RSLogix 500 Program Review & Advice Needed

[iadapt]

Lancie1 yes I need to go right to the spray timer, sorry on the road right now.

 

[Lancie1]

Understanding the problem is always 90% of the battle. I now think the fix is simple.

Inserting a new rung 1 to the Tank 31 routine, with the MOV timer T4:0.PRE to T4:0.ACC seems to work to cut the Valve Close cycle short and goes directly to the Valve Open step, as shown in the attached R1 version of the LogixPro program.

You would need to add a similar rung for Tanks 32 and 33.

 

[iadapt]

Hello Lancie1 and Bit_Bucket_07 and the_msp. I am looking at the suggestions you have all made now. I cannot thank you enough for all the help. I will work hard to give back to the community. Thanks.

 

[iadapt]

It seems to work really well. So I have never personally used a MOV of PRE & ACC and I cannot see the instruction working. I just see that it works as I need it to. I understand what a MOV instruction does and a OSR does I just haven't used them like this. So the OSR gives a one shot I get that I get the MOV I just cant see any of it in the Data Table. Where can I observe this so I can clearly observe it for future use. I dont just want to use it I want to own it. Thanks everyone for your help.

 

[Lancie1]

To see anything happening, you would have to watch T4:0.ACC. When I:1/0 goes on, the value of T4:0.ACC should immediately jump to "20" seconds (or whatever T4:0.PRE is set), causing the timer to go DONE and start the Valve Open step on rung 002. If you want to "see" it, temporarily change the MOV to MOV "18" to the T4:0.ACC. Then you will see the timer jump from some smaller number to 18, then continue counting to 19, then 20.

This was an effort to not change any of your existing working logic. That is always the key factor when modifying a working program. It will work for you if when I:1/0 goes ON, you want the valve to immediately open, and the Soak Timer to start (which then starts the Spray Timer).

 

[iadapt]

What if I want the sprayer to delay until I:0/0 de-energizes? So it will have an early, on time and a delay option. How might I address that?

 

[iadapt]

Wouldn't I just treat the options like I would a selector switch. By the way the OSR option does not start the sprayer immediately it waits until the soak timer is done. Is that supposed to do that? It will begin spraying too late if that is the case.

 

[iadapt]

Im going to try to observe the data file and create an option to delay the sprayers until I:0/0 is lifted.

 

[iadapt]

Ok I got it! Its not exactly what I need, but I got what your doing. Kool! Still working on it.

 

[iadapt]

I GOT it!! I just added a EIO instruction before T4:3 to delay until the limit switch is lifted and you guys provided the MOV instruction if it goes early. So cool, to solve it.. Thanks...

 

[Lancie1]

What if I want the sprayer to delay until I:0/0 de-energizes? So it will have an early, on time and a delay option. How might I address that?

Before we go down this path too far, please answer this:

How can the PLC tell the difference between a regular old cycle where I:0/0 goes on and the valve opens and the soak timer runs and the spray timer runs, and an "early" cycle where I:0.0 goes ON? Is there something else that can tell us that a cycle is "early"? (If not we are screwed!)

Maybe if I:0/0 goes ON AND T4:0/EN is ON too would that say "yes, here is an early cycle". If so, then you can use I:0/0 and T4:0/EN to turn on a new "Early Spray Bit", then use that new bit to energize the spray timer (without turning on the soak timer).

If not, then what does determine an "early" cycle?

 

[iadapt]

Change that - I had to put it before the T4:1. To hold (delay) the sprayers until the limit switch was de-energized. It finally works perfect.!! Just wanted to update you guys and let you know the end result. Thanks for the direction and help!

 

[iadapt]

Lancie1 not there is not anything that identifies en early, regular or late time. It does seem to work I just changed the timer to T4:3 with the Pre and ACC. Next I had to put an EIO instruction on the rung with the open valve. I can let the delay timer run as long as I want until I de-energize the I:0/0. Then the open valve energizes and completes the cycle. Does that seem right to you?