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

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

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

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

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

Sorry, I dont understand, how 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 

And did you solve the problem? 

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 ? 

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

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 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

Amelia, which power supply do you use? 

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

Hi guys,

There are a few different issues you describe. 

Here are a few things to try if you have a eddy brake and you see connection drops when you start the brake/run the brake hard. That can be EMI related.

• Ground the YourDyno box
• Use a shielded brake control cable. Remember that the shield shall only be connected to ground in one end (important, otherwise you may get current in the shield which is no-no). Connect shield to box ground
• Route all other cables, especially high power and/or noisy cables, away from the box or any cables going to the box (very important, distance = less EMI problems)
• Mads, you may put the SKPC power supply in a metal box and ground the box
• Non-resistor spark plugs are known to be very noisy. Many ECUs have warnings about this, so always use resistorized spark plugs
• If you replace the USB cable, check out the wire gauge. Go for AWG22 for a 3m cable or AWG24 for a 2m cable for the power pair. Lower AWG number = thicker cable conductors, which is important since the box is powered by the USB cable
• Don't use the V+ RPM power and the 5V load cell power for anything else than what it is intended for (RPM sensor and load cell)

If non of the above works, you can add an optocoupler between YourDyno and the brake power supply, for example this. Super cheap, works only for digital (PWM) signals. 

I will try to figure out why the brake stops working after 2 hours, this is a different issue. I have seen this occasionally, but not regularly at 2 hours as you describe, bmjet. It is probably a simple fix though, I can just send the brake configuration status to the YourDyno box once in a while instead of just once when the box boots up.

Eric, I will contact you separately, the problem you describe is very different, and probably a setup issue.