Multi speed motor logic that is understandable.

I will probably NOT be starting a machine up on site. So I am trying to make my code where the start up guy can read and hopefully understand it.

I have a filling system with 3 nozzles. Each nozzle of the 3 has 3 positions. Full open, half open, closed. That makes 28 possible combinations.

The drive I am using is an 8 speed. It has 3 inputs that make up the speed changes.

Does anyone have a clean looking way to make this? Everything I have came up with looks ugly and requires an excel spreadsheet to make since of what I am doing.

I guess you have different combinations of speeds for how many nozzles are open (and to what rate)
can we see that matrix ?(excel should be ok)
Also what PLC platform are you on

If I understand correctly, you're trying to match the motor speed to the number of nozzles and their opening.

Are all three nozzles identical? If so you have ten different possibilities:
1. All three nozzles closed
2. One nozzle half open
3. Two nozzles half open
4. Three nozzles half open
5. One nozzle full open
6. Two nozzles full open
7. Three nozzles full open
8. One nozzle half open, one nozzle full open, third nozzle closed
9. Two nozzles half open, one nozzle full open
10. One nozzle half open, two nozzles full open

Assign a numeric value to each valve state, say zero for closed, 1 for half open, 4 for full open. Each of the ten possible conditions results in a different numeric value.

State 1 = 0
State 2 = 1
State 3 = 2
State 4 = 3
State 5 = 4
State 6 = 8
State 7 = 12
State 8 = 5
State 9 = 6
State 10 = 9

The three inputs to the drive will correspond to a number between zero and seven, so you'll have to have some of the different states have the same speed unless you can use a drive with four inputs designated for preselected speeds.

Is analog possible?

Sorry for the delay guys I have been working on this job. Yes you are both correct in the assumption that I want to vary the flow according to the opened valves.
MichaelG, Steve did the basic breakdown for my system. It is on a ControlLogix

OK Steve I thought (dangerous word) that it would be 3^3 not 3*3.
I like the basic idea of where you are going with this. I did almost the exact same thing except I was 28 possible combos instead of 9. I could probably deal with 9 different patters easily. I was thinking of 0 (off), 1 (half), 2(full) just using 2 bits. I am going to try to sleep on it and see what hits me.

Thanks for the help.

No the tightwad I am working for didn't see the need for communications or analog. Just use step speeds it is cheaper anyway.

Somthing like this uses 6 speeds just put a 1 in the open and half cells for max output for that valve or 1 in half cell or 0.......

JeffKiper said:

OK Steve I thought (dangerous word) that it would be 3^3 not 3*3.

Click to expand...

Actually, it would be 2^3=8 including all three bits being zeros.
All zeros may not be too useful depending on the situation, but that gives you 7 possible speeds for sure.

If you had 4 bits to use for speed selection, it would be 2^4=16, and so on.

Stu....

Did the tightwad give you another output for Drive run?
If so there is your all closed speed (drive stopped)
Now you have 8 presets for 9 states
I would use Steve Bailey method
Create an array index based on the valve states 0 closed 1 half 4 Open
Value in the index is the Speed reference that you want to use 0-7
Map the bits to the digital
The Guy on site can adjust the drive speeds and can fiddle the value in the index to suit

PS most (Cheap) drives only have 8 Presets

Example program Logix V19.01 doing this