Grey Jaguar No Power Out
 

We have a Grey jaguar that appears to be in normal working order except it has no power coming through the output...

The device is wired properly. The device's indicator is responding appropriately to commands...we are getting full red and full green led feedback.

We just don't get any juice to the output. Is this as simple as "the jaguar is broken?"

Thanks for any insight.

Re: Grey Jaguar No Power Out
 

I'm guessing you mean your motor doesn't move. I am also assuming you are using a DC 12 volt motor. If I am wrong tell me.

First thing to do is check the output with a voltmeter and see if you get any power through.

If that comes up flat I would check if the code thinks that out put is a victor. That has caused weird results for us.

Re: Grey Jaguar No Power Out
 

If the limit switch jumpers were missing, then you'd also get those symptoms - red/green LED but no power out.

Re: Grey Jaguar No Power Out
 

I checked that first. ;) Also, this isn't an FRC application.....so there should be no mystery code issues.

The limit switch jumpers are in place.

Re: Grey Jaguar No Power Out
 

Are they in the right direction (vertical)? I remember someone on our team once flipped them horizontally and it did something like that

Re: Grey Jaguar No Power Out
 

That isn't entirely accurate. When the limit switch input is open (no jumper), you will get a slow blink red indication on the LED if you try and drive the Jaguar in the direction with the open limit switch.

Are you using PWM or CAN to communicate with the Jaguar?
Is this a brand new, out of the box Jaguar?
Have you noticed any ESD (Electro Static Discharge) events?
Have you unscrewed the screw terminals completely (aka using ring terminals)?
Metal shavings in the case?

-David

Re: Grey Jaguar No Power Out
 

We are using PWM.

Not new.

No ESD.

We are however using ring terminals....I did notice in the manual that it says these shouldn't be removed completely. It is possible that there are metal shavings in the device.

Re: Grey Jaguar No Power Out
 

Tony,
There is a possibility that there is shavings in the device. However, if it is an older jag, it might have succumbed to the dreaded FET driver failure. It is also possible that the current sense resistor has unsoldered itself. This leaves the low side of the output stages open. I do not know if the firmware checks for that condition but I have opened a few Jags where this has occurred. As others have hinted, be sure that the terminals have been correctly crimped by checking the output of the Jag with a voltmeter. The resistor lives near the negative input terminal (upper left when viewed from above with the jumpers toward you) and is the largest surface mount resistor in that area.

Re: Grey Jaguar No Power Out
 

I left this unresolved for now......I grabbed another Jaguar in the meantime.

I suspect that I will find shavings inside at some point. :(

Thanks for the help. I was able to get the machine up and running with no problems.

Re: Grey Jaguar No Power Out
 

Anthony, once upon a time the folks who make the Jaguars were excepting returns for troubleshooting. You may want to contact them (you can find them in a more than a couple threads) and see if they're still taking return / swaps. You might get lucky and get it replaced for free.

Re: Grey Jaguar No Power Out
 

As the old saying goes: "If you don't ask the question, the answer is NO"

Re: Grey Jaguar No Power Out
 

Good thinking....I'll ask.

Though I read in the manual explicit instructions not to completely remove the terminal screws. :(

I see they changed that with the Black Jaguars. :ahh:

Re: Grey Jaguar No Power Out
 

My team was having this exact same problem, thanks for all the possible problems to try. We ended up getting another Jag anyway, but if we can fix our broken one then at least we have a backup.
I know we've unscrewed the terminal screws several times, so we could have shavings. I don't think it's the program or jumpers, I've checked those, and I think I would have noticed if the current sense circuit was unsoldered when we opened the Jag. I saw something in the Jag manual about calibrating the PWM signal, so I might try that. It could also be one of the MOSFETs. Anyone know a way of testing if any are blown and/or how to replace a broken one?

Re: Grey Jaguar No Power Out
 

Daniel,
The current sense resistor might not grab your attention if is missing. This was the case in some of the devices I inspected. Generally, when a FET goes bad, it leaves a burned area around it. The plastic FET retainer/insulator will be melted and there will be black marks on the board as well as burned circuit board traces. If the FET is open, you can measure with a VOM. Use the diode test position on your meter if it has one. In general with a failed FET gate driver, there is no visual damage. However, on several I have examined, the FEET driver chip had blown apart one corner and left a crated on the board.

Re: Grey Jaguar No Power Out
 

I can't see that any of these problems are what's wrong with our Jag. The only visible thing I see that's different with the diagram in the manual is an extra resistor connecting R25 and R24, right under the current sense resistor. All our Jags seems to have it. The color bands go gold, yellow, purple, yellow. I realized also that the one we have that isn't working is one of the four we got in the rookie kit last year but have never used until now, so it's actually never worked, but all the others have. Is that resistor supposed to be there?

Re: Grey Jaguar No Power Out
 

Daniel,
The resistor is read the other way indicating it is a 470K (yellow, violet, yellow) while the gold band indicates 5%. In the schematic it is the bias resistor for the current sense amp, R43. This resistor centers the opamp operating voltage so that it varies around a quiescent 3.3v/2. When you try to use your Jag what is the color of the LED telling you?

Re: Grey Jaguar No Power Out
 

The lights read as if the Jag were operating normally: medium flashing green when forward, solid orange when stopped, and medium flashing red when backward.
Actually, while typing that I thought of something! The Jags are supposed to show solid green when fully forward and solid red when fully backward, but even when I push the joystick all the way, it never goes solid. When we tested the voltage coming out of the Jag, we just got negligible voltage and assumed it was nothing, but maybe for some reason the speeds are getting scaled down by 50 or something. I'll try to look into why that would be.
That seems the most likely reason for our trouble now, since I couldn't find anything else wrong with the Jag. The manual said: "To accommodate variation in the timing of the supplied signal, the MDL-BDC has a calibrate feature that sets new values for full-forward, full-reverse, and points in between. Calibration is typically only required in applications where the PWM source has uncertainties due to analog radio links or other variables. Direct digital sources are unlikely to require calibration." This might be one of those "unlikely" times.
So that might be it. Al least it's now the primary suspect, and secondary would be the code.

Re: Grey Jaguar No Power Out
 

If you are using a cRIO with WPILib to control your Jag over PWM, you should not need to calibrate it. They were designed to operate together out of the box. Do make sure that you haven't told WPILib that you are using a Victor instead of a Jaguar, though.

Re: Grey Jaguar No Power Out
 

Daniel,
The lights indicate that you are not going to full throttle in each direction but that is usually the case. If the control fault is not software related, Jag calibration will match your controller to the full output of your joysticks.
If you are only testing the output of the Jag with a voltmeter, remember that the Jag output switching frequency is 15kHz which is way above the frequency limits for many voltmeters. They are also not intended to read PWM, square wave signals. The Victors are 150 Hz which is in the range for most meters but are still not accurate due to the square wave output of motor controllers.

Re: Grey Jaguar No Power Out
 

I would think an analog voltmeter on the "DC" setting would do a reasonable job of measuring the effective DC-equivalent voltage of the Jag's PWM output.

Haven't actually tried it though. Anybody got data ?

Re: Grey Jaguar No Power Out
 

You mean a Simpson 360 type meter? At best it might give you average readings for most of the higher throttle values. AT 50% or less, I don't think you could depend on it to give you any meaningful info other than the polarity and presence. The meter movement varies so much from manufacturer to manufacturer that I don't think you can make a blanket statement.

Re: Grey Jaguar No Power Out
 

I mean an analog voltmeter, with coil movement and a needle pointer.

Any cheap $10 one would do, set to read DC.

By "effective DC-equivalent voltage" in this context I mean the following:

- When the Jag is being commanded to output 100% voltage, the meter would read 12V at the Jag's output.

- When the Jag is being commanded to output 50% voltage, the meter would read 6V at the Jag's output.

- When the Jag is being commanded to output 0% voltage, the meter would read 0V at the Jag's output.

- When the Jag is being commanded to output -50% voltage, the meter would read -6V at the Jag's output.

- When the Jag is being commanded to output -100% voltage, the meter would read -12V at the Jag's output.

etc


Haven't actually tried it though. Anybody got data ?

Re: Grey Jaguar No Power Out
 

I tested both an analog and a digital multimeter set to DC and got identical responses in the range of 0-5.5v for zero to full throttle on a jag output.

P.S.
I'm a little slow, but I awoke in the middle of the night to the realization that my measurement mistake was because the battery had been drawn low by the motor load probably coupled with a low battery.
The battery I used was drawn down to 7.5v, so apparently ~2v might get dropped by measuring with these type of multimeters.
I'll check again with a fully charged battery and without a motor load when the real morning comes.

Re: Grey Jaguar No Power Out
 

Most interesting. Did you have a motor connected or no ?


Also, at full throttle isn't the Jag's output waveform supposed to be essentially a flat-line 100% 12V ?

Re: Grey Jaguar No Power Out
 

I tested with a stronger battery and it had the same 2v drop through the jag showing on both analog and digital meters.
Jag goes solid green for forward.
I'll put a scope on it later to see what's happening to both the power output and to confirm the PWM input signal is at full.
I took the load off for this second test, so the Jag had nothing connected this time.

The original test was done on a competition robot. I moved the second test to a stand-alone cRIO/Jag (quieter that way...).

Re: Grey Jaguar No Power Out
 

Mark,
I know I am asking a lot, but when you set the test up with motors, can you evaluate with a CIM connected and window motor connected?

Re: Grey Jaguar No Power Out
 

I can add tests with both CIM & window motors.

My scope has a problem so I have to use the one in the robotics lab. I think the one in our lab is a 20MHz model.
I got lazy and brought stuff home where I thought I had a better scope...

Both types (analog/digital) of multimeters do measure Victor full power correctly. I even tested by alternately telling the software it was a Victor/Jaguar just for fun.

Re: Grey Jaguar No Power Out
 

Are you saying you don't see the 2V drop with the Victor, but you do still see it with the Jag? If so, could you put the scope on the Jag's PWM input and see what pulse width is being commanded at full throttle ?

Re: Grey Jaguar No Power Out
 

Fixed my scope - broken ground reference wire.

Looks like the PWM signal is correct on both the Victor (smaller range) and Jaguar (larger range) settings.
The solid green/red light on the Jag does indicate full power is being ordered via PWM.

The Jag just reads 2v under at max while the victor reading equals max voltage.

This is all without any load. I created button controls to order full power, in addition to a throttle test.

I'll pick up motors tomorrow for further testing.

Re: Grey Jaguar No Power Out
 

May I echo back to you what I think I hear you saying, so you can correct any misunderstandings?

- you fixed your scope (yea!)

- you scoped the Jag's input PWM and it had a 2.33ms pulse width at full throttle?

- you scoped the PWM output from the Jag while commanding full throttle and you saw a 100% duty cycle on the output and yet the voltage measured by your meters was 2V lower than the supply???

Re: Grey Jaguar No Power Out
 

Mark,

Are you looking at the servo signal into the Jag, the waveform on the motor outputs, or both?

I'm curious as to what the waveform on the motor output looks like. Is the peak voltage out of the Jaguar (on the scope) 2V less than the battery voltage?

Can you post pictures of the scope traces?

-David

Re: Grey Jaguar No Power Out
 

I mean it's weirder than I thought it'd be.

The bottom line seems to be that the Jag at 100% provides 2v less power than the Victor.

It has nothing to do with the multimeters, they work fine. They might under report the power based on the output waveforms, but the results are certainly usable and close enough for the average FRC team.
The PWM signals have the appropriate ranges for each device. They also are fine.

The Victor and Jag (via scope) both have the expected designed output waveforms at anything other than full power.
The Jag's is a lot more vigorous of course.

The Jag does something funny.
The power output waveform begins at lowest duty cycle by oscillating in the range, say ~2v (rather than 0v as expected) to battery voltage. As power is increased, the lower bound rises towards the upper bound which remains steady at battery voltage.
At ~90% the upper bound of the waveform begins collapsing as the last 10% is transistioned. The upper limit of the waveform begins to drop to meet the still rising lower bound. Although the lower bound stops 2v down and waits for the upper bound to fully collapse to meet it.
Eventually, at 100% duty cycle they meet at a point 2v less than the battery voltage.
So peak voltage on the Jag output is 2v less than the battery voltage.

----
My scope is an old 40MHz Kenwood that doesn't get used a lot. The multimeters are Craftsman sale specials.
Certainly I'd like someone else to repeat the results before saying I didn't make some measurement mistake.

Re: Grey Jaguar No Power Out
 

For the record, did you observe this same behavior on more than one Jag? And, are we talking Black or Tan Jags here ?

Re: Grey Jaguar No Power Out
 

Good point.

The odd behavior was on a tan jag.

I just tested a black jag and it did not have the problem.
The multimeters work fine on the Black Jag too.

Re: Grey Jaguar No Power Out
 

Weird indeed.

Did you measure the battery voltage when the Jaguar was at full output, to make sure something wasn't loading it down?

The rising of the low-level voltage is probably happening because there's no load, but it'll be a good idea to check that.

Re: Grey Jaguar No Power Out
 

I monitored the battery voltage throughout the tests and it didn't drop.
I will try again with motor loads tomorrow since I've come this far.

I don't know if the tan jags have different rev levels, so that originals have a problem but later revisions do not.

Re: Grey Jaguar No Power Out
 

Mark,
I am guessing you are still measuring open circuit on the controllers. The FAN5109 gate driver used in the grey Jags has "adaptive gate drive" and so maybe responding to the lack of a load. The bootstrap cap might be having some effect as well and there is feedback to the micro from each of the bootstrap circuits. (VbootA and VbootB) Are you hanging the scope across the output of the controller or are you connecting the probe ground to the negative power supply input and then connecting the probe to one of the output terminals?

Re: Grey Jaguar No Power Out
 

Yes, these measurements were still taken with no load on the speed controller outputs. I'll apply loads tomorrow to see what that looks like.

Usually I ran with the probe ground to the negative power supply input because I was hopping around testing both the Victor and Jag speed controllers as well as the PWM inputs to both at various times.
But I also tested with the probe ground to one of the output terminals and saw no difference.

The multimeters were applied just across the speed controller outputs.

P.S.
The other caveat is that I could by chance be working with a damaged tan jag. I'll test with others to see if it's a broad issue.
Update: Nope, I tested three tan/gray jaguars and they all exhibited the same odd response. They were never-been-used 2010 KOP Jags.

Re: Grey Jaguar No Power Out
 

^Reported

Re: Grey Jaguar No Power Out
 

I tested with a globe motor load and the oddity disappears, so the odd collapsing waveform and the 2v drop seems to just be a characteristic of the adaptive gate Al brought up and the lack of a load as Alan suggested. It shouldn't affect normal operation.
There was a .15v drop through the Jag at 100%, but my battery is down a bit so that's not a full measurement.

The gray/tan jag gives full power at 100% with a load, and 2v less without a load.

With a load the waveform is the typical duty cycle switching between 0 and battery voltage for increasingly longer times as the throttle changes.

The CIM and the window motors show a cleaner 100% than the globe motor for some reason. Up to 100% everything about the power output waveform is identical. At 100% I see the periodic tiny drop to 0v on the CIM and Window motors, but for the globe the scope displays a messier plot.
The CIM also drew the battery down a bit more than the others of course.

Re: Grey Jaguar No Power Out
 

Did you observe this behavior in both the Tan and Black Jags, or the Tan Jag only?

I ask because Gdeaver reported in an earlier post that the Black Jags use locked anti-phase switching.

Re: Grey Jaguar No Power Out
 

The black Jag behaves straight-forward that way with or without a load.
A long time at 0v/short time at max volts, progressively shorter time spent at 0v, until it's full time at max volts.

The top end dips only in response to dropping battery voltage as the load draws more power.

Re: Grey Jaguar No Power Out
 

So this whole thread just the result of measurement error?

Put simply, it would be physically impossible for a Jaguar (or a Victor) to have an actual 2V drop while driving a motor and not be on fire: It is WAY too much heat to dissipate.

Re: Grey Jaguar No Power Out
 

80 watts IS a lot, isn't it?
I wonder why infineon claims each power transistor can dissipate 100 Watts?

Anyways, I would appreciate getting back to the original topic. I recently obtained a Jaguar that has this problem. (I'm not sure what was done to it.)
The only damage I see is around the traces on ONE of the MOSFETs. However, I get no voltage both in Forward and Reverse.

Re: Grey Jaguar No Power Out
 

I think the discussion was fruitful, and produced a useful bit of knowledge:

An inexpensive multimeter (affordable by any team), set to read DC volts, should read the same voltage at the power inputs and the motor outputs of a Jaguar (either tan or black, or a Victor) when the Jag (or Vic) is being commanded full throttle and has a motor connected.

This knowledge is useful for helping teams to diagnose/troubleshoot Jag/Vic problems. Thanks Mark for the effort you put into running the tests.

Re: Grey Jaguar No Power Out
 

That spec only accounts for the junction to case thermal resistance and assumes a perfect heatsink with infinite mass at 25C. Power MOSFET specs are actually pretty funny when you look into the assumptions made.



I'm still confused as to what is going on. How is this different than the ESD issue?

Re: Grey Jaguar No Power Out
 

How is the "no power out" different from the ESD issue?
Did I miss something?

In order for ESD to be a problem, wouldn't the case have to be opened up. You're saying the case was opened up while the Jaguar was still functional? Why would someone do that?

Or is it something else entirely?

Re: Grey Jaguar No Power Out
 

Marshal,
The ESD issue didn't need the case to be open. During the 2009 game, the regolith especially in ice arenas produced some rather extensive static lightning strikes for robots and field. Some of these events punched through the case or traveled along the wiring and took out some components. The early Jags also had an issue with the FET gate drivers that would self destruct and usually caused a single direction failure.

Re: Grey Jaguar No Power Out
 

Does that mean I can return it for replacement?

Re: Grey Jaguar No Power Out
 

I would recommend that you read the Jaguar Failure Analysis (FA) report, and then at least attempt an RMA. Both are linked from the luminary micro jaguar FRC site. Your Jaguar is probably out of warranty, but it doesn't hurt to try, and at least lets TI know the extent of the problems.