Sump Pump controller program

Hello all,

I am very new to plc programming and have been watching videos, and reading up on them. I have a beginners class Mid March.

I have a Micrologix 1500 controller that I am using RSlogix 500 to tinker with on my desk. I can connect to the PLC go online and manipulate the program.

This will be a real world project.

Controlling sump pumps in our sump drain.

The normally open float switch will determine how long the pump runs, water rises in the pit the float switch closes and the pump comes on, water level falls the switch opens and pump shuts off.

I want to be able to turn on another output to a solenoid valve when the float switch closes to turn the pump on for a specified amount of time. then shut off even though the float switch is still closed running the pump.

Water rises>float switch closes> this is connected to an input on plc > this starts a timer as well that runs for 1 min > turns on an output> timer times out> turns off that output> pit is not drained so pump is still running till water falls in pit to open float switch and shut off pump> starts all over again when water rises.

I am currently doing this with a mechanical timer, I figured this would be a good real world project to learn on and not interfere with production machines.

I already have a TOF timer controlling an output in the small program I have written so far, this works as I need it to, it will do something else associated with the sump pump process.

We have self priming sump pumps and they sometimes lose their prime. The output will control a solenoid that comes on when the pump starts to open the water valve to prime the pump each time the cycle starts.

The TOF timer will run after the pump shuts off to wash a screen that we screen the sump water with.

We make color concentrate and screen and filter our sump discharge before pumping into the sanitary sewer.

I searched the forum and see some sump pump projects. If this is in there I did not see it.

Thanks for making it this far.

Scott

-----I I-------------TON--------

----I I------I/I---------SOL----

where each XIC is the input fed from your float switch and the XIO is the timer.DN bit, you know the rest...

May want to use an interposing relay between the PLC output and the Solenoid

Regards

Thank you Sir, worked like a charm. Elementary for you,

Terminology clarification, what do you mean by interposing relay? A relay between the output and the actual solenoid?

Scott

You're very welcome, and yes;

Lots of info available on interposing relays used especially when the PLC output is a solid state device.

Regards

Sherlock4me said:

interposing relays are usually a good idea for solenoids and other inductive loads, especially if the PLC output is a solid state device as opposed to a relay output.

Click to expand...

I did one project using a DirectLogic DL-240 with relay outputs & got called back more than once due to blown fuses on the PLC output cards. First I added a bank of interposing relays for all 9 of the solenoids, but then got called back again. That time I added another bank of relays for all the contactors the PLC was controlling (and these weren't large contactors either) & haven't had a problem since - so now I always use ice-cube relays to control ALL solenoids & contactors larger than a general purpose relay.

Yes, I have seen similar situations Aabeck, I deleted "inductive loads" before I was rightly "corrected" since a relay is also an inductive load, decided that was better than my giving a boring tutorial on coil sizes.. and as you say even with PLC relay outputs it can be the wise choice... : )

Thanks again, I was envisioning an ice cube type relay, Igoogled this and see how it works and applies.

Scott

Thanks for all the help so far. I have another question about which PLC to use. I think the ML 1500 is a bit of an over kill for what I am doing. I'll attach my .rss here and see if it will run in a ML1000 or something along those lines. I picked the ML1500 1764 lrp c because it matches 3 others I have in the facility I am in. I also placed it in a 1764-24awa b 24 point controller. I am only currently using 2 of the inputs and 2 of the outputs. I have about $1500.00 in this setup If I remember correctly. No need in tying up that much money if less will do. I might as well stick with AB as that is what we have from the get go.

I figured I would throw this out to the fine group here for comments.

Thanks all.

Scott

Hello,

I just read through your post quickly, so excuse me if I have your intention wrong here.

It sounds like you just want to turn on a sump pump when float is high (closed) and at the same time you start the pump you want to open a solenoid valve to prime this pump.
Then you want the solenoid to go off after a set time period.
And the pump to go off when the float is low again (open).

If my assumption is correct then you can accomplish this with only 2 rungs.

See below:

And here is the same logic with a Off Delay Timer added to keep the sump pump running a bit longer after the float has opened.

Not sure if you wanted this or not, but it is often the way sump pump logic is written, as the sump pump usually sits much lower than the float.

This way you can pump out max amout of water from sump.

I used 10 second presets on both timers but you can set them where ever you like.

(Also you dont really need an expensive PLC to do this simple logic. You could use PICO, LOGO, or other similar brand, and do this for just over $100)

I like AB micrologix but I am doing 10 sump pump panels right now all with Siemens LOGO. My code is much more complex than what you are using and LOGO works well for very cheap.

BCS

Thanks BCS,

I know when learning something new there are more ways to drain the sump or skin the cat. I have 2 pumps in this currently. They will both do the same thing so I put the two inputs around like I did so the solenoids would operate the same no matter which pump came on, or if both of them are running at the same time. I will be operating 2 solenoids here 1 is to prime the pump, either pump. and the other will be to run a solenoid to turn on to wash the screen as the pump is running. the delay off will give it a bit of wash after the pump shuts off. At the same time the pump is running another solenoid will be on to stir the sediment up in the sump while the pump is running, this will suspend it in the water while the pump is running to pick up the suspension and run it over the screen. There by eliminating the hazard of someone having to drain the sump and manually cleaning it out from time to time.

I know this can be done without a PLC, however it is a real world test instead of just turning lights on and off on my desk here.

Many thanks for your taking time to post the pictures of the code. I appreciate it.

On a side note my oldest Stepson spent a season going across the sound from Cordova to Whittier on a boat to haul semi trailers across there. He had a good time.

Scott

Ok, I guess I just dont see all that in the ladder that you posted.

Anyway here is another picture just for your reference, this one I use the Off Delay timer to keep the wash solenoid I added sealed in after the pump shuts off.

You will be using relays for you motor and solenoids anyway so your agitator solenoid can come off of the same ouput as motor run.
(or you can add another OTE on a branch extension under the motor run output if you like.)

If you are using 2 pumps then you just need to add the logic for the second pump to work how you want it to.

Good Luck

BCS

Thank you.

Scott

I am only currently using 2 of the inputs and 2 of the outputs. I have about $1500.00 in this setup If I remember correctly. No need in tying up that much money if less will do. I might as well stick with AB as that is what we have from the get go.

Click to expand...

For 2 digital Inputs and 2 Outputs, you could use one of the programmable smart relays (stripped-down PLCs) that still have programming software, such as the Eaton EZ-Soft, the AB-Moeller Picosoft, or the Omron Zen. The price would be more like $200 instead of $1500.

Thanks Lancie

Scott