Eric, Here is my $.02 input.
For voltage, I typically need 10mV to 200VDC and 50mv to 500VAC, true RMS is a good thing. For current, I typically need need 1mA - 10ADC inline, 20mA-10AAC inline and 20mA to 75A with an inductance coil. As for channels, it depends on the use. If I am going to put this to work measuring current in a wiring panel, then I would need 10-20 channels of inductance coils. If I am doing A-D voltage I would think that blocks of 4-8 channels would be very useful. Most good meter systems have a variable gain instrumentation amplifier in front of the sensor to increase the dynamic range and reduce low end circuit noise. Not much you can do about the mux loss of precision in things at this level. I know it may not be what you were looking at, but what I would love is a small power meter that measures 2-4 voltage inputs (three legs and neutral to ground,) N current channels from inductance coils, frequency, load reactivity (AKA power factor or phase distortion.) I think it is too much to ask, but noise on neutral would also be nice. With today's microcontrollers, I would put in readings for instantaneous, min and max in last hour, 5 minute average and totalizer as appropriate. You would want to be able to program the chip with the coil on each channel to convert measured current to line current. To give you an idea, this would cost thousands of dollars as a dedicated box, so there is definitely room for something cheaper. The issue is for this kind of app, you are dealing with AC mains and electrical compliance is a serious issue. For me, 4-20mA is just a precision resistor away from voltage, so I rarely ask for it as a feature. Being able to pair two inputs and use them in differential mode is more interesting to me. jerry On 09/12/2013 03:09 PM, Eric Vickery wrote: > I am looking at developing a multi-meter of sorts I want to get some input > from the group. > What voltage ranges would be most useful to you? > What current ranges would be most useful to you? > Do you have a need for a 4-20ma reader? > How many channels would you like to see? > Any other ideas you might have would be appreciated. > > Thanks, > Eric > www.hobby-boards.com ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. Consolidate legacy IT systems to a single system of record for IT 2. Standardize and globalize service processes across IT 3. Implement zero-touch automation to replace manual, redundant tasks http://pubads.g.doubleclick.net/gampad/clk?id=51271111&iu=/4140/ostg.clktrk _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
