Add-On Instruction Help

Using:
RSLogix 5000 V19.1

Hello

I am running into a problem that is keeping me from completing a program for a small sand plant. Here's the details of what I have done:

NOTE: This application has been simplified greatly but will still get idea accross in order to figure this little problem out.

I have four small conveyors that use the same logic. I made an Add-On instruction called: Conveyor_Control
I am executing these instructions conditionally by simple interlocking.
I have four conveyors, conveyor: A,B,C, and D.
Conveyor D turns on first
" " C turns on second
" " B turns on third
" " A turns on fourth (last)

The product (sand) falls on conveyor A, and A falls onto B, and B onto C and at last onto D which then falls into a silo.

So far in my program, this sequence works perfect. The operator must turn on each belt in sequence by using a PanelView Plus (the customer didnt want it fully automated for whatever reason). He pushes conveyor D first, C second, B third, and A last. THIS PART WORKS

If conveyor D shuts down for whatever reason, all belts in front of D must shut down simultaneously. If C shuts down, B and A must shut down also BUT D can keep moving. If B shuts down, A must turn off but D and C can keep moving. If A shuts down, B,C,D can remain on. THIS PART DOESN'T WORK

For example...

My Probelm...If I have all the conveyors running and I turn conveyor C off, C does turn off but conveyors B and A are still ON. I need the conveyors before C to turn off also. This works the same way no matter which belt I want to turn off.

My thinking was that the conditions (interlocks) before the Conveyor_Control would act on the logic of the add-on in the first rung of the add-on instruction itself, resulting in an automatic shutdown but this obviously doesn't work. If I need to elaborate on anything for further clarification, let me know.

I have also attached some sample code of this application if you all would like to check it out.
My problem lies in the "Conveyors" sub routine

PS - Please overlook the "Shutdown" paramter in the Conveyor_Control add-on. It has been deleted. I was using trial and error to fix this thing but no cigar.

Thank you guys for the help!

kandy

What looks to be happening to me is that once conveyor C turns off, the AOI that controls conveyors A and B is never called again, so the logic that would turn them off isn't being executed once C has turned off.

-Benaiah

I would just use the status of motors as a permissive for the selected motor output to be active.

So in order for conveyor A to run, the output to conveyor B must be active. In order for conveyor B to run, the output for conveyor C must be active.If conveyor B stops, conveyor A would stop due to the output for B no longer being made.

benaiahhenry said:

What looks to be happening to me is that once conveyor C turns off, the AOI that controls conveyors A and B is never called again, so the logic that would turn them off isn't being executed once C has turned off.

-Benaiah

Click to expand...

This is exactly right. The block needs to be executed all the time, and the stop bit needs to be based on the other motors running.

I totally agree with your answer here but how do I incorporate in the program? Are you saying I should modify my the logic in the subroutine or in the add-on routine?

rcflyer91 said:

I would just use the status of motors as a permissive for the selected motor output to be active.

So in order for conveyor A to run, the output to conveyor B must be active. In order for conveyor B to run, the output for conveyor C must be active.If conveyor B stops, conveyor A would stop due to the output for B no longer being made.

Click to expand...

How do I execute the block all the time with interlocks in front of it?

dskohio said:

This is exactly right. The block needs to be executed all the time, and the stop bit needs to be based on the other motors running.

Click to expand...

This what I have done BUT it doesnt work for some reason. Check out the ACD file

rcflyer91 said:

I would just use the status of motors as a permissive for the selected motor output to be active.

So in order for conveyor A to run, the output to conveyor B must be active. In order for conveyor B to run, the output for conveyor C must be active.If conveyor B stops, conveyor A would stop due to the output for B no longer being made.

Click to expand...

Right click on 'Conveyor_Control', go to 'Properties'. Select the 'Scan Modes' tab. Make a 'New' 'EnableInFalse' routine. In the generated routine place a rung with an XIC of 'EnableIn' and an OTE of 'Motor'.

I just modified the screen logic in the conveyor subroutine.

Thanks Bernie

Can you briefly explain what this does exactly?

I just simulated it and no cigar

bernie_carlton said:

Right click on 'Conveyor_Control', go to 'Properties'. Select the 'Scan Modes' tab. Make a 'New' 'EnableInFalse' routine. In the generated routine place a rung with an XIC of 'EnableIn' and an OTE of 'Motor'.

Click to expand...

The 'EnableInFalse' routine executes when the other wouldn't, because the EnableIn is false. It should be turning off the motor, which is what I thought you were struggling with.

Yes exactly. I understand its logic now. The rung does not have to be true in order for the Motor bit to be controlled. Correct? I still cant get it to work but I am getting close.

Thanks Bernie!

bernie_carlton said:

The 'EnableInFalse' routine executes when the other wouldn't, because the EnableIn is false. It should be turning off the motor, which is what I thought you were struggling with.

Click to expand...

I would pass the interlocks into the AOI as parameters.

I did a similar with grain conveyors, and had 2 interlocks in...

Upstream Running Input - USRI
Downstream Running Input - DSRI

..and two interlocks out...

Upstream Enable Output - USEO
Downstream Enable Output - DSEO

Cascading these interlocks to each other ...

USEO(1) to DSRI(2)
DSEO(1) to USRI(2) etc.

...enabled me to "model" the conveyor runs, and all conditions were handled in the AOI..

1. Cascade Start up in sequence

2. Cascade Shutdown in sequence, with run-on timers to empty the conveyors if needed.

3. Can't Start a Conveyor unless the downstream one has been running for xx seconds

4. Can't Stop a conveyor if the Upstream one is running.

5. If a conveyor trips, all the upstream stop immediately, the downstream ones can be left running, or can shutdown in sequence (options).

..and so on

My process logic just asked for a conveyor flight to run, and the interlocking in the AOI did everything else.

Once the AOI was developed and tested, using it was easy..

Thank you Daba

This works perfectly!

I learned something too. Good stuff

welcome, thanks for reporting back that you got it working !