A bit OT. Anyone knows where to source load cell calibration units ?

Hi.

Do anyone know if there are exist any supplier of ready-to-use load-cell and display units, calibrated with certificate and all ?

I have been fiddling with how to setup such a device for my companys servicepersonnels use, and to sell to customers who also want to perform calibration by themselves.
But it is a mess of finding a loadcell, finding an adapter, connecting them together, and having the whole thing sent to a certified calibration institute in order to be able to put a calibration sticker on the thing.

Is it not possible to purchase such a thing already ready to use ?
We only need to calibrate compression load cells up to 2 kN.

What you are describing is a portable scale, and they do exist.

But I think that isn't really what you want, is it? You want some scale parts, that you install to build a complete scale.

The problem is that load cells need to be calibrated after install, as there are a number of things (like installing some of them upside down, damaging them, friction points, etc) that can invalidate the calibration. My company builds portable equipment that includes scales, and these require re-certification after each time the equipment is moved to a new location...a pain, but justified, as improper use of the locking provisions, welding to repair moving damage, etc. have historically been issues, so I can see the sense in it.

Scale calibration services are widely available. A licensed tech will show up with test weights, hoists and carts to handle them, and calibrate on site. I will also add that in my experience, these guys are very knowledgeable and helpful when it comes to diagnosing a scale that isn't working right.

The calibration loadcell must be able to install in a machine, inline with the loadcell that is to be calibrated. The measured value is force, not weight.

If that had existed, the scale calibration services would use such things as well. My experience is the exact same as indicated by Kevbo: calibration service techs bring their own test weights to perform their calibration work, not some other calibrated device. That is the industry standard way to go about.

Not sure if this will help, but try to have a look at "Hardy Process solutions" they have load cells with C2 (eCal) software calibration.

Not totally ready out of the box, but the idea is that you can calibrate the load cell without using weights, I haven't testet them myself, but they are on my to do list

/Holm

Pancake type or button head type?
Can the load cell meter be 120 volts?

the issue I see is that you are inserting your load cell into the mechanical system and therefore only getting a close reading. True, the numbers will be close or even match, but what happens when you remove the load cell from the mechanical system?

the installation has then changed. you may have to shim the load cell backing or modify the system to obtain the zero tare.

If my memory is correct, we bought a load cell and sent it to daytronics for calibration on one of their meters and got a calibration cert. don't remember the price, but that was 20+ years ago. we used an s beam 10 k load cell.

james

James Mcquade said:

Pancake type or button head type?
Can the load cell meter be 120 volts?

Click to expand...

Pancake if possible, but button head could work too.
If the meter isnt battery powered, it should have universal 120/230V supply.

James Mcquade said:

the issue I see is that you are inserting your load cell into the mechanical system and therefore only getting a close reading. True, the numbers will be close or even match, but what happens when you remove the load cell from the mechanical system?

Click to expand...

The loadcells in the machine are vertical and presses from the top, so the calibration loadcell will not affect the machine loadcell, other than a part to be pressed would do. (*)
I think that if there were any differences if the machine loadcell was removed for calibration, then what good would the calibration actually be ? We need that the measured value from the loadcell in the machine is calibrated. That means the whole signal chain including the mechanical setup is calibrated, nut just the loadcell itself.

*: @Toine. You can see that this design means it is not possible to calibrate the loadcell in the machine using weights. The wast majority of load cells are used in scales, but in this case it is not a scale.

Holmux said:

Not sure if this will help, but try to have a look at "Hardy Process solutions" they have load cells with C2 (eCal) software calibration.

Not totally ready out of the box, but the idea is that you can calibrate the load cell without using weights, I haven't testet them myself, but they are on my to do list

/Holm

Click to expand...

I found this on their website:

What is a C2 system?
A C2 system includes load points, junction box, cabling and instrumen- tation, and is designed to make calibration easier than ever before. Upon installation or re-calibration, your Hardy instrument automatically searches for C2 certified load points and records their performance character- istics. Entering a reference point is all that’s needed to bring your system on-line within seconds. On instruments with “THE BUTTON” feature, one touch of a button is enough. All that’s left is to verify your scale. This is done by carefully distributing one or two small weights (25 to 100 lbs.) on to the scale so they are shared by all the load sensors. The scale reading should equal the value of the test weight(s) applied. Remove the weight(s) and the scale reading should return to its original value. If both of these are true then the scale is calibrated, verified and ready for use! If the values are not true, then there are mechanical problems with the scale that need to be corrected.

Click to expand...

The underscoring is by me. As I read it, you actually do need some weights, only they are small and not the full load of the scale. Applying weights is not possible in my case, no matter large or small.
To clarify, they write "all you have to do is to verify your scale [by using weights]". Well, verification is part of what I mean by "calibration".

Holmux said:

Not sure if this will help, but try to have a look at "Hardy Process solutions" they have load cells with C2 (eCal) software calibration.

Not totally ready out of the box, but the idea is that you can calibrate the load cell without using weights, I haven't testet them myself, but they are on my to do list

/Holm

Click to expand...

I have used these systems a few times now. One under two 25000KG grain bin,,, works awesome.. C2 calibration makes it a joke to calibrate.

One system under a pair of mixers as well, even with the continuous motion they do very well.

Hope this isn't off topic,, just had good experience with this!

PLC Pie Guy said:

I have used these systems a few times now. One under two 25000KG grain bin,,, works awesome.. C2 calibration makes it a joke to calibrate.

One system under a pair of mixers as well, even with the continuous motion they do very well.

Hope this isn't off topic,, just had good experience with this!

Click to expand...

I had a good feeling about this product, I have used their weighing modules for compactlogix a few times with great success, I have a project coming up where I need to build 3 scales and I am planing to use Hardy cells.

So good to hear the C2 calibration works

/Holm

Iv installed C2 load cells under 6 vessels totaling 28 load cells in all. Never had to replace any yet nor did I find any bad units during start up. Do make sure to use the specified C2 cabling. I tried to cheap out with Belden shielded cable once as I thought it "wouldn't matter"...... It does matter, trust me. Its C2 cable now as the scale would work with manual calibrations, but the C2 function couldn't find the sensors without it.

Also, the Summing card boxes Hardy sells are overpriced and are NOT water proof as they are rated. I have purchased the C2 summing cards separate and put them in my own enclosures. The last project I did, I purchased the Hardy boxes and put them inside of another enclosure to be sure they will never get moist. Money wasn't an object on that job!!!

Somewhere on Hardy's site, there is a running HI4050 controller that you can connect to and see the configuration, mapping and operation screens on. Its exactly what you see when you set up your own scale unit. I'm sure that Hardy could provide the link for anybody interested.

JesperMP said:

Hi.

Do anyone know if there are exist any supplier of ready-to-use load-cell and display units, calibrated with certificate and all ?

I have been fiddling with how to setup such a device for my companys servicepersonnels use, and to sell to customers who also want to perform calibration by themselves.
But it is a mess of finding a loadcell, finding an adapter, connecting them together, and having the whole thing sent to a certified calibration institute in order to be able to put a calibration sticker on the thing.

Is it not possible to purchase such a thing already ready to use ?
We only need to calibrate compression load cells up to 2 kN.

Click to expand...

Check these guys https://tacunasystems.com/zc/ , very reliable company specializing in tools for sensing, data acquisition, and controls. They provide with load cells, load cells accessories, load cell calibration services, etc. Seems like just what you're looking for.