Paul & Sabrina's cheap DIY 144v motor controller

[magicsmoke]

Hi Squiggles, I see you made the same mistake I made at first (5V / 10K + 1K).
It's actually 0.455mA!!
When I ran the numbers I thought as well as developing a wonderful controller, the group had also invented a magical current vanisher too!

Rob

[MPaulHolmes]

Thanks you guys for fixing my mistake! R12 is after R11. I'm such a whippersnapper! Yes, it is good to assume they are set to output. Man, that has been a problem for maybe 1.5 months. Holy cow! "Oh no! It's latching up!" Idiot!@! aaaaaaaaaaaaaahhhhhhhhhhhhh!!!

I'm putting together a basic serial output thing right now for tuning the PI loop. I'm really looking forward to seeing what sort of data comes from that.

[magicsmoke]

Hi Paul, as an aside. The HIN202CP rs232 tx/rx that you've specced isn't lead free.
It might be worthwile checking the entire BOM to make sure.
I'm concerned that disgruntled controller manufacturers might point the finger and effectively block export of any kit sales, certainly to Europe anyway!

cheers Rob

[MPaulHolmes]

Lead never hurt anyone, well except for lead bullets and poisonous paint and poison water and birth defects and stuff like that.

How do you guys fish over there without sinkers??!

[nubie]

Originally Posted by MPaulHolmes

Lead never hurt anyone, well except for lead bullets and poisonous paint and poison water and birth defects and stuff like that.

How do you guys fish over there without sinkers??!

Ha!

But seriously, the EU is big on not letting Chinese kids die from open lead fires caused by old equipment recycling, the solution? No lead in old equipment.

Probably best to spec it without, or fail to include it and label the kit "ROHS RS-232 free"

I am glad to see it coming along, I hope that guy with the new controller has a chance to test it

[magicsmoke]

yes yes very drole, but as it happens ..

No fishing weights made of lead may be used except those of 0.06 grams or less and those of more than 28.35 grams.
We haven't got any fish left anyway, the French and Russians have nicked them all!

Sticking to the controller though, the 'Pb free' thing of course relates to the soldering as well, a real pain trying to achieve a nice joint on heat hungry components.

[MPaulHolmes]

I'm getting 4000 samples of the current per second through the serial port at 19.2 kbps. I'm just sending a raw number that is from 0 to 213 (about), where 0 means 0 amps, and 213 means 500 amps (about). I'm sending no CR or LF. The truly awesome "realterm" program that I'm using adds spaces between the data, and then I can put it in Excel or something and see some graphs. Oh ya! A step response with maybe 10000 data points is going to be nice! I thought 19.2 was going to be too slow! haha!

I also changed the program to make the current reading more exact. Before it was off by about 7 amps. I was using vRef = 2.5v, but the datasheet showed that there was a bit of variation possible, so I did a sample of the current at 0 amps (16 reads) and averaged them, which now shows 0 amps right now on the serial terminal (before it said 7 amps), which it IS! I don't have that dang thing hooked up to a car! There's no current going through it!

I want to make a database of motors, and the optimal P and I for each motor, given a persons preference for how the throttle should feel. As Adam was saying, various "profiles"! ya!

Here are a couple pictures of the setup in the room (I also added 32 other pictures of Ben's assembly. Some of it wasn't photographed because I ran out of stupid batteries!!!!!!!!! makes me mad):

Ben's Open Revolt Cougar Controller, battery for powering it, stk500, oscilloscope, serial port plug thing.


What's this? Motor current being blasted to the screen at 4000 samples per second? I think it is! ya!

[blowncurtice]

I have just finished a new Australian Parts list and cost. does not include the two boards, I am hoping that those will be organised in the US.
John

[blackpanther-st]

Originally Posted by MPaulHolmes

I disabled all pull up resistors (Thanks, JayC), and the dang blasted thing still didn't work! monkey poo! I thought that would be it for sure! But then I added a temporary pull down resistor from PIN 5 of U5B to Ground (is that redundant? hehe), and it seems to work! Maybe I'll just solder a 2 or 3k resistor there and test that monkeypoo out!

just read this and haven't read forward yet, so maybe you have it now, but this sounds to me like you had an unexpected load / resistance imbalance. The added resistor may be fixing the problem, but I would look further to find the cause of the imbalance; you may just have to change the value of an existing pull up of pull down.

[blackpanther-st]

I just read up to here and I see you got the over current latch up issue fixed, so I guess disregard my last.

As far as current sensors go, I wish there was a reasonably priced hall sensor for 1000A so far all I can find is like $100. I am probably going to read of of my shunt instead, but at 75mv full scale, that is going to be difficult to get an accurate trip point set. Any recommendations for either option?