3 Pump sequencing

[NR_Locus]

Hi Everybody

I have three pumps to control in auto mode. Is it possible to do the sequencing of the three pump in hardwired without the use of a PLC. Therefore, 1-2-3-1 or 1-2, 1-3, 2-3 if one pump fail the standby starts and so on.

A solution is most welcome.

Thanks

[Lancie1]

Yes, it is possible to do the sequencing with relay logic and no PLC. It helps if you buy an Alternator Relay, which will allow your logic to select the next pump to be run (out of 2, with 1 standby).

[Lancie1]

What part of the circuit do you have done? Please post what you have, or explain how you think this problem can be solved. Have you done anything similar to this before?

I have reverse-engineered your problem and used a PLC program to simulate a relay circuit (using only relays and 3 timers). It can be done in 14 rungs, but gets a little messy for a relay circuit (23 relays needed). The timers may not be needed, depending on how you are going to determine that a pump has failed.

[NR_Locus]

No I have not done this before with three pumps. For two pumps it's easy using the flip flop relay

[Lancie1]

The problem in this case is the Standby selection based on user's choice AND when a pump fails. Once that logic is set up, the other parts fall into place, using relay logic only and 3 timers in 15 ladder rungs.

The first part I did was to set up 3 rungs that use the selected Standby Pump to then alternate between the two remaining pumps (Standby Selection and Alternator Trigger to be determined). You can see that first rung I did in the attached sample picture, Rung 009.

I then built on that by adding the rungs to select the Standby pump based on 3 manual pushbuttons. Then I added the rungs for the Alternator trigger based again on a one-shot relay output that is selected with a manual pushbutton, or when the running pump fails and goes into Standby mode (Rung 000).

This one-shot relay then tirggers the alternator logic (Rung 007), which select the pump out of the two remaining possiblities.

I will add one of the Pump Output Rung 012, to show that I have not setup and individual Start-Stop pushbuttons for each Pump (recommended).

Again, post what you have done so far, so we can build onto it.

[NR_Locus]

Hi Lancie

I really appreciate your effort but from my side I have not started anything yet and was still contemplating whether it is feasible to have the 3 pumps sequencing hardwired wired. From my side, i think it is not feasible viewing the complexity. Hence, the only option is go with a Modbus RTU.

Also, if you are verse with GE Fanuc, I attach a project where we have 4 pumps running (sequencing) with variable pumping (IN LADDER.

Thanks Lancie and other supports from you is most welcome and if have a final verision of the three pumps (PLC), please post it.

[NR_Locus]

Sorry I forgot the attachment. Here it is.

Thanks

[Lancie1]

Okay, I think you must be working on a real-life problem, so here is my version of a relay-logic sequencer (no PLC) for 3 pumps with 1 standby, with the standby pump selected manaully OR by when 1 pump fails to start.

It could be done with fewer rungs with PLC logic Sequencer instructions.

[NR_Locus]

Thanks Lancie. I will check it out.

[Lancie1]

I don't think I would attempt to wire this circuit logic with relays and timers. A small PLC would be cheaper in the long run, and you could substitute One-shot instructions for the 2-rung relay one-shots.

[iant]

about 30 years ago PLC's became cheaper when you had a count of 20 relay.
now it is about 5
consider a cheap PLC with free software and Interposing relays.
search the site there are plenty suggested.

[tovin]

Originally Posted by NR_Locus

Sorry I forgot the attachment. Here it is.

Thanks

Can you give the password

[GaryS]

Here's wat you need
https://www.yaskawa.com/products/dri...ves/iqpump1000

[Dhitzfelder]

Can it be done? Yes.

However, the wiring will be complex, difficult to troubleshoot, and considering that small PLCs can be purchased for <100 dollars, uneconomical.

[Crdss]

Good friend how to program in the Onrom clp with the COMPARE and MOVE function, alternation of 3 pumps and in case of any defect the other two take turns? Grateful