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INA260: how easy to damage?
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Please be positive and constructive with your questions and comments.

INA260: how easy to damage?

by furusato on Sun Nov 15, 2020 3:55 pm

Hi,

I've been using a INA260 to monitor the current on an OSEPP motor, and just received another for the other motor.

I haven't bridged VB so I'm using them high-side. I've wired both up, the first modified to be on I2C address 0x41 (rather than the default of 0x40). The new one on 0x40 doesn't show up on the bus when I use "i2cdetect -y 1". I then took it and connected it to a bare Pi Zero W and it seems it simply doesn't show up at all, likely burned out. I tried the bespoke wiring harness and the other INA260 on the Pi Zero W and that all worked fine, showing up on 0x41 as expected. I even bridged A1 on the broken unit to see if it showed up at 0x44, but no luck. This fault occurred on a known, functional robot but of course the INA260 is new wiring.

I'd not even ran the motors yet so I'm wondering if I've wired it up wrong. If I were to connect the Vin+ and Vin- backwards, would that damage the unit or simply not register any current?

I'm a bit mystified about what I've done wrong and don't want to plug another new one in before I sort out what happened.

Thanks very much!

furusato
 
Posts: 20
Joined: Tue Nov 05, 2019 7:42 pm

Re: INA260: how easy to damage?

by siddacious on Tue Nov 17, 2020 3:54 pm

Please post clear, in focus, well lit photos that show the wiring so we can get a better idea of what's going on.

siddacious
 
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Re: INA260: how easy to damage?

by furusato on Fri Nov 20, 2020 6:59 am

Hi, I'm afraid a photo probably won't be much help as the robot is fairly complicated and the wires extend through various levels of the robot, but I'll give this a try.

KR01 blog entry: Facilius Est Multa Facere Quam Diu

There's a 3mm delrin board on top of the chassis and another above that containing the Raspberry Pi, battery, sensors, etc.

The lower board contains the motor controller, 5v regulators, and the two INA260 boards. Basically, the INA260s are connected with four wires: Gnd, Vcc, SDA and SCL. One of them has its Alert pin connected to one of the Pi's GPIO pins. All pretty basic so far, just power and I2C.

The robot runs off of a Makita 18V power tool battery. The positive and negative wires of the battery are connected directly to the inner two terminals of the Thunderborg motor controller, which sends that on to the two pairs of motors (wired in parallel) via the outer two pairs of terminals.

The negative connections of the motors are connected directly to the M1- and M2- connections on the controller via black wires with red (port) and green (starboard) markings.

Each positive connection of the motor is connected through one of the INA260 board's Vin+ and Vin- terminal connections. These are the white wires with either red (port) or green (starboard) felt pen markings on them.

So the question is: if I got the wiring on the INA260s backwards (i.e., connected Vin+ and Vin- in reverse) would that be enough to blow a board?
Attachments
KR01-chassis-1240.jpg
photo of KR01 robot's lower board
KR01-chassis-1240.jpg (581.45 KiB) Viewed 82 times

furusato
 
Posts: 20
Joined: Tue Nov 05, 2019 7:42 pm

Re: INA260: how easy to damage?

by furusato on Sun Nov 22, 2020 12:32 am

I seem to have resolved whatever issue was plaguing the robot itself, basically I'd somehow fed a 5v line into a 3.3v one.

But there does remain that question I'm curious about: if one were to reverse the Vin+ and Vin- inputs on an INA260, would that damage the unit or simply not work? I've looked at the schematic for the sensor itself and it's not clear to me.

Thanks for any info.

furusato
 
Posts: 20
Joined: Tue Nov 05, 2019 7:42 pm

Re: INA260: how easy to damage?

by bludin on Mon Nov 23, 2020 10:29 am

The description in the datasheet says: The device is a bidirectional, low- or high-side, current-shunt monitor...

And under absolute maximum ratings, the datasheet list +/-15A for the maximum current, and -0.3V to 40V for (Vin+ + Vin-)/2, so I would say that having Vin+ and Vin- reversed should not cause any damage.
Cheers,
Beat

bludin
 
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Re: INA260: how easy to damage?

by furusato on Mon Nov 23, 2020 2:02 pm

Hi Beat,

Ahh, thanks -- I hadn't caught that, it's very helpful to know.

Cheers,

Murray

furusato
 
Posts: 20
Joined: Tue Nov 05, 2019 7:42 pm

Please be positive and constructive with your questions and comments.