas Franklin]

Thanks for the adice gentlemen, Bernie_Carlton was right I am trying to find a back door into solving my power up fualt...I have a couple of ideas that I am gonna try and if they don't work...I will use Alaric suggestion...Thanks

Thomas

[rsdoran]

Personally I dont understand why you dont determine what the problem is, the manual http://literature.rockwellautomation...m001_-en-p.pdf

and programming set reference http://literature.rockwellautomation...m001_-en-p.pdf
explain how to troubleshoot errors etc. Appendix C the user manual gives troubleshooting help, Appendix C in the reference manual explains the status bits.

If the problem is in the program then it may start "faulting" while running under certain conditions or situations.