<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">In all the cars I’ve looked at, signal and chassis ground are connected (and at multiple points in the car).<div class=""><br class=""></div><div class="">As we don’t have chassis ground to the OVMS module, it is not possible to pass it on to the HUD/dongle. Best we can do is signal ground (which should be connected to chassis ground upstream).</div><div class=""><br class=""></div><div class="">That’s my thinking, anyway.</div><div class=""><br class=""></div><div class="">Regards, Mark.<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 4 Apr 2018, at 2:07 AM, Greg D. <<a href="mailto:gregd2350@gmail.com" class="">gregd2350@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
  
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" class="">
  
  <div text="#000000" bgcolor="#FFFFFF" class="">
    Hi Mark,<br class="">
    <br class="">
    That's the spec I am currently using.  But, I had one question that
    I have not heard back on yet, that of signal ground vs chassis
    ground.  I have them tied together on the OBDII connector end, but
    wonder if we should only connect signal ground, or if they should be
    separate wires between both ends, or just leave the chassis ground
    unconnected.  I've seen it done various ways in various OBDII
    hacking diagrams.  Is there even a chassis ground pin on the DA26
    connector?<br class="">
    <br class="">
    Functionally it probably doesn't make a lot of difference, but for
    RFI/EMC purposes, it may be important.  I always assigned that task
    to someone who knew what they were doing :); I just knew it was
    something to be attended to.  Without over-engineering this, what is
    the right treatment for chassis ground?<br class="">
    <br class="">
    15cm cable length should be ok, as HUDs should have long enough
    cables to reach under the dash, but my first reaction was that it
    seemed a bit short.  I guess it depends on where and how the OVMSv3
    module gets mounted.  The cable should be long enough to be able to
    to be tied back to the unit and/or its mounting situation. 
    Otherwise, an OBDII dongle would be forced to just hang there,
    potentially over or under one's feet.  Maybe 25cm would be better?<br class="">
    <br class="">
    Greg<br class="">
    <br class="">
    <br class="">
    <div class="moz-cite-prefix">Mark Webb-Johnson wrote:<br class="">
    </div>
    <blockquote type="cite" cite="mid:47693EB3-86DE-487B-AA58-A430A4FF67CA@webb-johnson.net" class="">
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" class="">
      <div class=""><br class="">
      </div>
      Regarding the HUD cable, I have asked the suppliers for this,
      according to the following specification:
      <div class=""><br class="">
      </div>
      <blockquote style="margin: 0 0 0 40px; border: none; padding:
        0px;" class="">
        <div class="">
          <div class="">OVMS 3 HUD expansion cable:</div>
          <div class=""><br class="">
          </div>
          <blockquote class="" style="margin: 0px 0px 0px 40px; border:
            none; padding: 0px;">
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">Pinout: “HUD"</span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;"><br class="">
                </span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">J1962-F   DA26-M
                   Signal</span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">4         8      
                  Chassis/Power GND</span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">5         8      
                  Chassis/Power GND</span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">6         16    
                   CAN-H (primary CAN)</span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">14        6      
                  CAN-L (primary CAN)</span></font></div>
            <div class=""><span class="" style="font-size: 14px;
                font-family: "Andale Mono";">16        18    
                 +12V Vehicle Power</span></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;"><br class="">
                </span></font></div>
            <div class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">Notes:</span></font></div>
            <div class="">
              <ul class="MailOutline">
                <li class=""><span class="" style="font-size: 14px;
                    font-family: "Andale Mono";">Require
                    120ohm resistor between DA26 pins 16 and 6 (this can
                    be either at J1962 or DA26 ends).</span></li>
                <li class=""><font class="" face="Andale Mono"><span class="" style="font-size: 14px;">J1962 pins 4 and
                      5 are both connected to single DA26 pin 8.</span></font></li>
                <li class=""><span class="" style="font-family:
                    "Andale Mono"; font-size: 14px;">J1962 end
                    should be FEMALE plug with straight cable. DA26 end
                    should be MALE.</span></li>
                <li class=""><span class="" style="font-size: 14px;
                    font-family: "Andale Mono";">Both ends
                    should be enclosed in shells, and cable should be
                    15cm in length.</span></li>
              </ul>
            </div>
          </blockquote>
          <div class=""><br class="">
          </div>
          <blockquote class="" style="margin: 0px 0px 0px 40px; border:
            none; padding: 0px;">
            <div class=""><img apple-inline="no" id="E2865559-D78E-4F6A-878A-E54A6ABB0C12" class="" src="cid:8C66E0BD-5817-4751-A7A3-2830F75788F3" moz-do-not-send="true"></div>
          </blockquote>
        </div>
      </blockquote>
      <div class="">
        <div class=""><br class="">
        </div>
        <div class="">I think that is correct. If there are any changes, please
          let me know.</div>
        <div class=""><br class="">
        </div>
        <div class="">Regards, Mark.</div>
        <div class=""><br class="">
          <blockquote type="cite" class="">
            <div class="">On 28 Mar 2018, at 7:45 AM, Greg D. <<a href="mailto:gregd2350@gmail.com" class="" moz-do-not-send="true">gregd2350@gmail.com</a>>
              wrote:</div>
            <br class="Apple-interchange-newline">
            <div class="">
              <div class="">Hi Steve,<br class="">
                <br class="">
                Ha, didn't know that.  Thought they were all DB's...
                 Thanks, corrected.<br class="">
                <br class="">
                Greg<br class="">
                <br class="">
                <br class="">
                Stephen Casner wrote:<br class="">
                <blockquote type="cite" class="">Greg,<br class="">
                  <br class="">
                  A nit: The connector is more correctly identified as
                  DA-26, see<br class="">
                  <a href="https://en.wikipedia.org/wiki/D-subminiature" class="" moz-do-not-send="true">https://en.wikipedia.org/wiki/D-subminiature</a><br class="">
                  <br class="">
                                                       -- Steve<br class="">
                  <br class="">
                  On Tue, 27 Mar 2018, Greg D. wrote:<br class="">
                  <br class="">
                  <blockquote type="cite" class="">Hi folks<br class="">
                    <br class="">
                    In a fit of prose, if not Shakespeare, I took a pass
                    at creating the<br class="">
                    documentation chapter for the OBD2ECU task.
                     Comments, corrections, and<br class="">
                    general feedback is requested.  Is there anything
                    significant missing?<br class="">
                    Mark, if this looks acceptable, can it be posted to
                    the Google Doc, or<br class="">
                    send me an invite such that I can do so?<br class="">
                    <br class="">
                    Note that I don't have any reference material on the
                    OBDII-to-DB26<br class="">
                    cable, other than the wiring.  If we eventually have
                    a purchase source,<br class="">
                    that should get referenced, or lacking that, perhaps
                    pointers to where<br class="">
                    the connectors can be purchased?  Placeholders are
                    noted, but only<br class="">
                    that.  For the EEs in the group, a question:  I have
                    both signal and<br class="">
                    chassis grounds connected together on the OBDII
                    connector; should they<br class="">
                    be, or just signal ground?<br class="">
                    <br class="">
                    I think it would also be helpful to include a table
                    of what metrics are<br class="">
                    available (supported) on what vehicles, as an aid to
                    those who want to<br class="">
                    remap things for monitoring on an OBDII HUD or
                    Dongle.  A glance at the<br class="">
                    available documentation didn't turn up anything, so
                    I took a first pass<br class="">
                    at the table.  See the attached, which includes what
                    I know of the<br class="">
                    Roadster's implementation (since I have one and have
                    studied the code a<br class="">
                    bit).  I would rather not try to guess at the other
                    cars.  Could the<br class="">
                    various vehicle authors contribute their columns to
                    the table?  Send me<br class="">
                    an updated spreadsheet, and I will do the merge.<br class="">
                    <br class="">
                    Thanks!<br class="">
                    <br class="">
                    Greg<br class="">
                  </blockquote>
                  _______________________________________________<br class="">
                  OvmsDev mailing list<br class="">
                  <a class="moz-txt-link-abbreviated" href="mailto:OvmsDev@lists.teslaclub.hk">OvmsDev@lists.teslaclub.hk</a><br class="">
                  <a class="moz-txt-link-freetext" href="http://lists.teslaclub.hk/mailman/listinfo/ovmsdev">http://lists.teslaclub.hk/mailman/listinfo/ovmsdev</a><br class="">
                </blockquote>
                <br class="">
                _______________________________________________<br class="">
                OvmsDev mailing list<br class="">
                <a href="mailto:OvmsDev@lists.teslaclub.hk" class="" moz-do-not-send="true">OvmsDev@lists.teslaclub.hk</a><br class="">
                <a class="moz-txt-link-freetext" href="http://lists.teslaclub.hk/mailman/listinfo/ovmsdev">http://lists.teslaclub.hk/mailman/listinfo/ovmsdev</a><br class="">
              </div>
            </div>
          </blockquote>
        </div>
        <br class="">
      </div>
      <br class="">
      <fieldset class="mimeAttachmentHeader"></fieldset>
      <br class="">
      <pre wrap="" class="">_______________________________________________
OvmsDev mailing list
<a class="moz-txt-link-abbreviated" href="mailto:OvmsDev@lists.openvehicles.com">OvmsDev@lists.openvehicles.com</a>
<a class="moz-txt-link-freetext" href="http://lists.openvehicles.com/mailman/listinfo/ovmsdev">http://lists.openvehicles.com/mailman/listinfo/ovmsdev</a>
</pre>
    </blockquote>
    <br class="">
  </div>

_______________________________________________<br class="">OvmsDev mailing list<br class=""><a href="mailto:OvmsDev@lists.openvehicles.com" class="">OvmsDev@lists.openvehicles.com</a><br class="">http://lists.openvehicles.com/mailman/listinfo/ovmsdev<br class=""></div></blockquote></div><br class=""></div></body></html>