Tuesday, June 28, 2011

PXI DMM Speed Showdown: Agilent vs Brand X

Below is a video demonstrating how Agilent's M9183A PXI DMM is over 10 times faster in a transactional test setup compared to Brand X's PXI DMM (you can probably guess who Brand X is). Transactional testing refers to automated test setups where the DMM and switching has to be reconfigured for each measurement or test point on the DUT. That means at each test point the DMM is configured, armed (*INIT command), and the measurement is fetched from memory into the test software.Everything in the test is the same except the DMMs so each test setup has the same switching, same PXI chassis, same code, and the DMM measurement aperture time is the same. Check out the video below.

The reason that Brand X's DMM is so much slower is because its measurement arming time is ~ 6 ms! Agilent's M9183A measurement arming time is < 100 us. With an arm time of 6 ms Brand X is wasting the benefit gained by the high speed PXI bus. In fact, with such a large arm time a 'box' DMM using USB, LAN, or GPIB is faster. For instance Agilent's 34410A DMM takes only ~ 2 ms to make a measurement (that is including IO latency). 

For more info on Agilent's PXI DMM click here