Hi Rich, Thanks for your reply. I think that I'll opto-isolate the PWM signal into the live controller. Then use a low pass RC filter, then feed it through a voltage following op-amp. For the low voltage supply on the live side, I'm thinking of just using a 10V Zener in series with a power resistor, with the usual decoupling capacitors. Thanks again. Peter Homann mailto:Peter.Homann@adacel.com Adacel Technologies Limited, 250 Bay St, BRIGHTON, 3186, AUSTRALIA http://www.adacel.com Telephone +61 (3) 8530 7777, Facsimile +61 (3) 9596 2960 Mobile 0421-601 665 -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Rich Sent: Friday, 29 November 2002 2:42 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: Generating an isolated 0-10Vdc voltage Isolating an analog signal is more challenging because opto-isolators are not linear. Motorola used to have a linear opto coupler, HP has some circuitry for making a linear opto. A V/F converter with and opto isolator to a F/V converter will do just fine. Buffer the output with an op amp, i.e., 0p07, 0p37, and so on. Pretty simple to implement. Another way is a simple charge pump with a 555 buffered output with LM324. I do not know what design constraints you have. That will be your starting point. Good luck, Rich ----- Original Message ----- From: "Peter Homann" To: Sent: Thursday, November 28, 2002 8:00 PM Subject: Re: Generating an isolated 0-10Vdc voltage > The 0-10Vdvc is only a control voltage. 2-3mA would be sufficient. > Regulation, I'm not sure, probably 10 - 50mV would be OK. > > > Peter Homann > mailto:Peter.Homann@adacel.com > Adacel Technologies Limited, > 250 Bay St, BRIGHTON, 3186, AUSTRALIA > http://www.adacel.com > Telephone +61 (3) 8530 7777, Facsimile +61 (3) 9596 2960 > Mobile 0421-601 665 > > > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Rich > Sent: Friday, 29 November 2002 11:54 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: Generating an isolated 0-10Vdc voltage > > > What is the power delivered to the load, what is the regulation and > accuracy? > > ----- Original Message ----- > From: "Peter Homann" > To: > Sent: Thursday, November 28, 2002 7:41 PM > Subject: [EE]: Generating an isolated 0-10Vdc voltage > > > > Hi, > > > > I'm planning to generate a 0-10V analog voltage using the PIC PWM, RC > > filter, and op-amp. > > > > The question is how do I isolate the output voltage. The voltage is to > drive > > a 90V DC motor controller where the controller ground is live. > > > > One solution is to opto-isolate the inputs to the PIC and have the whole > > circuit live. I would have to power the PIC circuit via a 12V zener and > > resistor. > > > > The other option is to isolate the 10V signal via a transformer. Does > anyone > > have experience with this or other alternatives? > > > > Thanks, > > > > > > Peter Homann > > mailto:Peter.Homann@adacel.com > > Adacel Technologies Limited, > > 250 Bay St, BRIGHTON, 3186, AUSTRALIA > > http://www.adacel.com > > Telephone +61 (3) 8530 7777, Facsimile +61 (3) 9596 2960 > > Mobile 0421-601 665 > > > > -- > > http://www.piclist.com hint: PICList Posts must start with ONE topic: > > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > > > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads