Author Topic: Changing voltage polarisation  (Read 5997 times)

Offline Rafal_Typiak

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Changing voltage polarisation
« on: March 22, 2011, 12:56:26 PM »
Hi.
I was wondering if there was a way to change a standard "0 -> +supply voltage" polarisation to a "-supply -> + supply" ?
I was thinking of doing it on a 050 or 088.
If it's possible, than what do I need to do to achieve it?

Thanks,
Rafal Typiak

Offline Stefan

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Re: Changing voltage polarisation
« Reply #1 on: March 23, 2011, 04:37:44 PM »
Hello Rafal,

I'm really sure what you mean but we can't use negative voltage.

Best regards
Stefan

Offline Rafal_Typiak

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Re: Changing voltage polarisation
« Reply #2 on: March 24, 2011, 07:24:12 AM »
Heh,
I've just read my first post again and saw that you might have actually misunderstood me. My fault  :D. I wasn't asking if I can power the controllers from '-supply +supply' but if I could generate such voltage on the outputs of the controllers. I wanted to power a sensor which needs a '-12 +12' power supply.

Offline Stefan

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Re: Changing voltage polarisation
« Reply #3 on: March 24, 2011, 11:44:40 AM »
Hello,

I'm sorry, it's not possible.

Best regards
Stefan

Offline Rafal_Typiak

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Re: Changing voltage polarisation
« Reply #4 on: March 24, 2011, 01:26:24 PM »
Oh well,
thanks anyway.

Rafa?

bgtwuk

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Re: Changing voltage polarisation
« Reply #5 on: March 29, 2011, 01:21:11 AM »
I thought that you can use the pin 40 and pin 50 to form an H bridge.

Or am I on a different angle?

Offline Stefan

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Re: Changing voltage polarisation
« Reply #6 on: March 29, 2011, 08:11:04 AM »
Hello,

Yes, that's correct. But the H-bridge just change supply and ground between 2 pins.

You don't get a negative voltage related to ground.

Best regards
Stefan

scott.jones

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Re: Changing voltage polarisation
« Reply #7 on: May 13, 2011, 05:08:01 AM »
I have sucessfully controlled a Rexroth PID controller that require -10 to +10 VDC signal using a H-Bridge output.  It is my understanding that with most devices simply reversing the polarity will work.   I set the PWM freqeuncy to 4000 Hz but I still had to use a RC filter to smooth out the signal.