Does anyone have any experience with an industrial scale that I can use to weigh veggies, in the range of 50-60Kg, and can easily communicate with an Arduino? I need it for a client that needs to calibrate the average weight of a sample of product, so it would be counting the units that get into the bucket and then give an average weight
Thank you
Many moons ago I used a number of scales and their 'computer' interfaces were a simple serial link that sent out a continuous stream of data (start character, data packet, end character), usually in ASCII, that told you about what the scale was doing, including the weight. Very simple stuff, but effective.
I would expect that these days there will be more options and the RS-232 interface will have migrated to USB or Bluetooth, both of which are easily interfaced to the Arduino. The main thing from an implementation perspective is that they have documented the interface and make it available freely, the rest is just software.
A simple search for "industrial weighing computer interface" showed a lot of options.
I think what you are after is "counting by weighing". The scales which are popular for this are commonly called counting scales. I would be looking at counting scales which can be interfaced using an interface you can read with an Arduino. Most I remember were RS232 and that was a long time ago. Today many offer USB and many still offer RS232. This is an example but comes up a little short in weight capacity.
Ron
Ok, what's the benefit of a counting scale? I was ready to include this function by program, using an "average expected unit weight", also a "maybe +/- 25% expected deviation", and working like everytime this expected weight is added to last reading, I have one more. Then wait for 50 units, and divide total weght by units. Not sure if relying this funcion to the scale would
Also USB connection is not the best I would take into an Arduino, usable but not ideal. I would prefer pure RS232.
I have found lots of scales that seem to comply, but I am completly lost in which provider sound reliable, this is real project for a big manufacturing plant and this thing can't fail in 6 months
Thank you
The benefit is if I sell items in bulk. Nails for example. Customer wants 500 nails. I enter the weight for one, five or ten nails as a sample and my scale tells me how much weight 500 nails will be give or take a few nails so I scoop nails on the scale platform until the now preset weight is met. Again, using nails as an example this is subject to a tolerance.
I buy once fired US Government rifle brass in bulk. When I order 1,000 pieces nobody sits there and counts out 1,000 pieces. They weigh them and normally once weight is met toss in more to make for a happy customer and no, I never count them when they arrive at my door. 
A single piece of 7.62 mm brass weighs about 179 grains. There are 7,000 grains to the pound so if I ship 26 pounds to a customer who ordered 1,000 pieces they will be happy.
Also USB connection is not the best I would take into an Arduino, usable but not ideal. I would prefer pure RS232.
I have found lots of scales that seem to comply, but I am completly lost in which provider sound reliable, this is real project for a big manufacturing plant and this thing can't fail in 6 months
Then you use components from a reliable source and reliable brand name. Ohaus comes to mind. You also find a scale with the uncertainty you want (accuracy) and the weight limits range you want. Simply put, I do not suggest a no name scale with no manufacturer support, off the boat from China. You buy known quality. You also buy the interface you want and as I mentioned RS232 remains popular. You cannot directly interface RS232 to an Arduino. Additionally most better scales include a software bundle allowing direct PC interface to Eindows and some MAC and some a SDK to roll your own. You don't use hobby crap for a commercial industrial application.
Ron
Ok now I understand the counting function, but I wouldn't be using it. I would need to interactively modify the average unit weight and deviation, not using the builtin scale panel but inside the Arduino program.
So I would implement this tunction inside.
Yes I want to stick to a reputable company that provides end user support and real warranty and find a local distributor for it. I would be using RS232 when possible and probably the usual MAX232 for interfacing or MAX3232 for 3v versions of Arduino)
I will take a look at those manufacturers, thanks a lot for your help!