Just be careful and ask the supplier what type of encoder is mounted on the servo. There are encoders and there are encoders. My http://en.bergerda.com/ servos use a Japanese brand which they claim are better than some of the Chinese ones out there but are also considerably more expensive. Differential output from the encoder is a must have to reduce the effects of electrical noise.
John > -----Original Message----- > From: andrew beck [mailto:andrewbeck0...@gmail.com] > Sent: January-28-21 1:14 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Fanuc Servos? > > You can buy Chinese yaskawa copy ac servo drives 2.4kw for like 260usd. So > it's just not worth it now. I just sold my fanic drives in the end. Its > so nice to just bolt on some matched servo drives that just work out of the > box. > > On Thu, 28 Jan 2021, 14:20 Jon Elson, <el...@pico-systems.com> wrote: > > > On 01/27/2021 11:35 AM, Todd Zuercher wrote: > > > How useable are Fanuc's servos and amps with Linuxcnc? My understanding > > is that it is very involved to try to force them to work with anything > > other than a Fanuc control > > I make converters for the two most common types of Fanuc > > encoders used on brushless motors. > > I also make a digital servo amp for them that can be used > > with my PWM controller. > > The older "red cap" motors had encoders with standard > > quadrature plus index output, but the commutation signal was > > proprietary. I have a board that converts the commutation > > to industry-compatible "Hall" signals. > > > > The newer type is serial, but my converter produces > > industry-compatible quadrature plus index, plus the "Hall" > > signals. Note there are absolute and incremental versions of > > these encoders. > > The problem with the incremental versions, like (alpha)I64, > > is that they are lost when power is applied, so they need > > you to crank the motor past the index location by hand after > > every power on, before commutation is available. So, these > > encoders need power-off brakes and battery backup if the > > control is ever turned off. > > The absolute version have additional low-res data tracks > > that allow the encoder to know the angle immediately at > > power-on, so no battery is needed to have commutation > > immediately on power on. > > > > Now, the Fanuc servo amps are more difficult, as about 1984 > > they stopped releasing any documentation on their > > electronics. So, it is essentially impossible to find any > > schematics or connection info for their amps. Most of the > > brushless amps take SIX PWM signals per axis, so > > the controller sends separate PWM to EACH transistor. This > > moves all the smarts to the controller, but it complicates > > things a bit. > > > > Jon > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
