Re: SV: SSRs, relays, speed controls

["flier" <FLIER-at-sbcglobal.net>]

Hi Bjorn,

I ran across this the other day.  The interesting 
thing is I don't think Bob's code even uses the PWM 
modules of the '876.  I think it's done with inline 
code and timed loops but I haven't had a chance to 
look it over good.

Thanks,

Ted


--- Original Message ---
From: =?iso-8859-1?Q?Bj=F6rn_Wallentinus?= 
<bjorn.wallentinus-at-abc.se>
To: <tanks-at-rctankcombat.com>
Subject: SV: SSRs, relays, speed controls

>Don't know if this will help you but there is code 
for the 876 on this pa=
>ge
>http://www.bobblick.com/techref/projects/sv2hb/sv2hb.
html
>
>Regards Bj=F6rn Wallentinus
>Stockholm, Sweden
>
>> -----Ursprungligt meddelande-----
>> Fr=E5n: tanks-admin-at-rctankcombat.com
>> [mailto:tanks-admin-at-rctankcombat.com]F=F6r flier
>> Skickat: den 4 mars 2004 02:43
>> Till: tanks-at-rctankcombat.com; 
tanks-at-rctankcombat.com
>> =C4mne: Re: SSRs, relays, speed controls
>>
>>
>> Ah ha!  Great.  I have six of the D1D40 Crydom SSRs
>> on the way but was trying to figure a cheaper
>> solution since those things actually sell for 50$ 
or
>> more each.  Using two makes the controller more
>> reasonable if someone had to buy the relays
>> wholesale.  Plus, I'll have relays on hand for 
THREE
>> tanks now  ;^)
>>
>> Hey, sign me up for some code when you can.  I
>> already have some '876s on the way.  I think I'm
>> going to try some of those cheap 40A 12v spdt auto
>> security relays first so the PCB won't be necessary
>> yet.  At less than $2 a pop I can see how they work
>> and go the other route if they crap out.
>>
>> --- Original Message ---
>> From: Joe Sommer <anvilus9-at-adelphia.net>
>> To: tanks-at-rctankcombat.com
>> Subject: Re: SSRs, relays, speed controls
>>
>> >
>> >Ted,
>> >
>> >At 05:09 PM 3/3/2004 -0500, you wrote:
>> >>To keep costs down (given that the applicable
>> >>ucontroller programming would have to be done),
>> >>couldn't one implement full two motor reversable
>> >>speed control using only two SSRs and four 
regular
>> >>SPDT relays?  Use the SSRs to provide the high
>> >>current PWM and the SPDT relays to do the H-
bridge
>> >>switching?  Specifically, use a PIC 16F876 to 
mix 4
>> >>outputs driving the relay switching and the two 
PWM
>> >>modules driving the SSRs...
>> >
>> >Preliminary coding for this is done except for
>> >exact pin assignments.  I already merged
>> >the code for my full bridge SSR with the code for
>> >Steve Tyng's relay driver board.  The code fits
>> easily
>> >in the 876.
>> >
>> >The board will essentially look like the Dual 
Motor
>> Relay
>> >Mixer shown at   www.anvilus.com  but will 
require a
>> little
>> >more PCB area for the 876 versus the 628 CPU, and
>> >for extra connecters.
>> >
>> >7 or 8 position power connecter
>> >left B+, left B-, left forward, left reverse
>> >right B+, right B-, right forward, right reverse
>> >(motors can share the same B-)
>> >
>> >3 or 4 position TTL connecter for PWM output
>> >left PWM, left GND
>> >right PWM, right GND
>> >(outputs can share same GND connecter)
>> >
>> >2 position connecter for 12 VDC relay coil power
>> >
>> >Each motor will require its own B+ connection.
>> >If you simply wish to use full speed
>> forward/off/reverse,
>> >you will connect the battery directly to the B+.
>> >If you wish to use PWM, you will connect the
>> >battery to the top side of the SSR and connect
>> >the low side of the SSR to B+.
>> >
>> >I can send a draft of the PCB layout if you wish.
>> >It has four onboard SPDT relays.
>> >
>> >Joe
>> >
>> >
>> >
>> >**********************************************
>> >Joe Sommer
>> >2378 Nantucket Circle, State College, PA 16803
>> >814.234.4773     anvilus9-at-adelphia.net
>> >http://www.anvilus.com
>> >
>>
>