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Old Sep 29, 2010, 08:53 AM
Go fast, turn hard
Tailslide UK's Avatar
Berkshire, England
Joined Aug 2006
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Question
Another Unilog connection thread

What a way to burn the momentous occasion of your 1,000th post!

In 35 years in the hobby, I have never encountered anything that has fought me at every step of the way as getting a Unilog to work. I am not knocking the product, as I am sure the problems are all of my own making. I have read the other "black wire" threads and need help working out if I have a black wire issue or a defective current sensor.

Background:

NEU motor
CC180 ESC on 1.56(beta)
Unilog on latest (September 2010) software (forget the #)
RPM sensor (pulse type connected between motor and esc)
Temp sensor (magentic on motor)
400 amp current sensor
4s 4200 lipos

Black wire is NOT connected to anything

Optical isolator between Unilog and Rx. Unilog (and one side of the opto) are being powered from the CC180 Bec. Rx and servos powered from onboard batt.

OK, I have the unilog set up to start recording after 15 seconds of power on and it does this. When running the motor, the temp and RPM are logging and giving good data. The current and voltage are logging, but read 0 (zero) all the time. At WOT, the voltage will go 0.1v negative and then return to 0.

How do I determine if this is a black wire issue or a bad current sensor? This set-up is identical to what other are running with no issues. The limiter function is enabled and set to 40% of pack capacity.

After reading the other ground loop threads, I am reluctant to connect the black wire. Again (I know you are ALL getting sick of me saying this) "any help greatly appreciated"

Cheers,
Paul

At least it is reaining too hard to maiden today anyway
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Old Sep 29, 2010, 11:40 AM
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dickw's Avatar
Luton, UK
Joined May 2006
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Paul
We all have problems from time to time, and we all had a few when we first used limiters, so no problems with answering your questions .

It should be possible to power the UniLog from the current sensor without the BEC. Disconnect the ESC signal lead from the UniLog to remove the BEC. Unplug the current sensor from the ESC and plug it into the battery +ve (that way you can't damage motor or ESC), then connect the black current sensor wire to the battery negative. The UniLog should now power up and also start recording the battery voltage. If it doesn't then there is definitely a problem with the current sensor. You could try removing and reconnecting the current sensor at the UniLog in case there is a dirty connector.

If it does work connected this way then perhaps one of the CC users would like to suggest the next step.

Dick
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Last edited by dickw; Sep 29, 2010 at 11:43 AM. Reason: Clarity
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Old Sep 29, 2010, 12:38 PM
Registered User
Scotland
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The Unilog and the connections to the CC180 are working correctly because the sensors are wirking. Careful about changing the wiring.

The problem is the connection from the current sensor to the Unilog. Unplug it and see if everything works the same. Then check if it is properly plugged in.

It must be the connection. The positive wire for the voltage and the two current sensor wires are just that, wires, no electronics, nothing to go wrong.

With the the plug from the current sensor disconnected use a voltmeter with the negative (black) connected to a black somewhere in the battery cicuit. Use a pin to to look at the voltages on the connector. You should get three reading the battery voltage 16V. If you connect the black/brown wire, or the black wire on the little connector to ground, the remaining connection should read 5V.

All that is from theory, I haven't tried it. Let us know what you find.
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Old Sep 29, 2010, 02:01 PM
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www.f5b.co.uk
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Old Sep 29, 2010, 02:06 PM
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Paul,
connect the spare black cable of the current sensor to the minus pole of the battery.
Otherwise the current sensor doesnt work.
Your Unilog is OK otherwise you couldnt log rpm. Just follow the instructions in the manual.
Best
Stephan
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Old Sep 29, 2010, 02:34 PM
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Sorry Schiwo1. Don't do that. There is a connection, supposedly, already via the really black wire in the little plug. A second connection can wreak havoc, ask Joe. OK with an opto isolated controller like the Schulze, not with the CC. Have you made the input connection modification described in www.F5B.co.uk?
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Old Sep 29, 2010, 03:34 PM
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Tailslide UK's Avatar
Berkshire, England
Joined Aug 2006
1,202 Posts
Thank you all for your replies.

The problem was in the plug from the current sensor to the Unilog. When none of the above tests made any difference, I started looking for wiring problems per the above post.

The red wire on the IDC (insulation displacement connector) had not cut through the insulation. Instead of cutting into the insulation, the serated edges had bent over when the unit was manufactured. A few minutes under the magnifier and getting out the TINY tools and presto! Sucess!

Static tests show 231 amps on a 3/4 charged 4s pack with rpms around 51K. A person could get addicted to that barking sound!

Everything is buttoned up and ready to fly tommorrow if the weather cooperates.

Do you tend to use 3v/cell cutt-off on your CC controllers? I noticed that the pack voltage dropped in a static test to about 11.75V. I assume that unloaded in the air and with a full charge on the Lipo this will stay just above 12V. All runs were about 2 second bursts with a minute or so between for things to cool.

Again, thank you all for your help in this build. It has had more than its share of just plain old bad luck. Fighting through problems is never that much fun, but when you are using new brands of equipment it helps to have some experienced people to ask. I really do appreicate it.

Cheers,
Paul
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Old Sep 29, 2010, 03:44 PM
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Tailslide UK's Avatar
Berkshire, England
Joined Aug 2006
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Quote:
Originally Posted by schiwo1 View Post
Paul,
connect the spare black cable of the current sensor to the minus pole of the battery.
Otherwise the current sensor doesnt work.
Your Unilog is OK otherwise you couldnt log rpm. Just follow the instructions in the manual.
Best
Stephan

Stephan,
Thank you for your reply. Unfortunately, I have to use the CC180 BEC to power the Unilog and the front side of the optical isolator. The unit is working now and I am back on track.

Cheers,
Paul
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Last edited by Tailslide UK; Sep 30, 2010 at 02:36 AM. Reason: Wrong Stephan
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Old Sep 29, 2010, 04:49 PM
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Paul, Schiwo = not Stephan Merz the designer of the Unilog. He is another Stephan.

George is correct, you don't wont to use the black/brownish wire from the current sensor on a P125/P180. The reason is that there is a little filter / resistor on the logic board that will blow up if you do this.

In general this mod is highly recommended; http://www.f5b.co.uk/?q=node/153

In particular, if you want to use the RPM sensor without burning your speed controller. So i recommend for tomorrow's flight you take the RPM sensor out until such time as you have done the above mod.

I am happy that you ask these questions but i would like to ask everybody to read what is written on the above linked website. It saves having to repeat stuff over and over again.

With regards to LVC settings. I hope you are joking, right?! You want to set it to 4V and use different means to not run the pack flat in flight such as a motor run timer or the limiting function of the device you have just installed. If you don't you risk the motor cutting out during launch and wrecking the model.

Joe
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Old Sep 29, 2010, 05:22 PM
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dickw's Avatar
Luton, UK
Joined May 2006
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Quote:
Originally Posted by Tailslide UK View Post
......Do you tend to use 3v/cell cutt-off on your CC controllers? I noticed that the pack voltage dropped in a static test to about 11.75V. I assume that unloaded in the air and with a full charge on the Lipo this will stay just above 12V........
Paul
I will back up what Joe said - set the LVC to the lowest level possible to make sure it never operates. I believe that is 4v total on the cc. The last thing you want is it operating at innapropriate moments.

At the sort of currents you are using now you are better off using timed motor runs and/or the UniLog limiter function. A few short flights and study of the data log will soon tell you what sort of motor run time you can expect.

Dick
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Old Sep 30, 2010, 02:35 AM
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Tailslide UK's Avatar
Berkshire, England
Joined Aug 2006
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Quote:
Originally Posted by jjmouris View Post
Paul, Schiwo = not Stephan Merz the designer of the Unilog. He is another Stephan.

George is correct, you don't wont to use the black/brownish wire from the current sensor on a P125/P180. The reason is that there is a little filter / resistor on the logic board that will blow up if you do this.

In general this mod is highly recommended; http://www.f5b.co.uk/?q=node/153

In particular, if you want to use the RPM sensor without burning your speed controller. So i recommend for tomorrow's flight you take the RPM sensor out until such time as you have done the above mod.

I am happy that you ask these questions but i would like to ask everybody to read what is written on the above linked website. It saves having to repeat stuff over and over again.

With regards to LVC settings. I hope you are joking, right?! You want to set it to 4V and use different means to not run the pack flat in flight such as a motor run timer or the limiting function of the device you have just installed. If you don't you risk the motor cutting out during launch and wrecking the model.

Joe
Joe,
Great info.

I should have stated that I had already done the filter by-pass mod on the CC180. It was covered well in the article you linked to. It has also been covered in multiple threads here on RCG. Not a jibe, but I do read as much of the information available that I can find before I post noob questions. In fact, most of my questions in this build have been answered this way.

As to the LVC, I guesss i can't stop thinking low power set-ups which is my comfort zone. I will change the LVC setting before I head out. I set my limiter to 40% of pack capacity for the first flight. Then I will download all the data and have a good study of it before I fly again.

My apologies Shiwo, I made a wrong assumption. When I saw Stephan from Germany, I thought you were from SM-Modellbau. Sorry if my reply caused offence. I will edit it.

Paul
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Old Sep 30, 2010, 04:25 AM
Needs to do 52 legs !!
jjmouris's Avatar
Verenigd Koninkrijk, Fareham
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Paul, no problem. Yes, i think better write that you have moved the black wire. Otherwise it will cause confusion.

When you say 40% pack capacity, i assume you are aware that W.min is not the same as Mah ?! Also if you set the limit below 1100W.min it will do the F5D thing where the motor comes back after some time, sounds good but if the limiter cuts at the end of a climb you won't notice it cut and then it will seem like the thing never cuts in! The 1750W.min we use in F5B results in around 50% battery capacity with a 500 gram Lipo pack. You could try 1300W.min wich is the F5F Energy limit if you wonna take it easy.

Good luck with the weather.
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Old Sep 30, 2010, 06:09 AM
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Tailslide UK's Avatar
Berkshire, England
Joined Aug 2006
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Quote:
Originally Posted by jjmouris View Post
Paul, no problem. Yes, i think better write that you have moved the black wire. Otherwise it will cause confusion.

When you say 40% pack capacity, i assume you are aware that W.min is not the same as Mah ?! Also if you set the limit below 1100W.min it will do the F5D thing where the motor comes back after some time, sounds good but if the limiter cuts at the end of a climb you won't notice it cut and then it will seem like the thing never cuts in! The 1750W.min we use in F5B results in around 50% battery capacity with a 500 gram Lipo pack. You could try 1300W.min wich is the F5F Energy limit if you wonna take it easy.

Good luck with the weather.
I set the limiter to 1600 w.min which should be ~45% of a 4200mAh pack. The numbers depend totally on what you guess the pack voltage to be while using up your watts. Until I see some hard data in flight, this should be on the safe side.

Paul
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Old Sep 30, 2010, 03:35 PM
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Sorry folks for my post. I was not aware of the specific behavior of CC controllers.
I am flying Schulze, Hacker and the Kontronik FAI ESC's w/o any problems with the Unilog. At least with those ESC's (all w/o BEC) there is nothing special to care about.
Best Stephan
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Old Jul 03, 2011, 06:18 PM
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la528it's Avatar
United States, WA, Redmond
Joined Dec 2007
2,146 Posts
I've searched and haven't found a clear answer to unilog on castle esc. Is it sufficient to wire the rx plug to the rx, an opticoupler to the signal lead, and the esc to the opti? I have an rx pack powering the rx and servos, so the castle bec would effectively power... Nothing.

Thanks ahead of time!

Ps black lead from shunt capped off
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