Thanks for the info. It's not quite what I'm looking for though.
I like the yocto-volt, but the issues that concerns me are the relatively small input resistance and the availability of the product (is it on the market for sale in 10 years from now).
I'm building a professional test system for use in a LEAN production environment. It means that every product or product series shall have its own test equipment, hence it must be relatively cheap (~2000$) and in a small box with a laptop mounted on top of it.
The test system I'm building consists of a few power supplies, relays, PLC/Logic board, communication interfaces, linear actuator controller, in-circuit production programmer and some other equipment.
It's much to compact into a small box where most the equipment should preferably be mounted on DIN rails.
The DMM I wish for is the U2741A by Keysight/Agilent:
http://www.keysight.com/en/pd-1420686-pn-U2741A/usb-modular-digital-multimeter-5-digit?cc=US&lc=engBut it's a little overspect., large, quiet expensive and it's not DIN mountable (but can live with that it isn't).
This is actually something like I'm searching for (but it's a bit slow): Carlo Gavazzi - Digital Panel Meters Modular signal conditioner Type USC-DIN
http://www.carlogavazzisales.com/pdfs/controlprod/USC%20DS%20ENG%200804.pdfDMM spec (all of this should apply in the full industrial temperature range):
I need to measure a small current ~10µA. But in the system I'm building it can be done by measuring 0,01V over 1kOhm when 10µA is flowing through it.
In another situation I need to measure a voltage of around 40 volts but only with 100mV to 200mV precision.
I also need to measure a current of about 1mA to 300mA with an accuracy of about +/-1mA. And also 100mA to 1A with an accuracy of 50mA.
The measurements shall be read by a computer or PLC.
The measurement ranges could simply be some relays and resistor added to the equipment that I control with the PLC/computer.
Hope someone knows of a reliable/stable company who make a product like this.