Hi Dwayne, As far as I know, truly achieving such accuracy will require periodic re-calibration to transfer standards which are themselves kept calibrated to primary standards. I don't think there is any way (short of replicating a primary standard) to make an instrument which will simply measure true 6.5 or more digits of accuracy for years on end with no re-calibration. This means that whoever developed this instrument for this customer would have to also provide a means of re-calibration, such as instructions for cal labs. I don't even know if a typical cal lab would be willing to perform calibration on a custom instrument. All of this is doable but I don't think it will be less expensive, when you consider all the difficulties, than an off-the-shelf bench multimeter. Note that the Agilent 34401A is a classic 6.5 digit multimeter of high quality and can be purchased new in the $1100 USD range. Price climbs very quickly above 6.5 digits, of course ($9300 for the 8.5 digit Agilent 3458A). The majority of the cost comes from the "infrastructure" within the meter for achieving the basic voltage accuracy. Most of the measurements besides voltage simply "piggy-back" on this basic capability, so I do not think that deleting the additional functions would save very much money. Sean On Fri, Nov 15, 2013 at 3:14 PM, Dwayne Reid wrote= : > Good day to all. > > We had an enquiry come in several months ago from a client wanting an > accurate DC voltmeter with specs similar to the Keithley 2000 (6.5 > digit), 2001 (7.5 digit) or 2002 (8.5 digit) Digital > Multimeters. Although they are currently using the Keithley units > for prototyping, they want something less expensive for > production. As far as I know, they need to monitor only a single > range of DC voltage. > > We originally turned down the work - they are asking for precision > far greater than anything that I've ever done in the past. Quite > frankly, I thought that was the end of it. > > However, they got back to us this week and are still wanting someone > to develop this for them. We are not interested - we already have > more work than is comfortable and this project would take far too > long a development period for it to be profitable for us. > > But - perhaps someone on the PIClist would be interested in taking > this project on. If so, please send a *private* message to me at > dwayner@planet.eon.net and I'd be happy to pass on the contact info. > > You would deal with the customer directly - we would not be involved > in any way. > > I hope that someone might like to take this project on! > > dwayne > > -- > Dwayne Reid > Trinity Electronics Systems Ltd Edmonton, AB, CANADA > (780) 489-3199 voice (780) 487-6397 fax > www.trinity-electronics.com > Custom Electronics Design and Manufacturing > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .