@matt.spencer wrote:
I am attempting to use the standard library single point read to measure current. Everything is working fine except that it is way too slow for our application. The 34401 datasheet says it can read 1000 readings / second and store 512 readings in memory.
we are getting about 3 readings / sec. I tried the Read (Multiple Points) to see if it was faster and I am still getting about 3 reads per second.
What can be done to speed this up? I would like at least 20-30 reads per second
Thanks
With Auto Zero and NPLC both at the default settings you will get exactly 3 Reading per second if your primary power is 60Hz
10 power line cycles to integrate a "Zero Reading" followed by 10 PLC to integrate the current reading.
Options:
- Reduce the NPLC to 1 the reading will necessarilly get noisier since there is less time to average out 60 cycle hum. At very low currents the Power Line noise may be significant. How "Accurate" do you need the measurement? Result: 30Readings per second
- Change AZero to "once" to use the same zero reading and take multiple readings. The readings may lose acuracy due to thermal drift of the current sensor but "Self Heating" is likely a non-factor at that low of a current. Result: 5 * 1/ NPLC Readings per second
- If the device is in a controlled enviornment with a very stable temperature and proper airflow, is provided to the instrument (Clean the Fans!) you may chose AZero of off. Absolute accuracy will be reduced but any deltas will be unaffected. Result: 6 * 1/ NPLC Readings per second
"Should be" isn't "Is" -Jay
