Hi Jostein,

From the list I have already done some stuff.

• YourDyno box is grounded
• Brake control shielded with yourdyno graound
• All powered cables are not less than 3 meters from yourdyno control box
• The power supply is 7 meters from blue box
• this problems occurs under diesel and petrol, so I guess that the problem is not ignition coil related
• 5volt is used correctly, just for rpm and loadcells

What optocoupler between YourDyno and the brake power supply y can set for an analog 0-5v cheap

Thank you

Amelia, which power supply do you use? 

I have tested 2 Transformers, on is semikrom based and the other one is sold by frenelsa named as var10 I Will search for the papers and post them here. This last one needs to be used with a galvanic insulator to protect the controller , with both I have the same problem, I use a cable same as the loadcells shielded from the yourdyno to the transformer

I checked the VAR10. Indeed it needs a galvanic isolation (for example an optocoupler). Since it needs an analog signal, you can use PWM + a digital optocoupler, then use an RC filter to generate an analog signal. Or you can go for something like this: 

https://www.dfrobot.com/product-1621.html

Note that this circuit includes a DC/DC, which you don't use. So connect like the attached pic shows. Put the analog isolator close to the YourDyno box.

I have tested with a galvanic insulator near the power supply, I will test to change near the yourdyno, thanks

Hi we have had similar issues on a motorcycle Dynojet dyno and it turned out to be frequency and harmonics as a bearing was failing and again on a bike that the head stay had cracked

It got that bad it even turned of the rcd for the power supplyas it replicated the frequency required to trip ? 

And did you solve the problem? 

Sorry yes it cured our problems

Not saying it is the same but I went grey over this one but it's something I don't really understand. but I now have an appreciation for the people who do 

Sorry, I dont understand, how did you solve the problem?

We noticed a pattern as to when this happened. it always happened at certain revs either on the power or just coming of.

We didn't now at the time but the starter we used to start race bikes failed so on replacing it we checked everything and found the drum bearings were not good changed them and then noticed we never had the same issue of the graph dropping out it had been resolved

And when we had the old norton on the vibration or resonance seemed to change it's feeling a bit like pins and needles and that was shutting everything down  We could manage a reading

Now after some experiment, with the help of Jostein I solved my problem, was a brake setup issue.

Hi, how did you do to ground the blu box? 

Posted by: eric91

Hi, how did you do to ground the blu box? 

I used the ground from the AC power, this ground goes with the  ground of all the building, same as any power device is grounded

The ground of stepper driver is the dc- wire correct? So its the V- of all other power supplies correct? Sorry but Im not very strong with electronic

Sorry I`m not used to that device also I can`t guide you, but sure other from here will