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by isaac_alaska1
Sat Nov 14, 2015 4:11 am
Forum: BMS thread
Topic: Old BMS Software Thread
Replies: 600
Views: 288579

Re: Old BMS Software Thread

1.75 is expected with no comms. In order to fit the full cell range into 8 bits, and keep the necessary resolution, the slave subtracts 1.75V from the true cell reading before transmitting. The master then adds 1.75 to the reading before reporting it. So if there are no comms, it reads 0, and adds 1...
by isaac_alaska1
Thu Nov 12, 2015 9:56 pm
Forum: BMS thread
Topic: Old BMS Software Thread
Replies: 600
Views: 288579

Re: Old BMS Software Thread

I can't remember... Is there a clear alarms button? That might be the issue. I vaguely remember something like that. Also, to answer your previous question, you very definitely can use the arduino as a master. From what I remember nothing was written to use interrupts, so it's not too complicated to...
by isaac_alaska1
Thu Nov 12, 2015 8:57 pm
Forum: BMS thread
Topic: Old BMS Software Thread
Replies: 600
Views: 288579

Re: Old BMS Software Thread

If you have an oscilloscope, break it out :) if you dont, an old used Agilent off eBay is gonna be way more fun/easy to use than a brand new off-brand. I have a modern 4-channel tektronix, and I never use it because my antique 2-channel mono-color Agilent (just after they started using lcd instead o...
by isaac_alaska1
Mon Nov 09, 2015 6:10 pm
Forum: BMS thread
Topic: Old BMS Software Thread
Replies: 600
Views: 288579

Re: Old BMS Software Thread

I believe that only programs the slaves, and the master needs to match. I don't remember what happens if they don't. When I did it I had 48 slaves, so being able to program them all at once from the master interface was very nice, and reprogramming one master wasn't too big of a deal. Again, probabl...
by isaac_alaska1
Mon Nov 09, 2015 10:08 am
Forum: BMS thread
Topic: Old BMS Software Thread
Replies: 600
Views: 288579

Re: Old BMS Software Thread

You will need a pic programmer, probably someone on here can make the necessary code changes and recompile for you so you won't have to purchase any software. I haven't done any of this since 2012, but this is what I remember. These chips can be reprogrammed several thousand times, maybe more like a...
by isaac_alaska1
Fri Feb 22, 2013 5:31 am
Forum: BMS thread
Topic: Old BMS Hardware Thread
Replies: 613
Views: 301334

Re: Old BMS Hardware Thread

well that seems to be exactly the problem. i plugged in the working pics onto the "bad" slave board and all of a sudden it works. not sure why i didn't think of that before....i guess i was thinking 'well the software file is the same so the microcontroller will act identical" but cle...
by isaac_alaska1
Thu Feb 21, 2013 8:28 pm
Forum: BMS thread
Topic: Old BMS Hardware Thread
Replies: 613
Views: 301334

Re: Old BMS Hardware Thread

thanks greg, i'll get this in a couple hours, i'm in class right now.
by isaac_alaska1
Thu Feb 21, 2013 12:38 am
Forum: BMS thread
Topic: Old BMS Hardware Thread
Replies: 613
Views: 301334

Re: Old BMS Hardware Thread

the problem seems to be on the slave bus. the command being sent from the master board to the first slave is good, but the command being sent to the second slave is problematic. the width of the high and low pulses are not quite right. a high pulse (1) should be 104 us, and a low pulse should also b...
by isaac_alaska1
Mon Feb 18, 2013 6:56 am
Forum: BMS thread
Topic: Old BMS Hardware Thread
Replies: 613
Views: 301334

Re: Old BMS Hardware Thread

i have access to logic analyzers but i've never used one. i can learn though. what all signals do you want to see? all three slave bus commands and the master bus data?
by isaac_alaska1
Mon Feb 18, 2013 3:24 am
Forum: BMS thread
Topic: Old BMS Hardware Thread
Replies: 613
Views: 301334

Re: Old BMS Hardware Thread

*edit* i'm reading data on the slave bus at the third cell (commands to slave #3) and on the master bus. what i'm seeing is that on times when the voltage is reported correctly, slave three receives a command that looks like 110111111111110 (i'm estimating this based on time divisions of my scope) a...

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