In case it might be of interest, I posted some pictures of a Fanuc MPG I got from eBay: http://www.wallacecompany.com/machine_shop/fanuc_mpg/
I thought the detent mechanism would be some fancy magnetic system, but is a simple gear running against a roller and spring. I thought this would wear quickly, but the MPG is over thirty years old and still looks like new inside. There is a spring wrapped on the encoder input shaft which is driven by a pin on the detent disk. This allows for misalignment between the the two rotating bits. Each mark on the knob is a complete quadrature cycle. The cycle also has a dead zone such that the transitions take place at the middle, between the marks, and are well settled when getting close to resting at a mark/detent. The encoder has a slotted mounting flange so that it may be rotated to adjust to the knob markings. This also makes the phase changes close together, so a slower LinuxCNC software encoder may not be fast enough for reliable function. Before adjusting the encoder alignment, the knob needs to be adjusted so that the knob marks align with the detents and face plate pointer. There are two Allen screws that set the knob to the input shaft. All screws are metric. The A and B channels seem to have push-pull drivers and give clean and sharp signals when hooked directly to inputs without pull-ups or external drivers. The signals are single-ended (0 and 5 Volts). There is no index channel. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ Don't Limit Your Business. Reach for the Cloud. GigeNET's Cloud Solutions provide you with the tools and support that you need to offload your IT needs and focus on growing your business. Configured For All Businesses. Start Your Cloud Today. https://www.gigenetcloud.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
