On Sat, 2008-01-19 at 11:54 -0800, Peter C. Wallace wrote: ... snip > A simple Voltage to frequency converter would probably do, for example the > AD654 in 8 pin DIP is probably quite a better than required. (500KHz max > frequency, .03% linearity) > > I would count the frequency with one of the spare encoder counters (set up > for > up/down mode) and use count difference accumulated over some number of sample > periods (to average out the sample period jitter) ... snip
On my Mitsubishi Freqrol U100 and Z200 VFD's there is a monitor output called FM, which is an 8 Volt pulsed signal with a frequency of 1440Hz at full scale. Both VFD's monitor output frequency (motor speed), or the U100 can be programed to monitor output current. I suppose a opto-coupler could be used to (almost) directly connect this signal to an encoder input. I'm not sure how handy motor speed would be. The motor current would be nice to have though. All my VFD's have a number or alarm outputs, which should probably be incorporated into my configuration, but most likely I won't get to it until something bad happens. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
