Water distribution control

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Jason Priebe

Hello, I am pretty new to process control and have been given the task of coming up with a control system to monitor and control water usage from a well. There are 3 users to the well and each will be given priority for every third hour. During that hour the other two cannot use the water unless the priority user is not using the well. This seems pretty straightforward to me but I reall am not sure where to start the process of looking for a controller/programming software.

Any help would be greatly appreciated.

Sincerely
Jason Priebe

B

Bob Hogg

Hello, just a start
- is this a low cost application? What do you think the flow would be in gph per user? Do you want to monitor how much each 3rd. uses in that hour or in an week for example?

So - each unit would be controlled by a auto valve opening one 3rd. per hour - but if no flow is sensed, by that 3rd. the other two valves open allowing them to use system - correct? Besides this do you want to monitor how much each 3rd. uses over what time as above?

If you don't want a timed valve - would an indicator light work - indicating if the well is in use?

Thanks Bob Hogg www.almegcontrols.com

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Mike Trombley

Jason;
The thing you have to do is way cost over availibility. Any PLC can do the job, but the question is can the end user be without the system while you wait for repair parts, and if not are they willing to purchase spares. I would use one of the more popular systems in the customers area, if there is a big AB distributer in the area go with them that way if parts are needed you can try to buy local. Bad things happen when you least want them to. Make sure you can get the customer running as fast as you can, the customer will be thankfull for your efforts. Also it's not a bad idea to design in a bypass system or a manual control.
Mike

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phillip higgins

I would have to say for service, support and "user friendly" programming the Allen-Bradley line of PLC's is where I would look. Based on over 20 years of experience working on and using AB PLC's they have done the job. Sounds like you have good application to learn and experiment with. Contact you local AB dist. and I'm sure they will help...

thanks,
Phillip Higgins
SMT-Aliant

> Jason Priebe

A

Al Pawlowski

While this application could easily be handled by a PLC, it seems like 3 single, or a single 3, channel cycle timer (like those used for sprinklers for instance) combined with 3 flow sensors (1 in each user's line) and a few relays could do the job. The timer channel would disable/close two of the user's via the third (non-disabled) user's flow sensor ie. priority
user's timer channel "on" and his flow "on" then non-priority users "disabled".

For fail safe operation, a good solution for the user control valves might be pressure differential, hydraulically activated with electric solenoid disable types such as those commonly used for tank "altitude" valve service.

*********************
>Jason Priebe wrote:
>I am pretty new to process control and have been given the task
>of coming up with a control system to monitor and control water usage
>from a well. There are 3 users to the well and each will be given
>priority for every third hour. During that hour the other two cannot
>use the water unless the priority user is not using the well. This
>seems pretty straightforward to me but I reall am not sure where to
>start the process of looking for a controller/programming software.

Al Pawlowski, PE
[email protected]
dba ALMONT Engineering
Baton Rouge, LA USA

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Jeff C

As someone who has a done a lot of work in the water and waste water industry it is my oppinion that modern PLCs are far more reliable than timers and relays and adding redundant backup systems is usually an unnecesary complication. We use both Modicon and Allen Bradley controllers and have few problems with either one. The low end PLCs such as the AB micrologix or Modicon Momentum will do more than you need and run between $500 and$1500 depending on your exact I/O. I've used many PLC systems in critical 24 hour operations such as water plants and unmanned sewr lift stations. Of course there are occasional problems but they're rare and parts availablity for major PLC manufacturers is good. You will probably want to consider a low cost HMI for status and setpoint entry. We've had great luck with the Uniop Exors ww.exor-rd.com bu the AB Panelview 300 would be another good choice.