On Fri, 5 Dec 2014, Mark Johnsen wrote: > Date: Fri, 5 Dec 2014 10:34:17 -0800 > From: Mark Johnsen <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: [Emc-users] Gear Tooth Sensor wired as encoder to 7I77 > > I am in the process of working through my Supermax Aniliam Crusader M > conversion to Mesa 5i25/7i77. > > At this point, I'm bench testing everything on a table in the kitchen (why > anywhere else?). I hadn't really thought everything through and thought > I'd just pop an encoder on the spindle somewhere to work w/ the Automation > Direct GS2 VFD, until I ran across John Thornton's Forum post referring to > Jon Elson's webpage about not being able to find a good place to locate the > spindle encoder. https://pico-systems.com/bridge_spindle.html > > How do I wire the Allegro sensor to the 7i77 board? I'm confounded on the > pull-up resistor part of it... And, the values for the capacitor CL & > Rpullup resistor at 5v vs 12v used in the data sheet. > > Allegro DATASHEET: > http://www.allegromicro.com/en/Products/Part_Numbers/0667/0667.pdf > Refer to Page 11, Figure 6, Typical circuit for proper device operation. > Page 3, Output Rise time is based on resistor Rpullup 1K ohm and capacitor > 4.7nF, Vpullup 12Vdc (of course 12vdc...). > Digikey link: > http://www.digikey.com/product-detail/en/ATS667LSGTN-T/620-1328-1-ND/2042758 > > FROM THE 7i77 Manual, p54: http://www.mesanet.com/pdf/parallel/7i77man.pdf > > ENCODER INPUTS > INPUT COMMON MODE RANGE -7 +12 Volts > INPUT TTL MODE THRESHOLD 1.4 1.8 Volts > DIFFERENTIAL MODE IMPEDANCE 131 135 Ohms > COUNT RATE ---- 2 MHz > (With standard firmware/setup) > > WIRING? > First off, this looks like a single-ended encoder setup, so I would move > the jumpers on the 7i77 to the left-hand position for single ended > operation. > I would connect 5v of the encoder output to the Vcc for the sensor. (It > does look like 12V would work for the sensor and the 7i77, giving better > noise immunity, but getting 12vdc is funky and let's not go there unless > needed). I am powering the 7i77 w/ external 5vdc, not from the 5i25.
The 7I77 encoder inputs have 2K pullups (to 5V) already so a direct connection as Andy suggested should just work. I would not drive the inputs with 12V, this is at the limits of the input range and will not improve noise rejection much (the single ended input threshhold (1.65V) will not change so you will gain noise immunity on the high state but not in the low state) > > It doesn't seem right to connect Vpullup to the A+ input on the encoder > inputs? What do I connect to the A+? Do I connect both Vcc and Vpullup to > 5vdc? > Also, how would Rpullup and CL change for 5vdc vs. 12Vdc? > > Lastly, might there be any suggestions on where to put the encoder on the > spindle, like the back/top of the AC motor? I haven't really looked, but > thought I'd ask. Maybe there's another location for it, but certainly not > in the case like Jon Elson's sensors... > > Thanks, > Mark > ------------------------------------------------------------------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & more > Get technology previously reserved for billion-dollar corporations, FREE > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
