Alternate Pumps with Zen

Hello all, I'm looking for a push in the right direction with this one.

I'm in need to alternate two pumps using an Omron 10C3AR-A-V2 Zen program.

Here is the setup--

Float switch 2 - on - no operation
Float switch 3 - on - pump starts
Float switch 3 - off - continue pumping
Float switch 2 - off - stop pump

Which I have working great, but I cannot ,for the life of me, figure out how to get the other pump to run on the next cycle.

Any help is greatly appreciated.

welcome to the site
use the logic to control an auxilary relay
then set up a counter - preset to 1
if counter is not = to 1 use pump 1
when pump 1 is told to stop increase count
then when count = 1
call pump 2
and reset counter when pumt 2 stop is given

Which I have working great, but I cannot ,for the life of me, figure out how to get the other pump to run on the next cycle.

Click to expand...

As Ian said, you can use a counter to record that the first pump has run, so do not run it again until the second pump has its turn.

This is called alternating the pumps, often done to achieve even wear. There are several ways to create an alternator, including using a counter, one-shot bits, set and reset bits, and so on. If you search for "flip-flop" you will find many of these in old posts on this site.

Your ZEN is limited because you can only have one output per rung (no parallel outputs), and only 3 input-type instructions per rung. You can do a parallel input branch as long as you do not use more than 3 instructions. The ZEN has no built-in One-Shot (pulse) bits, so if you need that you have to create your own from normal relay-type outputs.

Luckily, there are ZEN outputs that have the Alternator Function built in for the Q, M, and Y-type outputs! The Q, M, or Y outputs can be the normal relay type ([), Set, Reset, or Alternate. Use a M-type internal relay bit for your Alternator, and use the M ON state to control Pump 1 (along with float swithces in series) and use the M OFF state to control Pump 2. For more information, see your ZEN online Help file.

I am getting closer, but still no success. Each change I make brings about some other change.

Posting what I have written.

Take a look, if you would. I know the second pump isn't in the program right now to alternate, just at the high float operation.

glplc_007 said:

Hello all, I'm looking for a push in the right direction with this one.

I'm in need to alternate two pumps using an Omron 10C3AR-A-V2 Zen program.

Here is the setup--

Float switch 2 - on - no operation
Float switch 3 - on - pump starts
Float switch 3 - off - continue pumping
Float switch 2 - off - stop pump

Which I have working great, but I cannot ,for the life of me, figure out how to get the other pump to run on the next cycle.

Any help is greatly appreciated.

Click to expand...

Sounds to me like you need a binary toggle.....

For the limited ZEN, try something similar to this. The M0 internal relay should be set to the built-in "Alternate" function. You are limited to 3 horizontal instructions per rung. You do not need to invent new float switches for each rung - you only have TWO physical float switches FS2 and FS3, so you must get by with those. In any PLC program, you are allowed to reuse input instruction addresses as many times as you need them.

That was the trick I was after!!
Thank you Lancie1

Dear,
i am looking for LD program using logo plc 0BA6 220ac to run two pumps alternately , the only in put is a pressure switch
pump-1 start when main switch on
when pressure switch is high pump-1 stop
when again pressure switch low Pump-2 start
on high pressure pump -2 stop
on low pressure pump-1 start again
best regards

You might want to expand out the duty switch logic to accommodate pump not available issues ( assuming you have overloads as io etc)... Don't want to swap duty to a broken pump...