matrixtest
I'm doing a presentation about NI PXI and such test equipment for school.
And I am explaining what the multiplexer and matrix modules can be used for.
The multiplexer is simple: Connect, for example, all voltage measurement points to the multiplexer inputs, and a DMM to the output, and cycle through them in order and acquire measurements.
But what exactly is the matrix used for? I can't figure out what the advantage of this one is.
Page 13 here shows a diagram etc: enter link description here
If you remove the cap you'll have a metal dingus where you can solder a wire to. You then have a test lead which can hook onto wires, IC pins, resistor leads, you name it. Use it to make signal or power connections or as measuring leads to a DMM.
They allow for finer work than alligator clips, which serve the same function:
It's a good idea to have some test leads within reach, and to have them in different colors, so that you can tell the signals apart easily when the wiring becomes spaghetti-like; for instance use black for ground and red for your positive power supply.
INSRIS will be insulation resistance. Approximately 500VDS is applied between L/N and E and the current measured. For Class I (earthed) appliances, this should be greater than 1MOhm, though anything below about 5MOhm should be looked into. A lot of appliances will get values in the range of hundreds of MOhm, and I think the tester used in your printout must not read higher than 299MOhm.
VIS is visual inspection.
DI is double insulated, i.e. class II - no earth bond or insulation resistance test to carry out.
L VOLTAGE is low voltage i.e. class III - no earth bond or insulation resistance test to carry out.
I'm not familiar with the specific software or tester used for this printout, but most of the testers will log data and this can be then put into a report.
As stated in another answer, a lot of PAT testing companies just say 12 months between combined inspection and testing. In an office environment (warning PDF), stationary equipment can go 4 years without testing, but hand-held equipment needs testing every year. Visual inspections need to be carried out more frequently. It gets complex when you have a lot of things that need testing and bring new devices onsite.
It is really important to note that these are only guidelines though. As far as I know, there is no law requiring PAT testing, just that you maintain safe electrical equipment.
In a small company I used to work fosense sent two people on a 1 day training course at about £120 each. This paid for itself in a year.
Best Answer
The multiplexer isn't enough if, for example, you would like to measure the voltage with one and the frequency with another instrument at several points. Another example would be to measure the voltage at different points under various loads. Then you have to connect the DMM AND one of several loads to various points.
Generally speaking you can run more complex mesurement tasks unattended over a long time.