> 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.
My VFD is an Omron Varispeed V7. The analog output can be configured as a pulse-train with 1440 Hz max frequency, but then you can only monitor either commanded frequency(rpm) or actual frequency. When set to analog 0-10 V mode you can program it to show a lot of other parameters like output current, power, PID error etc. I will be using a NC relay on the VFD in the e-stop loop, so this current monitoring would be more 'for fun' and with the ability to log the spindle current to disk for later analysis. This is how a lot of academic papers 'prove' that their super-duper toolpath generator is better or worse than some other toolpath: smoother and gentler variations in spindle load. Zig-zag paths for example generate huge current spikes whenever the tool is driven into the material at full width. AW ------------------------------------------------------------------------- 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
