I have little experience with industrial wiring and if no one else here has, then you may want to trawl some of the forums covering industrial control or have a look in your local library.
But I do know that although its common to use optical isolators in noisy industrial environments, you may not need to worry about this unless there is a lot of electromagnetic interference in your environment. Is there?
You can mount the Arduino in a shielded box located near the sensors. (you have one weight sensor one photocell, and an encoder) and they can be much less than a meter from each other and the Arduino box) The power supply for the Arduino should be separate from the power supply for the solenoids. The only long wires you need are to the solenoids and the wire choice for those depend on the current demands of the solenoids, have you chosen the solenoids yet?
Hi, mem.
Yes, I've choosen a solenoid and you can check it here. http://www.flickr.com/photos/23525729@N06/?saved=1
It is 12VDC solenoid. The triggering arm extends up to 5.4mm. I don't think this is enough to trigger the moving carriers so I asked the solenoid company to make solenoids which goes up to 10mm while keeping the same triggering strength. They say it's possible. It costs around 2 dollars per each. When its ready, I will show you.
Can I use computer power supply to power arduino, encoder, indicator and solenoids? I am not sure what kind of power supply is suitable for my application.
I will also look through google search to know more about power supply.
Do you have a datasheet for those solenoids and can you get info on the current requirements for the longer stroke version you want to use? It would be worthwhile asking your solenoid supplier for his recommendations on power supply rating for the number of solenoids you plan to use. Its important to tell them that all the solenoids can be triggered at the same time. Also give them an indication of how long the trigger pulse will last at the slowest speed the belt is likely to move.
You could probably use a computer power supply to test the solenoids if they don't consume more power than the supply can provide. But I don't know if they are robust enough for your application long term or if noise spikes from the solenoids will affect the 5v supply that will power the Arduino.
There are a number of articles on the web describing how to convert a computer power supply to get 12v and 5v. Have a look on google but here is one link that will give you an idea of what needs to be done:
Hi, mem!.
Thank you for your advise. I will consult with the solenoid supplier about the power source I will be using to control solenoids tomorrow.
Also, I will get the data sheet.
i will get back to you soon. Have a nice day.
The resistance of the solenoid I'm using is 11 ohm.
The current is 1.1A and power consumption is 12W.
I need to use 24VDC if I want to use a solenoid which has 10mm stroke. So, I am thinking of applying 24VDC to solenoids in order to get 10mm stroke.
The industrial power supplies are quite expensive. I am continously studying which power supply is better for my application.
One of the guy from the solenoid company said it is no problem for their solonoid to get trigger pulse as long as I keep it less than a minute.
The solenoids don't require the smoothing and regulation of a professional bench power supply but you will need one that is robust enough to handle the peaks.
Because it is possible that all solenoids need to be triggered at the same time, your supply needs to handle the peak current times the number of solenoids.
How many solenoids have you decided to use?
That 1.1A /12W 11 ohm figure looks like it is for the 12 volt version can you check the figures for the 24volt version and also get the peak current requirements.?
Perhaps the solenoid company can give you guidelines for selecting a power supply for their solenoids. It will be less expensive if you can use an unregulated 24vdc, perhaps even something like a 24volt battery charger of suitable current capacity.
Hi, mem.
Currently, I am thinking of using 15 solenoids. 5 solenoids per each range of weight designation.
Yes, 1.1A /12W 11 ohm is for 12 volt version. I also asked the guy to tell me the figures when solenoid is 24 volt version. He will reply me soon.
They don't exactly know about computer power supply. So I couldn't get proper advise in this regard.
I will experiment with computer power supply using 12vdc solenoid first and then I will test it with 24vdc version.
The structure is taking its shape. You can check it here. I had some fun with welding. but my skill is awful. ;D http://www.flickr.com/photos/23525729@N06/2340661166/ http://www.flickr.com/photos/23525729@N06/2339803175/ http://www.flickr.com/photos/23525729@N06/2340635178/ http://www.flickr.com/photos/23525729@N06/2339802057/
The carrier pitch is approximately 100mm. Tomorrow, i will get steel plates to make carriers.
I am thinking of using some LCDs to display the weight ranges on each designated location for certain weight range.
That way, I think I can easily distinguish which weight range is allocated on the first designated location and so on.
Could you teach me how to incorporate some functions in the sketch to display the weight ranges(such as 100g - 110g kind of numbers)?
I think LCDs would look very nice on the conveyor. if I can do it, I will cut some small parts of conveyor body cover and put LCDs on.
What do you think of my idea of using LCD? If there is much more cool idea, please recommend me.
A computer power supply should drive six or more of the 12v solenoids for testing, but I don't think you would be able to drive all 15 solenoids at once.
Once you know the current requirements of the 24v solenoids you can start looking for a power supply for these. I have seen some available surplus that would probably be good, although too heavy to ship internationally. Where are you located?
There are a few ways you could display the weight range for each solenoid on an LCD. One method is to have a single LCD display with a menu to select the station to display. You could have a button (or buttons) that sequenced through the stations, displaying the current weight range on the LCD screen and lighting an LED by the selected station.
Another set of buttons could be used to adjust the lower weight limit of that station (assuming the upper limit was the lower limit of the next station ).
You could also use a pot for selecting the station or setting the weight instead of buttons.
You could also have a second LED for each solenoid station in a different color that lights up as soon as an object in its weight range has been weighed and remains lit as long as any objects are within that solenoids weight range on the conveyer.
I think you would need to use a second Arduino for the control interface because you are running out of pins on the main Arduino.
It's great to see the metalwork taking shape. Keep those pictures coming!
Hi, mem.
The 24vdc solenoid has 22 ohm, 1.1A, and 26W. They guy from the solenoid company said there is no particular power supply for using their solenoids as long as it provides regular voltages to each output pins.
I love to see the available power supply you've seen. I am in South Korea.
I think it must be cool to apply the LDC function you've mentioned.
Will this LCD do for that function? http://www.eleparts.co.kr/shop/view.php?cate1=14&cate2=75&cate3=&cate4=&item=2363&keyword=&page=2
That LCD should be OK but check that the interface is Hitachi HD44780-compatible.
You may also want to confirm if it is back-lit so its easy to see if the lighting in the room is a little dim.
I should think you would not have difficulty finding a suitable power supply in Korea. If you are in Seoul, have a look in the Yongsan electronics market area (I have spend many happy hours there ). You need about 400 watts at 24v for your solenoids, It my be cheaper to get two 200 watt supplies.
The power supply I saw was in the USA, it was big and heavy and would cost far more to ship than a new supply ordered from Korea or China.
That's wonderful~! I'm so glad to know that you have some travel experience in South Korea.
The place I am located is very far from Yongsan city. But since there are many websites I can search for, I can do it.
The LCD I've posted has no back-lit function. I will searching.
Thank you very much for your support.
i just hooked up a couple LEDs see if everything was working, both LEDs flash no matter which way i turn is this normal or have a bought the wrong one??
i've plugged it into max and the print screen comes up with the numbers 10, 13, and a changing number between 48 and 57??
i just hooked up a couple LEDs see if everything was working, both LEDs flash no matter which way i turn is this normal or have a bought the wrong one??
i've plugged it into max and the print screen comes up with the numbers 10, 13, and a changing number between 48 and 57??
Hi, mem.
Today, I've searched for power supply and LCD and I am planing to visit few shops.
I've ordered sprockets today. I couldn't find any usable sprockets from the scretchs around me.
I will use four sprockets for the rotation(two per each side). Once I successfully attatch the sprockets to the structure, i will post some pictures.
Since I am doing the conveyor making process all by myself, it's taking quite long time. But I am trying my best not to make mistakes even if it takes more time and more process. If there hasn't been your support, i could not have been able to attempt to actually make something from my imagination using arduino. i'm very thankful.
I will keep coming back with updates.
Hello, mem.
I have came up with a concept which involves a capability of processing different distance between weight check point and solenoid.
Please check this drawing. http://www.flickr.com/photos/23525729@N06/2347125048/
As you can see, the approximate distance from the weight check point to the first solenoid is 757mm and the distance between each solenoids is 150mm.
Will this be possible?
hi mingki, I am sure its possible to modify the code to cope with the weight sensor at that distance if that makes the construction easier. I will need to give some thought on the best way to do it. One way is to make the ObjectBuffer bigger by 5, if the distance from the weight sensing position to the position where the first solenoid is activated is around 750mm. Remember that the sketch logic assumes that the conveyer will have an object over the weight sensor at exactly the same time as an object further down the conveyer is over a solenoid position ready to start to drop. If we change the que logic we can make this 5 cycles later rather than 1 cycle later as implemented now.
Have you determined the distance between the solenoid activation and deactivation points so we can see how critical the spacing between the weight sensor and drop points will be?
Hi, mem. Thanks a lot.
Yes, it will enable me to position the outlets much easier. Otherwise, I must cut and fabricate outlet parts in a way that it fits into its precise position and the length of this conveyor would be unnecessarily long. That's why I want to keep those outlets closed together each other.
I don't have exact distance measurement between the solenoid activation/deactivation area.
Because, I haven't decided the main chain's pitch yet. it's because I am trying to use some attachments on the chain(2060H) to attatch the carrier boards. This is the cheapest and ideal way for me at the moment.
I have decided the pitch of the each carrier though.
It is 120mm x 130mm. The width(horizontal direction) is 120mm and the length(height) is 130mm.
Am I following you in the right way?
If it's not, could you please correct me?
The important thing is to try and position the weight sensor so that the object will be in the correct position over the sensor at the same time that the objects further down the conveyer are ready to be dropped by activating the appropriate solenoids. If this is difficult to determine now, can you mount the sensor in a way that its position can be adjusted closer or further from the first drop point by a few cm. This may not be necessary if that is difficult to do, but may avoid adding complexity to the sketch if you can easily mount it so it can slide forwards or backwards by at least 20mm each way and you can get the center point close to the location suggested above.
But its easier doing stuff in software than in hardware so don't worry if this makes the fabrication too complicated.
I've thought about making the weight check point to be adjusted a little bit about 20mm as you've mentioned.
I am checking the structure I made and imagining which part of this structure is the best to be equiped with weight check point.
I think I must cut the profile in half(or assembe two identical profiles in a row) so that I can put weight check point between those two identical profile.
I think I can make some room for the weight check point to be adjusted side to side but, there is a big danger of collision between groove cover and weiging structure(area).
The groove covers can be seen through this link. http://www.arin.co.kr/bbs/zboard.php?id=AL_Profile&category=3
I will attach a groove cover under each carrier board so that the carrier board could run on a profile(profile will also have groove cover) while withdstanding friction, heat and avoid noise but I will cut groove covers 18mm to 20mm so that I could keep the friction area as small as possible and I can make the whole carrier to be very slightly droped onto a loadcell. I wish I were an expert in this area but this is the only mechanism I can come up with for accurate weight checking system.
I hope below drawing could explain what I have in mind. http://www.flickr.com/photos/23525729@N06/2346882737/sizes/o/ http://www.flickr.com/photos/23525729@N06/2347712538/sizes/l/
But, I think I can avoid collision by extending the length of the groove covers under carrier board.
I wish to hear your opinion.
I have less expertise than you with the mechanical engineering side of this. Ensuring that the weight sensor is getting meaningful readings is critical so its worth spending some time on the internet searching for common techniques for doing what you want. And I am sure there are industrial control forums that have expertise you could tap into.
I am going on vacation with my wife and will have limited access to the internet for about 10 days from this weekend. I hope that all goes well. And don't worry too much about the software side; I am sure we can make the sketch work no matter where the sensor is located. But you will need to be sure that the sensor does provide the correct weight.
). You need about 400 watts at 24v for your solenoids, It my be cheaper to get two 200 watt supplies.