Conditional Motor Speed

Hello men

Using RSLogix 5000 Software

I am having a problem trying to figure out how to properly program the speed of a motor using a VFD with the conditions of discrete outputs. I know I know very easy stuff to you all but I am having problems.

For example:

I have a VFD controling a feed belt. This VFD controls how much sand is on the conveyor. The sand dumps into four different silos via a distributor with four solenoid gate valves controlling which silo we want sand to fall into. Easy enough.

If all four silos are >90% capacity, the feed belt motor can run at max speed (60HZ). If 1 of the 4 silos is <90% capacity, the solenoid gate valve closes for that particular silo and the VFD needs to decrease the speed to (55HZ) which results in less material on the belt so the distributor can handle the amount of material falling into it without the extra gate valve open.

If 2 of 4 silos are <90% capacity...the same thing but it slows down a little more (50HZ) to accomidate the for only two OPEN gate valves.

If 3 of 4 silos <90% capacity...(45HZ)

If 4 of 4 silos <90% capacity...(OHZ) (I got this part...easy)

And lets say...

If 3 of 4 silos "were" <90% full but one of the three was emptied during the process, the feed motor can bump up back up to (50HZ) and so on...

Can anyone at least give me some ideas. I do not expect anyone to write it for me but I just need to some advice on how to figure this thing out. I have tried a few different test programs but no cigar.

Thanks for the help!!!

Kandy

Here is what I have tried thus far

My math functions are not addding up

It should be self explanatory

In Main_Routine:

After rung 3 add a rung - CLR Valve_Count

Remove the LES comparison rungs.

Remove the ONS commands from the GRT rungs.

bernie_carlton said:

In Main_Routine:

After rung 3 add a rung - CLR Valve_Count

Remove the LES comparison rungs.

Remove the ONS commands from the GRT rungs.

Click to expand...

Thanks Berni

That worked except for one thing.

In the VFD_Speed_Control sub routine, the instructions are not writing the value of the condition of the silos to the VFD_Speed tag.

EX:
If all four silos are >90%, the value "60" should be MOVED to the VFD_Speed tag. correct?

Any thoughts why this is'nt happening?

I updated the the project here:

you´re not calling the subroutine

Please use this file:

Not the one above

widelto said:

you´re not calling the subroutine

Click to expand...

How am I not?

Please explain

Same thing.
You have to use the JSR Instruction.
See attached fig.

Ha nevermind

I got this thing figured out now

Thanks Berni

I thought I needed one shots for adding and less than instructions.

Thanks again!

Here's the final test result.

I just kept it all in the main routine