Looking for help, load cell and batching control - Happy to pay

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Hi Everyone
I am not a guru to program on Arduino; I need some help with a project involving load cells...

I will try to explain what I need:

We have 4 different materials that needs batch/mix together.
The quantity are measures by weight.
On the bottom of the 4 container, I have another container where 3 load cell (6 wires)are linked in parallel.

I need, with a GUI (Webpage/Display), able to chose how many KG of each material I need mix together.

I need 4 output to control each battle fly valve on each container.

I need 1 output to control the valve on the base of the mixing container.

I also need the ability to make the batch automatic by select how many time need run before stop.

This is most of the code need do.
Final details will be discuss after.

I am open to work on any type of micro controller.

Thanks

1 Like
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ismurdegus:
We have 4 different materials that needs batch/mix together.
The quantity are measures by weight.
On the bottom of the 4 container, I have another container where 3 load cell (6 wires)are linked in parallel.

So three load cells to weigh the whole batch? Some images would be very helpful here.

As I understand it now there are five containers; four perched on top of the fifth, and the fifth on top of three load cells which of course allow to weigh the whole thing.

This is going to be key to success: the accuracy of this weighing.

I need, with a GUI (Webpage/Display), able to chose how many KG of each material I need mix together.

Both are perfectly feasible - GUI on directly linked display with either touch screen or buttons/knobs, or web page that can be operated on any browser (tablet, phone, laptop). Which one is best depends on your actual use case. The second option is the most robust, no risk of scratches on the screen and so.

I need 4 output to control each battle fly valve on each container.

Google thinks this could be a butterfly valve, and I also never heard of a "battle fly valve". Are they operated by servo, solenoid, or in another fashion? In other words: what exact type of signal do they need?
Can/should the valve be opened partly or only wholly?
The materials to be mixed are low viscosity liquids?
How accurate does the dosage have to be?

I need 1 output to control the valve on the base of the mixing container.

Again: what exact type of signal for this valve?

I also need the ability to make the batch automatic by select how many time need run before stop.

No problem there.
But don't you need to do any cleaning? Or things like replace the receptacle that the mixing container empties into before the cycle can be completed?

I am open to work on any type of micro controller.

That will be ESP8266 or ESP32, depending on the GUI requirements. Port extenders may also have to be part of the project.

Please be aware that the project may involve load cells, the vast majority of the work will go into the user interface, regardless of which type is chosen. Even more work will have to go in there if you want it to look pretty.

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1# Yes you are correct.
2# Happy with web interface. But I would like a display that only show live the reading of the weight.
3#Sorry for my typo. Each butterfly valve are controlled via 24V contactor. I will install a rele' array to control the contactors. The micro controller need control these 5/12v DC relay.

Output 1: butterfly valve material 1
Output 2: butterfly valve material 2
Output 3: butterfly valve material 3
Output 4: butterfly valve material 4
Output 5 :butterfly valve discharge weight hopper (need have a timer to be run for 3/5min allow material discharge.
Input 1: If is HI-> Batch can start / If is LOW-> Batch can't start

4# Look at 3#
5# No cleaning need.
6# I already have the load cells installed. Just need the hardware to run automatically.
I also already have an ESP32
The GUI need look nice and simple to read. Don't need be preatty
We also need a button to reset to "0" the weight hopper.

I made a pretty horrible example. See picture attached

SAMPLE.PNG
SAMPLE.PNG985×679 10.9 KB

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ismurdegus:
2# Happy with web interface. But I would like a display that only show live the reading of the weight.

That's the tricky bit of a web interface. Some kind of ajax controls are needed for this number to update, that's one of the few things I haven't done yet.

So you have the load cells working already? Any code that can read them successfully? Obviously that's something I won't be able to test here.

3#Sorry for my typo. Each butterfly valve are controlled via 24V contactor. I will install a rele' array to control the contactors. The micro controller need control these 5/12v DC relay.

Should be no problem, assuming the relays have drivers built in and are designed to work with 3.3V signals, rather than 5V signals.

One concern is still the adding of material.
Depending on the material and the construction of the whole thing there will be some delay between closing of the valve (which takes some time in itself) and the last material hitting the bottom of the container. On top of that there's the delay in reading the load cell (there's a limit to how fast it can be sampled) and the material falling into the container also momentarily increases the down force, and hence the measured weight.

So the materials first get placed into four containers, on top of the mixing container. How are they transferred into the mixer itself? Why first weighing in those four containers and not directly into the mixer?

Output 5 :butterfly valve discharge weight hopper (need have a timer to be run for 3/5min allow material discharge.
Input 1: If is HI-> Batch can start / If is LOW-> Batch can't start

I don't understand what this is supposed to do (big picture is lacking).

[qoute]The GUI need look nice and simple to read. Don't need be preatty
We also need a button to reset to "0" the weight hopper.[/quote]

Based on that picture and the live update requirement I have the feeling it's best to have a display attached to the machine itself, and a set of buttons. 7" or up will do just fine; the largest displays for use with microcontrollers that I can readily find are 10.1" 1024x600px displays.

Four push buttons for the four bins and a dial (rotary encoder) to increase/decrease the weight, set limits and increments (e.g. 0.5-20 kg limits; 0.1 kg increments). Press button to select a bin, then dial left/down and right/up.

One push button to zero the total weight (set tar weight).

There's something marked "batch instance" - what's that supposed to do?

And finally a push button to start and stop the mixing process.

What do the four large blue bars marked BIN 1 through BIN 4 stand for?

Touch screen is also an option; input of the weight would then be through an on-screen numeric keyboard. Which option is better depends on your end users.

I'm imagining an industrial or at least lab style setting for this project, am I right?

5

I have built a weighing system to fill containers of liquid that runs on a Raspberry Pi. I don't have any photos of it on my project portfolio, unfortunately.

That system uses a small touch screen (3.2"), but for your application I'd recommend a larger one since one of the things we discovered is that the smaller screen is just less convenient and it's hard to have enough area to both display all the data you want to see and enough room for big touch areas. Also, actual push buttons work a lot better for providing feedback.

If you're open to this being done on a Pi instead of an Arduino, I'd be happy to suggest some design decisions that could be taken with the project.

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@wvmarle
I have all the load cells installed already. I am using a manual system at the moment.
The weight hopper is connected to a digital scale (Rinstrum R420).
The material flow very slow. no problem for delay reading.

The 4 main hopper are 1000Kg capacity.
The final batch is 100Kg max

The reading resolution is at 1Kg

exact type of signal do they need? > no/nc contact
Can/should the valve be opened partly or only wholly? > fully ON
The materials to be mixed are low viscosity liquids? > coffee beans
How accurate does the dosage have to be? 1Kg

Before the material drop into the weight hopper is slow down via a feeding screw.

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ismurdegus:
The weight hopper is connected to a digital scale (Rinstrum R420).

Do you know how to read that thing with an Arduino or other microcontroller?

ismurdegus:
The 4 main hopper are 1000Kg capacity.
The final batch is 100Kg max

Shouldn't that be the other way around?

8

Looking at the manufacturer's web site of that scale, it seems that the load cells offer a 4-20 mA signal to the K420-K401-A display unit which then displays the weights. The K420 has an optional M4202 module for serial output, including RS485 and RS232 for communication with a computer (or Arduino). That would be the best way of getting the weights out.

Second choice is to hook into that 4-20 mA signal and read that, but you'll probably need to do some calibration to get the correct readings.

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wvmarle:
Looking at the manufacturer's web site of that scale, it seems that the load cells offer a 4-20 mA signal to the K420-K401-A display unit which then displays the weights. The K420 has an optional M4202 module for serial output, including RS485 and RS232 for communication with a computer (or Arduino). That would be the best way of getting the weights out.

Second choice is to hook into that 4-20 mA signal and read that, but you'll probably need to do some calibration to get the correct readings.

If we can use the Rinstrum scale already installe will be the best!
The scale module has rs485 and rs232 communication port that can be use.
I have the module too!!!!!

10

Excellent.The manual says there should be two RS232 ports: one for a printer, one for a computer, and one RS485 port also to connect to a computer.

To talk to an Arduino/ESP, this requires an RS232/TTL or RS485/TTL module. That's easy enough to implement, those modules can be bought ready made. The manual that I've seen seems to list out all the commands on how to communicate with the machine (I didn't read it in detail, just had a quick look). So that's all doable but takes time to develop the communications. And that's tough without having access to the actual hardware for testing. The manufacturer has some software on their web site which may be helpful in this part, again not checked it in detail.

The control logic is fairly straightforward after this communication has been established. Open valve, wait for required weight to have been dispensed, close valve, do this four times, then start the mixing process.

That leaves the user interface. Another biggie. Plus the hardware and enclosure to go with it.

11

wvmarle:
Excellent.The manual says there should be two RS232 ports: one for a printer, one for a computer, and one RS485 port also to connect to a computer.

To talk to an Arduino/ESP, this requires an RS232/TTL or RS485/TTL module. That's easy enough to implement, those modules can be bought ready made. The manual that I've seen seems to list out all the commands on how to communicate with the machine (I didn't read it in detail, just had a quick look). So that's all doable but takes time to develop the communications. And that's tough without having access to the actual hardware for testing. The manufacturer has some software on their web site which may be helpful in this part, again not checked it in detail.

The control logic is fairly straightforward after this communication has been established. Open valve, wait for required weight to have been dispensed, close valve, do this four times, then start the mixing process.

That leaves the user interface. Another biggie. Plus the hardware and enclosure to go with it.

This is great news!
I also have the rs232/TTL module.

At home I have anothert R420 and I also have a dummy load control that can be use to test the scale.
I have the manual from the scale and the software to edit the setting menu.

What is next step?

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What setting menu? Part of the scale controller?

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wvmarle:
What setting menu? Part of the scale controller?

Yes on the scale controller.
I don't think we need anyway...
Is all write in the manual in case we need.

The exact model is Rinstrum R423 -> https://rinstrum.com/wp-content/uploads/2018/08/R400-600-230-M02.pdf

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p.87 describes the command structure.

Even simpler in this case may be to use the automatic weight output as described in Ch.10, p.89. The 10 Hz will be more than enough (10 measurements a second!), as all the control system really needs is the current weight. I like FMT.A, that's definitely the easiest way. One way communication only, easy protocol.

I'll also send you PM about this.