Iv had where it says the connection speed it will be showing 120-119 then drops to 0 get red colour and then back to 120 over and over after about 10mins with a CDI ignition system speed way car on the dyno.
When this happens brake comes on 100% and gives you a hell of a fright.

Work around for me has been to unplug the USB and replug it in every 5mins since it takes about 10mins before it does it.
Dont deal with many CDI ignitions tho so isnt too much of a hassle.

My biggest issue still is brake will just stop working after about 2 hours almost to the dot. Program shows its output brake but you probe the bluebox and there is no voltage coming out of it.
Same fix for that. Unplug USB and plug it back in and its good for 2 hours again. Doesn't even need to have a car or any use on the dyno. Can just leave it sitting on the run screen and it will happen.

Iv been though the same trying to eliminate all EMI on mine since the loadcell reading is a bit unstable.
Jumping around .30 with nothing on it. And jumping around 3nm with 47kg on it. Had to fit a capacitor to filter it which halved that jumping around.

Hi , are any of the wire leads going back to the yourdyno box wrapped up in a coil to make the wire cabling pretty ???

I have the same problem, is very annoying.

I have tested this device and does not help at all

https://www.we-online.com/web/en/electronic_components/produkte_pb/demoboards/usb_2_0_loesung/USB2_0.php

Shorted usb cable or ferrites does not help also. 

are you sure you guys are  getting false  input electrical noise "EMI" back into you systems? you going to have to put a oscilloscope on the system and check it properly.

In my case is a guest, we have tested a lot of options and not sure where to continue.

How do I measure with the oscilloscope this issue?

Hi, I think I have the same problem! In a run session brake doesnt work at all, but in option-->test your brake the brake works well. I'm going crazy, I do not know what to do anymore

Posted by: eric91

Hi, I think I have the same problem! In a run session brake doesnt work at all, but in option-->test your brake the brake works well. I'm going crazy, I do not know what to do anymore

Sounds like you have the PID set wrong.
Mine with the default settings ends up the brake coming on 1200rpm after its ment to. Just took a lot of playing to get mine set and even still its about 200rpm late.

Posted by: Amelia

In my case is a guest, we have tested a lot of options and not sure where to continue.

How do I measure with the oscilloscope this issue?

Hook it up in parallel with the bluebox.
Signals should look clean (Nice straight line on Loadcell) Nice square wave on speedo.
EMI will be more a issue for the internal circuitry tho. in the PC or the bluebox. Which you cant test easily.

I think is not a pid problem, because brake doesnt work also in brake sweep where pid control isnt involved. 

I have same issue also. I use yourdyno to control 1 eddy current retarder brake. When retarder starts rotating yourdyno software disconnects and reconnects fast many times. In that case it loads and unloads engine highly. Sometimes only solution for reconnection is to disconnect usb cable and reconnect. I have tested several USB cables (also very expenssives!) after 30 minutes of unstable connections the problems stops and i can use dyno several hours without problems. I have no idea on why. Have dynoed almost 50 engines now. This happens everytime.

I use SKPC power supply. I noticed, if i disconnect 0-5v signal cable from yourdyno to power supply and starts rotating retarder then issue is solved. If i plug it in problems start. Does anyone have any input? 

Does it have blocking dieodes so it's not back feeding voltage from the retarder like a generator.

Is good to see that I`m not alone, I think that I was doing something wrong.

So,  I believe if the noise is from the loadcell or the rpm sensor I would get a wrong data, but not a loose connection problem, I`ll also will give a test just to be sure.

Problem is 100% related to eddy current brake if used without brake works perfect

Thanks to MadsWP my next step was to try testing with better usb cables, so I wont throw more money to the bin for the cables as is tested

If somebody have any idea I will be happy to test it

Posted by: Amelia

Is good to see that I`m not alone, I think that I was doing something wrong.

So,  I believe if the noise is from the loadcell or the rpm sensor I would get a wrong data, but not a loose connection problem, I`ll also will give a test just to be sure.

Problem is 100% related to eddy current brake if used without brake works perfect

Thanks to MadsWP my next step was to try testing with better usb cables, so I wont throw more money to the bin for the cables as is tested

If somebody have any idea I will be happy to test it

I have the same problem but I have a hydraulic brake, so Im not sure if the problem is Eddy current brake. When I lost connection, the load cell and rpm sensor seem to work well, only the brake doesnt work at all

Very interesting, my problem is always under brake control, sometime even I get no communication from the yourdyno to the laptop and the brake is 100% on till I unplug the usb from the yourdyno, this takes me to think that I had a EMI problem, but this can not be under a hydraulic setup.

Hope Jostein can help us with this issue

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.