Going to DD after TS-PC, which one though?

[Deleted member 197115]

Definitely symptoms of improperly grounded motor. You need to fix that before something bad happen. Check with Fanatec support, describe the problem, may be you need to replace your unit.

Or just send it back for a refund and get SC2 and live happily ever after.

 

[Navigator]

You really think so?
Damn......
Is there a way to measure that?

 

[RasmusP]

You really think so?
Damn......
Is there a way to measure that?

If I've got that right, the dd1 seems to put some voltage on your rig?
I guess it's either the screws or the whole wheelbase housing.

Or the pedals are putting something on the rig, which interferes with the properly attached DD1.

But I don't really have any knowledge about these kinds of things. I guess you should switch on the dd1 and check your rig against ground.
Not sure where to get ground from in this case though. Here in Germany, all wall-plugs have a nicely visible ground:

 

[Navigator]

RasmusP, thank you so much!
Turns out, the wall sockets are the same here in the Netherlands: I can work with that.
I had a hard time figuring out how to measure: something I should know......I'm a bit upset about the whole thing and it interferes with my thinking I presume.
It's really sickening and I am a bit scared.
Well, off to go and measure: I will let you all know!

 

[RasmusP]

Turns out, the wall sockets are the same here in the Netherlands: I can work with that.

Ah you're from NL! Yeah then the wall sockets are indeed very much identical
Little fun story:
I remember my dad going to stick his multimeter into the wall socket to get ground and my mom freaking out about us kids going to stick pointy metal things into the wall sockets.
My dad simply replied:
1. I explained to them how they work
2. They would have to stick 2 things quite far into both holes at the same time. Even if I'd want to, I'd have a hard time electricuting myself!
My mom rolled her eyes and I said: "it's okay, I know that I should only ever touch the curvy thingies at the sides and never poke into the holes".

My mom & dad started to laugh and I had no idea why, since it was a serious topic and I was 6 years old

 

[Navigator]

Lol, good story!

Well, I measured between the rig and the ground outlet, see picture............
Doesn't seem right? It's flat when the wheel is off, this happens when the wheel is on.

 

[RasmusP]

Lol, good story!

Well, I measured between the rig and the ground outlet, see picture............
Doesn't seem right? It's flat when the wheel is off, this happens when the wheel is on.

View attachment 682809

That's definitely not right with my little knowledge
That's 8.5V on the right, right?

Can you share some pictures of how your dd1 is attached to the rig?
I guess a mail to fanatec would be a good idea, with pictures of the mounting and this scope shot attached.

 

[Navigator]

The voltage AC is 8,55 V indeed and the DC is -0,2 V

When I ground my rig, it goes away, only AC 0,78 V is left.
But now my question is: should I ground it, or should the base NOT put "so much" power on the rig?
I need to be a bit more sure before Fanatec starts laughing at me

Sorry, forgot: the base is mounted with the 3 mounting holes at the underside of the base. They do make metal contact with it as there is no way around that.


@blekenbleu
@GeekyDeaks
@Neilski
@Andrew_WOT

Sorry to bother you guys again, but this topic seemed to be solved yesterday as far as you are concerned and you may not look at it anymore
But there is still a problem and you guys seem to have the most knowledge about this stuff.
Question I am asking myself now is: should this voltage be set on the rig or not? So, is the base at fault, or is it normal to ground the rig?
I mean: nothing else is connected to the rig, it must be the base. The voltage is there when I switch the base on.

 

[blekenbleu]

nothing else is connected to the rig, it must be the base.
The voltage is there when I switch the base on.

If,

• by "nothing else" is meant: "only wheelbase is connected to rig"
• 8.5VAC is measured between the rig and the ground outlet

.. then 8.5VAC would also be measured on wheelbase case if it was NOT connected to rig,,, right?

Some devices have EMI/RFI filter on power input,
a network of e.g. inductors, capacitors and perhaps surge suppression devices.
These may be required, e.g. by FCC regulations in the U.S. for Part 15 certification.
Their purpose is to drain RF energy (to ground).
Here, Cy pair represent a voltage divider between power line L and neutral N, feeding to ground:

Two Stage EMI EMC Filter RFI Power Line Noise Power Supply EMI Filter

If connection between grounds is poor, then some AC voltage will be read.
One would measure half of line voltage,
if ground connection is completely open and meter has infinite input impedance.

FWIW, some equipment internally generates so much RF energy that,
even with fully isolated input power (by transformer),

several Volts of RF energy were measured between shielding case and ground.

the DC is -0,2 V

That may be measurement artifact:

• thermocouple effect
• meter DC electronics may be rectifying AC
  

 

[Navigator]

Thank you for your response blekenbleu.

In that light, can I presume you are saying the wheelbase must be at fault, is that right?
It is only the base connected and indeed, the rig/ground outlet wall is 8,55 VAC.
I did ground it for now and of course the is no volts between them anymore. I do not see a huge difference though.

 

[blekenbleu]

wheelbase must be at fault

I do not know, because unfamiliar with that wheelbase.
It may be as designed.
A filter as described should have 3-wire power cord,
so that exposed metal is always grounded when powered,
and ground current should be less than 1 mA.

 

[Navigator]

Thank you blekenbleu!
I checked and the power cable of the wheelbase has six wires going in.......
One would say a steering wheel like this, should have a proper build and has that filter, right?

I will try to get a current measure now.

 

[Navigator]

Lol, it just now occurred to me I never measured current with the scope
I had to figure it out, because when I started, it said 8 amps.......that didn't seem right at all.
The probe was set
I think (hope!) I have the right setting now and it does seem more normal. Its 0,083 mA AC

So, that should be right, right?

 

[blekenbleu]

the power cable of the wheelbase has six wires going in

.. but that is for DC current between power supply and wheelbase.
Those DC lines presumably have substantial capacitors with very low impedance.

When I ground my rig, it goes away, only AC 0,78 V is left.

I do not know what is used for Fluke's ground reference;
properly grounding the rig should have reduced voltage to nearly 0.
I suppose that the cable between power supply and wall socket is 3 conductor,
and EMI filter would presumably be encapsulated in that power supply.

that should be right, right?

If there is indeed an EMI filter with capacitive voltage divider
and capacitors were exactly matched (very rare for capacitors),
then an ungrounded chassis voltage measurement with infinite impedance
would have been 115VAC in countries with 230VAC domestic supplies.
The Fluke 123 has 1 megOhm impedance rating;
dropping 115 to 8.55V suggests about 12.5 megOhm capacitor impedance,
ignoring phase shift, for 9.2 microAmpere leakage current. Your measurement is roughly 9x that,
but 0.78VAC measurement with grounded rig raises doubts about measurement conditions.

Regardless, 83 microAmperes is benign.

 

[Navigator]

Thats a good read, thank you!
I should have been more clear: the 0,78 VAC was there when I temporarily grounded my rig, sorry for that. That was off course a bit....mweh. Now, it is lower, zero.
And the current, I measured when it was ungrounded again (grounded would be useless) and that was when I got the 0,083 mA AC

 

[GeekyDeaks]

Sorry, missed some of this. You think it might just be RF getting shunted through the rig @blekenbleu ?

 

[blekenbleu]

it might just be RF getting shunted through the rig

Indeed it might; while 8.5V is more than I recall seeing from stray RF,
that Fluke 123 has 20mHz bandwidth, which exceeds my AC meters;
my oscilloscopes are not so portable, and I have no DD1 experience.
I did not see potentials so large when experimenting with indoor loop antennas
for RSP1A and a vector network analyzer, but it has much lower impedance;
perhaps I should go back thru my notes and calculate currents.

My AccuForce carries ground thru from wall outlet prong to motor case,
but I do not know whether DD1's in-line power module does;
other such bricks in my experience with EMI filtering molded into them and leakage current
back out to AC grounding prong (mostly for notebook PCs) galvanically isolate DC.

Reading reports of ground loops between DD1 rigs and other USB devices
led me to suppose that DD1 brick lacks galvanic isolation.

 

[Navigator]

Its getting more clear to me, I think
So, I shouldn't worry al that much?

I mean; the motherboard had a hissyfit, but that can come because of the pedals that were still mounted: 8 volts via the other usb trying to make ground, can do that I presume.

 

[GeekyDeaks]

I mean; the motherboard had a hissyfit, but that can come because of the pedals that were still mounted: 8 volts via the other usb trying to make ground, can do that I presume.

Well, I find it curious that you didn't see this noise when measuring ground against the output pin of the pots as that might have explained the fluttering. Only other thing I can think of is the noise is causing problems for the ADC, but it's all just guessing really.

At any rate, the power seems pretty low, so I'd probably not worry too much and just make a separate ground for the wheelbase if simply grounding the rig didn't completely solve it.

 

[RasmusP]

Im wondering if the fanatec pedals would show the same issues.
But I guess the connection to the wheelbase and and the rig would solve them?