They go bang because of excessive current not voltage...usually if upper and lower devices in the bridge are 'on' simultaneously... 40v across .5 ohms = 80A peak, 3200W instantaneously.... your PSU will do that for a few 100uS no problem!
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Cheers, I did check the outputs when the onboard processor was controlling the motors and could see the logic highs and lows on the step and dir. pins, but when I tryed to inject a signal in to it my self nothing happened. I was just wondering if anyone knew if the enable pin can completely switch off the chip? as the board is double sided and very crowded it is difficult to see what is going on. (and after the last one went bang , I'm not keen to randomly test points) I was hoping that the enable switch is also controlled by the processor, which would explain why the motors wont work when I try to control them.Quote:
Opto's if none is found when you fire the circuit up it maybe because they require some voltage
Looks like I must have shorted something whist I was trying to get it to work. Is this driver set up usually Ok?Quote:
They go bang because of excessive current not voltage...usually if upper and lower devices in the bridge are 'on' simultaneously... 40v across .5 ohms = 80A peak, 3200W instantaneously.... your PSU will do that for a few 100uS no problem!
P.S if you are throwing them away KIP, my bin has plenty of space:beer:
Fair play, It was worth a try tho eh :naughty: Damm you yorkshiremen....Quote:
I have a good arm...although the bin in Devon is a throw too far for me :D
Im not one to be beaten so had another crack at the control board. Rewired the inputs to the L297, bypassed the output relays and it worked.............:dance:
......Until I turned the Vref pot the wrong way and fryed the output chips AGAIN. So at least I've found something i'm good at. :rofl:
Question time. If all 3 motors are 2 phase, 8 wire and configured in parallel, then why is one of the motors wired differently at the board plug? surley the phases cant change as the motor wouldnt turn...
Hope to make some real progress this weekend. so post some more pics soon
Forgot to ask if anyone knows of a good cuircuit to test stepper drives? I'm looking for an MPG type thingy that dosnt require a pc or mach, but will generate the correct pulse voltages, timings etc for step and direction
Maybe i should post In the drivers section?
Cheers
For a really simple 'get you up & running testing a stepper nice & quick', it's really handy to have one of these in your component tray...
http://www.datasheetcatalog.org/data...stems/5804.pdf
They don't make 'em anymore so they're getting a little scarce, but still available here...
http://www.cricklewoodelectronics.co...0&cat=0&page=1
Pin 11 is the step input - switch that pin low/high - your steppers move. Job done.
Cheers guys.
That sounds perfect for testing the motors, I was also after something to control the whole driver/ motor setup without a pc.Quote:
For a really simple 'get you up & running testing a stepper nice & quick', it's really handy to have one of these in your component tray...
http://www.datasheetcatalog.org/data...stems/5804.pdf
Good idea, he's not biting yet tho..... maybe have to offer some cash:heehee:Quote:
Tell you what, Nottingham is nearer and I can take them down to Bristol on the 22nd when I go to the show.
Let's shame the bastard
Is that a CNC/ machinery show?
Yes I would like to be able to control the whole driver and motor system without a pc. I was thinking along the lines of a varible pulse generator that could feed each axis as required by using a joystick, (like on a Playstation controller) That way i could control direction with the pad and the speed with a trim pot, If it works i might look at using a ps3 analouge type joystick so the speed it proportional to the stick movement.Quote:
Ross, are you saying to exercise the stepper drivers directly without a PC, or to drive the motors without a stepper driver?
Ive been looking on the the net at 555 timer circuits feeding a schitt trigger, but I'm not skilled enought to design it for the correct voltages and pulse timings:sad: