oh no, I'm still confused! You write that it should be 150 ohms in normal unpressed condition, and 480 ohms with the button pressed. So far so good, that's how the handle I bought is behaving. But you say the switch should be in the N.O. state when unpressed. Wouldn't this mean the current is going through both resistors and is therefore 480 ohms? Then 150 when pressed (closed, bypassing the 330 ohm resistor)? It's highly possible that I don't understand exactly what 'Normally Open' means.
Here is what the Open EVSE Wiki says http://code.google.com/p/open-evse/wiki/J1772Basics : "The proximity circuit should read about 450-500 ohms when measured from proximity to ground. When the button is pressed the reading should drop to about 150 ohms. The change in resistance signals the EV to stop pulling current. The relay in the EVSE will stay closed until the pilot is dropped however J1772 compliant EVs will stop pulling significant current." This is counter to the readings you listed, but consistent with the microswitch being N.O. I think. I think I may drive downtown and ohm out a Chargepoint connector today at lunch :-) david. ----- Original Message ----- > From: Rush Dougherty <[email protected]> > To: 'David Ladd' <[email protected]>; 'Electric Vehicle Discussion List' > <[email protected]> > Cc: > Sent: Wednesday, May 1, 2013 9:56 AM > Subject: RE: [EVDL] J1772 proximity stuff > > I'm not sure I'm an expert on the circuit, but I do sell the J1772 Plugs > and > Inlets and actually helped the factory I buy mine from to implement the > Proximity circuit in the Plugs that they manufacture and I sell. > > With the switch, in its' normal position, unpressed, you should read > 150ohms. When it is pressed, to release the catch and also send a signal to > the onboard charger to stop charging, it should read 480 ohms. > > Some of the confusion arises from the switch itself, it can be configured to > be either NO or NC in its' unpressed state. For this application it should > be NO in its' unpressed state. > > Rush > www.TucsonEV.com > > > > >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On >> Behalf Of David Ladd >> Sent: Wednesday, May 01, 2013 8:03 AM >> To: Electric Vehicle Discussion List >> Subject: [EVDL] J1772 proximity stuff >> >> I'm working on assembling a home EVSE out of old parts (EVI DS-50 and >> J1772 plug from ebay). I got the cord/plug yesterday, and I'm just not > clear >> on what I should be seeing when putting a meter on the connector. >> >> Measuring proximity to ground I get 150ohm. When I press the switch, I > get >> 480ohm. According to http://code.google.com/p/open- >> evse/wiki/J1772Basics it should be the other way around, 480ohm, then >> 150ohm when the switch is depressed. >> >> Is my connector wired wrong? I'm finding all kinds of conflicting > advice > on >> this when I google it. I don't think it matters either way for me > since > I'm just >> charging a conversion with a dumb charger, but I'd like to have it set > up > in >> accordance to the spec. Before trying to open up the connector I'd > like > to >> verify with the experts what I should be 'seeing' at the plug. >> >> david. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
