Low sample rate when measuring 2 channels simultaneously on AMREL PD5-40

[Donnielas]

I am measuring voltage and current on a AMREL PD5-40A Power Supply. I use drivers downloaded at NI.com

I've simply put the "read VI" and "save to measurement file VI" in a while loop.

The sample rate of the data is lowered by half when I measure both voltage and current compared to when I measure only one of them (i.e. when both "read volts" and "read curr" VI:s are inside the while loop compared to when only one of the VI:s are inside the while loop).

What is the sample rate lower when I measure two channels, and can I do this differently to measure both channels simultaneously, and still have a high sample rate?

thank You

[Dennis_Knutson]

Why wouldn't the sample rate decrease? For one measurement, you send a command to the instrument to take a measurement and then retrieve the data. This takes x amount of time. You then send an almost identical command and read the results. This is going to take x amount of time as well. There may be some slight differences in the time it takes the instrument to perform a voltage measurement and a current measurement but probably not enough to notice.

Whether or not the instrument is capable of doing simultaneous measurements is something I don't know. You will have to read the manual to see whether you can set it up for this. With some instruments, you setup the measurement types and when you ant to perform it, issue an initiate command and do a Fetch for each reading. Certain instruments differentiate between a MEAS?, READ?, and a FETCH? A MEAS? command will usually force the instrument to initiate a new measurement each time and a Fetch? will only tell the instrument to send the current data. I don't have an Amrel any more and I can't download the driver so I'm not sure what the driver is using.