tank level

Have a question. Have a project where I will be taking about 6 chemical storage tanks and creating a control system to be able to monitor the level in gallons and display on a screen.
Looking at using a micrologix 1200 or 1100 and a panelview display.

Not sure exact dimensions of tanks yet, ( they are in Honduras), but have been told they hold 1000 gallons each.

I am looking at using a ultrasonic sensor with a 4-20ma output.
It appears that it would just be a matter of using the SCP instruction, where the input min would be 0 and the input max would be the raw value of the ultrasonic sensor at 20ma, and the scaled min would be 0 gallons and the scaled max would be 1000 gallons.

I contacted my ab rep and he sent me following pdf file on a ultrasonic sensor that they sell, was wondering if anyone has used any of these on a similar project, or would be willing to share how they may have done something similar.

Thanks for any input.

Yo HoundDog,

Here is a proposal for a project that I am working where we will be doing the same thing. Only on this project we will be using a pressure transmitter from TURCK to measure the volume in the tanks. We will then be taking those 4-20mA signals from the tanks into wireless nodes from Banner and then the values will be read back at the control room and displayed on webpages via RedLion's DataStation Plus product. Well heck, here is the preliminary proposal.

Tank Monitoring

Joe_WaZoo

Thanks

Great document, always found your post to be good.

At the moment, due to budget constraints, the wireless will most likely be out of the picture.

Will call my banner rep and see about the pressure transmitter.
How are you mounting it?

At the moment, looking at using a micrologix 1200 and a panelview micro 300 that will be mounted in enclosure at the tanks.
They are all close together, in one corner of the bulding.

An ultrasonic unit
- needs top access, at some distance from the side wall to prevent echoes off the side wall. Is top access already available? Is the fitting access big enough?
- sufficient empty space below the transducer to allow for blanking zone where no return echo can be read (typically 12" or 300mm).
- should have some means of adjusting for atmospheres other than air, because many chemicals have sufficient vapor pressure to create a vapor blanket which will not conduct sound at the same speed as air (N2/O2 mixture) will.
- should be temperature compensated, but most are nowadays.
- cannot deal with foam
- materials of construction need to be withstand and be compatible with chemicals
- needs signal processing if there are internal ladders, struts, mixers, agitators, bin walls, or obstructions in order to eliminate false echoes.
- generally can't shoot through a CO2 blanket. Nitrogen blanket is OK.

Dan

HoundDog,

That is a good question about how we are mounting the transmitter. I believe that the application has a tube out of the bottom of these tanks that we can thread the transmitter directly into it. Here is a link to the pressure transmitters we will be using from TURCK: When I get finished with this project I will post the pictures of how we did the mounting.

TURCK Pressure Transmitter

Ask your Banner guy about the wireless costs. I think you will be amazed at the costs, it's much less than you would think. What state do you live in?

The RedLion HMI screens could read those values in, do the scaling, and display them on the screen in one unit. You would have to either use their I/O or someone else I/O to convert from analog current to say Modbus registers. If I wasn't doing the wireless on my tanks application, I would use the BL20 I/O from TURCK to read in my values on ModbusTCP.

Thanks,
Joe_WaZoo

Joe,

Can we please keep the infomercial down to a dull roar.

Nick

Nick,

No problem, just thought I would share how one person is solving this type of application.

Thanks,
Joe_WaZoo

Nick B said:

Can we please keep the infomercial down to a dull roar.

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Personally, I like hearing about the brands of products that people are using. If you watch this site for awhile, you start to see that certain people push certain brands in many of their posts, but so what? I'm glad they found something that works for them.

I really don't see how we could have a productive discussion here while avoiding brand names. Speaking of Red Lion, the president of the company and several others like Dan Yost probably wouldn't have joined this forum if people weren't discussing their products. Frankly I'd like to see more of that. Anybody here from Rockwell? Sigh... didn't think so.

kolyur said:

Anybody here from Rockwell? Sigh... didn't think so.

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Comments like this slandering manufacturers without grounds are exactly why more manufacturers don't participate. Kolyur, you seem to be terribly misinformed. Rockwell is here and are extremely helpful, even to those who make false accusations such as this. In fact as I search through your threads, I see you have even received assistance from Rockwell here.

Look we all work for somebody...our customers or are company. I would suggest that if you looked over my posts you would see a pattern of the kinds of questions I participate in. From there you could extrapolate whom or the type of business I'm involved in but never have I offered up a pitch to move or promote product.

I'm simply implying that it was a little over the line and I think Joe knows this, c/w Power Point.

Nick

TWControls said:

Rockwell is here and are extremely helpful, even to those who make false accusations such as this.

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I was not at all implying that I have not received help for Rockwell products at this site. I'm sure if you looked at my posts you will see that most of them are Allen-Bradley related. And I'm sure that a number of forum members here are employed by Rockwell or their distributors, and have provided a lot of help to a lot of people (including myself).

My point is simply that Rockwell is not officially involved in this forum. With Red Lion, for example, I can call their tech support line and speak to the *same* people who are posting on this site. That is a real benefit in my mind.

I understand that Rockwell's size or organization may prevent that kind of involvement and that's OK. I wasn't trying to slam Rockwell and I'm sorry if that's how it came across.

-John

Anyway.....

We have quite a few of these bad-Larrys around Flowline LU30 they are pretty easy to setup, just have to watch the deadband, I believe it's 6" from the sensor. As-stated previously you need top access and you may need to set it up to counter-act foam (insert a pipe into the tank, have the sensor shoot down it), but pretty stout especially in our environment. We have H2SO4, HCl, NaOH....bunch of other good stuff too

The Turck is a gauge prssure sensor.

To use a gauge pressure transmitter the tanks MUST be open top or open vented to the atmosphere. By open vent to atmosphere, that means an opening that you can stick a rod through, with no obstruction.

It pays to check this out thoroughly, because I've had people tell me that their tanks were vented to atmosphere, when in fact, the tank regulating vents. In one case each tank had a weight loaded vent that allowed up to 0.25psig pressure build-up before the vent released. It also prevented inlet air from coming in until the pressure inside the tank dropped below 0.25psig below atmosphere.

What happened when a gauge pressure transmitter was installed was
- the tanks inidcated overshoot on filling
- undershott on emptying
- the high vapor pressure chemicals produced levels that oscillatied with the tank temperature. The tanks were essentailly giant thermometers; a closed system with vapor pressure rising and falling with temperature.

I learned to be very, very specific about exactly how closed tanks are vented, because all vents eventually vent to atmosphere, even if through a catalytic incinerator, but some
goes onto a weight loaded tank. So someone answering whether his tank is vented to atmosphere can honestly answer yes, even if it is not an open vent.

Differential (P) pressure transmitter eleiminate the problem of closed vents, but require the overhead vent pressure be plumbed ot the 2nd "low" pressure port on the DP transmitter.

Dan

Thanks for the advice.

Never actually attempted this tank measurement before, so hearing about others experience and what product they actually used is very helpful.

If someone has a issue about someone telling which product they may have used, then maybe they should not participate, or just go somewhere else to complain.

Keep up the the great replys to folks who post seeking advice from others who may have already experienced what we may be wanting to try.
As for me, with the budget constraints now, actually hearing how a certain product worked is very useful.

I have successfully completed quite a few projects using advice from folks such as TW and Joe

Thanks

Joe
I hope you post the results. Will be looking for it

Thanks

Joe_WaZoo said:

HoundDog,

That is a good question about how we are mounting the transmitter. I believe that the application has a tube out of the bottom of these tanks that we can thread the transmitter directly into it. Here is a link to the pressure transmitters we will be using from TURCK: When I get finished with this project I will post the pictures of how we did the mounting.

TURCK Pressure Transmitter

Ask your Banner guy about the wireless costs. I think you will be amazed at the costs, it's much less than you would think. What state do you live in?

The RedLion HMI screens could read those values in, do the scaling, and display them on the screen in one unit. You would have to either use their I/O or someone else I/O to convert from analog current to say Modbus registers. If I wasn't doing the wireless on my tanks application, I would use the BL20 I/O from TURCK to read in my values on ModbusTCP.

Thanks,
Joe_WaZoo

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