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Extending Load cell wires

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(@edgars)
Posts: 28
Member
Topic starter
 

Hi!

I am working on my hub dyno and right now come up with one problem. I have made box for controlling retarders where is wired up yourdyno controller and Semikrons. I am using 2 cables for each retarder. One for DC current for retarder and other 9pin cable for sensors - rpm, load cell, aux signal. I don't want to wire seperate cable for load cell, cable for rpm sensor and even aux signals. It would be a big mess. It wouldn't be a problem with static dyno, but hub dyno is meant to be moved and 4 cables for each retarder isn't nice.

So my question is - how to extend load cell wires? I know that they aren't intended to change length, because it will effect on sensitivity of load cell.

Normally load cell cable is 3,5m long and this is still to short for me.

dyno box

dyno box 2

 

 
Posted : 26/02/2019 9:41 pm
(@bmgjet)
Posts: 362
Dyno Wizard
 

Mines about 10m long. Main thing is it needs to be shielded.

 
Posted : 27/02/2019 12:43 am
(@edgars)
Posts: 28
Member
Topic starter
 

and working without problems? Have you ever tried to find out how big is this possible "error" in measurement by using 3 times longer wires? 

 
Posted : 27/02/2019 12:56 pm
(@slider)
Posts: 16
Member
 

I have also about 10m long shielded cables for hub dyno, working with no problem. I have 3 cables going to brakes, wrapped with fabric heat shrink tube.

 
Posted : 27/02/2019 1:23 pm
(@walter)
Posts: 244
Member
 

I use "cable apantallado (in spanish)", not sure how it's called in english. any problema after +1 year.

 
Posted : 27/02/2019 1:40 pm
(@edgars)
Posts: 28
Member
Topic starter
 

o.k. I tested again my wiring and don't know what is happening.

I can't calibrate load cell. all the time measurement is fluctuating. I took of my wire and connect load cell straight to yourdyno controller, but still the same. Can't calibrate it. Connected all 5 wires like it should. Attached link to video. Don't know what is happening, because it is same for both load cells.

https://photos.app.goo.gl/nZj5YoPUpV2Wt5Km9

I have wired cell like this:

 
Posted : 27/02/2019 10:50 pm
(@bmgjet)
Posts: 362
Dyno Wizard
 

Are you using a laptop if so run it on battery only to isolate it being charging noise. If it's a desktop I had to use a capacitor on mine to remove noise. There is a thread on it I'd post a link but it's hard on my phone trying to copy paste

 
Posted : 27/02/2019 11:47 pm
(@edgars)
Posts: 28
Member
Topic starter
 

No, I am using laptop. And it is running on battery. Not plugged it.

 
Posted : 28/02/2019 12:30 am
(@edgars)
Posts: 28
Member
Topic starter
 

Still trying to get normal results from my load cell. And then looking in datasheet I found out that excitation voltage is shown: 8-15V. So I think this is problem, because Yourdyno is giving only 5V. Am I right? 

Attached load cell datasheet.

 
Posted : 05/03/2019 7:44 pm
(@admin)
Posts: 1397
Member Admin
 

I see no reason why this load cell should not work. 

Can you show us a video from the calibration process? 

 
Posted : 05/03/2019 11:47 pm
(@hondarulez)
Posts: 38
Developer
 

To be more accurate measurement I'm able to drive directly the Loadcell's +/- input by a low impedace driver ?

bypassing the sensor's supply voltage, if yes what voltage range allowed ?

I will using PWM and 100V DC powersupply with telma AD-72 2KNm retarders and long sensor wires. So I'm trying to get the best.

This post was modified 5 years ago by HondaRulez
 
Posted : 26/04/2019 5:58 pm
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