One more picture 

Hi, the weight will be "crazy" before calibration. Did you calibrate it? 

A good check is to watch the raw load cell value. When still, it should vary between +/-20 or thereabouts. This is on a scale from -32000 to +32000. 

@admin

yes l have tried to calibrate it! but it dosent make any change ! it still vary between those numbers. its impossibly to get it to zero . 

im going to try it again and see if it works

best regards 

glenn 

@admin

I have tried again now!.

This time it was possible to zero calibrate the load cell but when l load it, it starts to gouup and down a lot!

 the raw loadcell reading is about 380-385! What that does mean? 

The Raw value is the digitized value of the load cell reading. It shall stay fairly stable when you are not not toughing anything. 380-385 is perfectly fine. Then when you push on the arm you shall see it changes to several hundred, and more when you press more. 

Load cell cal is done like this: 

• Ensure no load on the arm and press Zero calibrate
• Put the calibration load on the arm. You will see the raw value increase (it can also go negative depending on the wiring). It will stabilize. Press Load Calibrate
• Press Save calibration

Check that the reading is correct (0 kg at 0 load) and the load when the load is on. 

How are you applying load to the arm? The "Torque arm length to load cell" number is the distance from the middle of the brake axel to where you place the load. The load is typically placed over the load cell, but does not need to be. You enter the distance to the load if not over the load cell. 

Thank you.

I have done as your instructions but the problem is that the raw value is the same all time 380-385 ( with or without load )  

I'm not 100 % sure how to wiring this load cell but l have tried all different ways without success.

So l guess something is broken? 

I have also tested 2 load cells from yourdyno and it showed a raw value of about 200 when it was zero calibrated! Isn't that wrong too ? But the weight was correct with this one. So l guess it's fine? 

If the raw value does not change when you apply load, then the connection is wrong. There is no way to calibrate when the raw value does not change. 

I am not familiar with the L&S load cell. It has 4 wires, right? Load cells are in all cases I have seen made as a wheatstone bridge (google it if you are unfamiliar). There are a few correct way to connect it and a few incorrect ways. But it is strange that it does not change at all. But how are you actually applying the load? Looking at the brake picture you need to remove the arm holder on the right and lock the brake from rotating. 

200 when no load is normal. This is 200 on a scale from -32000 to +32000. It equals a tiny voltage. 

@admin

ok

yes its 4 wires . 1 ground and 3 to the strain gauge. 

here is a calibration video. 

https://www.youtube.com/watch?v=sfnOHEcz6eY

im going to read about wheatstone bridge and maybe l can figure out someting

best ragards 

Glenn 

OK, so you have first done a 0 cal without the load connected, right?  The load looks small and I would place it as far away from the center as possible (and then update the load cell arm length), but it should still work with the load placed like you did. 

Anyway, there is something wrong with the load cell or the connection if the raw value does not change when you apply load. 

yes l have first done 0 cal. 

l have also tried another weight of 20kg with the same result. 

next step is to try another cable. if that will not work lm going to modify the brake so l can use a regular load cell. 

@glennt, ok. We have the same brake (only larger) and we use a load cell. I never tried the built in load cell from L&S. 

Hi Glenn have you had any joy in getting readings from your strain gauge yet? Would like to do the same as I have a similar L&S kart setup but data box not working correctly! L&S not very helpful And expensive ! Any help greatly appreciated. Cheers Austin 

Posted by: @austin-jones

Hi Glenn have you had any joy in getting readings from your strain gauge yet? Would like to do the same as I have a similar L&S kart setup but data box not working correctly! L&S not very helpful And expensive ! Any help greatly appreciated. Cheers Austin 

Hi Austin 

It's not working for me and l think it's because the strain gauge is missing a wheatstone bridge .So you can only measure resistance. If you complement with a wheatstone bridge it should work.

I decided to make a new torque arm instead of trying to solve it with a wheatstone bridge .

I bought a single point load cell and made a  new arm. See pictures 

Thanks for getting back to me!  I had not thought of making making a arm to use that type load cell!  But as I have the L&S trolley makes good sense to use that setup! We build gx clone engines so that keeps it simple!  What kg is that load cell and what hp range are you working with if you don't mind me asking?  Thanks Austin