Master Board Version 3

Threads relating to the BMS system begun by Peter Perkins

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Master Board Version 3

Postby GregsGarage » Mon Jul 12, 2010 5:54 am

Peter started a wish list for version 3 of the Master. So I have copied it and started a new thread for it here. At the moment this is just a feature request for the next version of the master display board.

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I would ilke to start a list of hardware features for bms master board v3. Please quote this post and add your stuff at the bottom of the post. I'll start it off. The board will have all the features of V2 in addition to the below list.

1) Picbasic pro based 16F886 Master Chip with icsp
2) Picbasic pro based 12F683 Watchdog chip with icsp
3) Tellymate Video chip 38x25 Display with icsp
4) I2C Eeprom chip 64kbyte

5) Auto power off option once charging complete. BMS powers down after charge end. Save aux battery power. Possibly power BMS from main pack? Once BMS has turned itself off can't restart without operator input.

6) Two seperate charging relay outputs to control a home made two stage charger using 48v open frame power supplies.

7) 19200 baud in/out ports/feature for the home made controller interface. Greg

8) Possible delayed charge start to allow use of off peak electricity. Not sure hiw that will work with option 5

9) Remote display tx port

10) Slave bus to loop back to master board. This will allow confirmation that all slaves have received the proper commands.

11) ?
Greg Fordyce

Daewoo Matiz
http://www.evalbum.com/4191

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Re: Master Board Version 3

Postby martinwinlow » Tue Aug 24, 2010 10:29 pm

My wish-list:-
1/ RPM sensor input as well as speed sensor (same type) or software configurable choice from the 2 - with option to limit controller in event of motor over-speed
2/ USB serial data output for computer based loging and/or display
3/ ...

MW
Regards, Martin Winlow
Herts, UK
http://www.evalbum.com/2092
www.winlow.co.uk

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Re: Master Board Version 3

Postby retepsnikrep » Thu Sep 23, 2010 7:28 am

martinwinlow wrote:2/ USB serial data output for computer based loging and/or display


That is available using a simple serial to USB lead. Do we need two way comms?


New feature

Digital 5k pot output control for cheap charger voltage control
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: Master Board Version 3

Postby martinwinlow » Thu Sep 23, 2010 5:51 pm

Peter, Yes if, for example, you want to set up a system of timed charging to, say, take advantage of off-peak electricity controlled by the carputer... and I suspect there are many other reasons why 2-way comms would be useful. MW.
Regards, Martin Winlow
Herts, UK
http://www.evalbum.com/2092
www.winlow.co.uk

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Re: Master Board Version 3

Postby GregsGarage » Fri Sep 24, 2010 9:41 pm

martinwinlow wrote:... and I suspect there are many other reasons why 2-way comms would be useful. MW.

How about a bootloader as an alternative to using a ICSP header for programming. We don't need to do this, but can make the required pins availble for serial comms if we want to at a later date. Found this link. http://www.etc.ugal.ro/cchiculita/software/picbootloader.htm
Greg Fordyce

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Re: Master Board Version 3

Postby retepsnikrep » Sat Sep 25, 2010 4:28 am

I looked at a bootloader but discounted the idea for a few reasons.

1) We loose a bit of code space. The Master program is pretty big.
2) The bootloader can't update the eeprom or pic config bits.
3) It doesnt work for the 12F683 so we have to have icsp for that.

I wanted a standard approach where a simple cheap USB programmer can be used to upgrade the two main chips. Can't get much simpler than 5 sil pins or pads on the board.

I realise the Tellymate video chip adds another dimension and a ISP port specific for that may be reqd. But hopefully updates to the tellymate should be very unusual and perhaps do not justify ISP on the board.
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: Master Board Version 3

Postby retepsnikrep » Sat Oct 02, 2010 5:49 am

OK here is a rough jpg schematic for V3 1.5mb http://www.solarvan.co.uk/bms/MasterV3_011010.jpg

We still have four Master I/O pins free (six if we also use the ICSP pins)

Pins C6 & C7 can be dedicated to serial I/O and use the hardware USART, so we can get high speed, easilly enough to communicate with Gregs controller.

I have reallocated most other pins, especially those that have hardware links, like the two pic PWM pins are now connected to the charger/controller control optos!

I don't propose to add crystal or resonator support. IMHO the internal resonator 8mhz is fine for this application.
I have added two way comms between Master and Watchdog chips.
I have removed analog temp sensor support as we now have the I2C ones working and can have as many as we want. With the new tellymate screen space we can have lots more info on the main screen. 8)
I have added a motor or engine Rpm input.
I have added a slave command loopback opto isolated input.

Francisco i have noted you idea about moving to another chip, but I don't want to go through the steep learning curve for yet another chip, I don't fully understand this one yet :lol:

I have simplified the layout somewhat and improved the master bus noise rejection. I have also removed the varistors.

Comments?
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.

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Re: Master Board Version 3

Postby GregsGarage » Sat Oct 02, 2010 12:22 pm

Just had a quick look at the schematic. I don't see a connection between the tellymate and the master. The tellymate also supports 2 way communications, that is it can report the contents of a screen location, kind of a bit of extra memory space. I don't know if it would be useful but maybe consider a connection for this to the master. It could have a jumper if we want to use it for something else.
Greg Fordyce

Daewoo Matiz
http://www.evalbum.com/4191

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Feature request

Postby GregsGarage » Wed Oct 06, 2010 10:32 pm

I have a feature request for V3. It's not really a bms feature, more of a electric vehicle feature. It has to do with the vacuum pump for my brakes. I have a nice little pump from a VW, about the size of a soda can but it doesn't have a vacuum switch. On the Volvo I just powered it from the brake lights, a simple but effective solution. I want to do something a bit more clever though. The Matiz has a manifold pressure sensor mounted to the bulkhead. This can be connected to the hose between the brake servo and pump. It is a 3 wire sensor +5v, GND and signal. I could use the master to read the signal wire with one of the spare analogue temp pins and control the pump from another spare pin. A few lines of code to check the value of the signal wire each time through the loop would be all that is required.

Now this is quite specific to my needs, but other people may have other specific needs, so my request is not for a vacuum pump control circuit, but a general prototyping area on the board. This could have +5v, +12v and GND rails, a grid for mounting any required components, resistors, caps, transistors, optos, etc., and a connection header. What do you think?
Greg Fordyce

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http://www.evalbum.com/4191

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Re: Master Board Version 3

Postby retepsnikrep » Thu Oct 07, 2010 6:58 am

Greg

I have now used up all the I/O on the master board. We already have a few extra i/o now inc dedicated Tx/Rx for your controller, Rx from watchdodg for one second pulses, rpm input etc, Rx/Tx with laptop for spreadsheet. I did not include the return from the tellymate as i can't see any need. It's a dum peripheral.

If we are going to sacrifice something for your vacum pump then i would have said watchdog second pulses and rx from laptop so we can still log data to it but it can't send anything back.

Personally i think a seperate little board with a simple 12F683 looking after your pump is the best idea. Unless you want the main BMS display to show vacum level etc :?

Here is a newer version of master schematic. There are a few errors duplicate components labels etc but it's nearly there. I'm still pondering on the best config for the master bus and slave echo bus input, may do away with the led and put a 1n4148 in there and a 5v zener across input to prevent pulses above 5v getting in. We have to be sure voltage swings are enough to ensure solid logic 0 and 1 are received/detected by pic.

www.solarvan.co.uk/bms/MasterV3_071010.jpg
Regards Peter

Two MK1 Honda Insight's. One running 20ah A123 Lithium pack. One 8ah BetterBattery Nimh pack.
One HCH1 Civic Hybrid running 60ah A123 Lithium pack.


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