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Keithley 2410 sweep time much longer than it should be

Models 2400, 2401, 2410, 2420, 2425, 2430, 2440, 6430
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themartianinvader
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Joined: September 19th, 2018, 11:32 am
Country: United States

Keithley 2410 sweep time much longer than it should be

Post by themartianinvader » September 19th, 2018, 11:36 am

Trying to write a vi to do a current-voltage sweep with Keithley 2410 hooked up to Labview with GPIB. The vi is attached, as well as screenshot. According to the manual, if I do not set a manual voltage setting time, and use default NPLC (1PLC), each voltage point should have 3ms automatic voltage setting time (with the current range I'm in), then come the measurement which is 1/60 s = 16.7 ms, so the measurement time for one data point should be 16.7 + 3 = 19.7 ms. However, when I run the program and read the time stamp, 100 data points takes 7.2s, which averages each data point takes 72 ms, which is significantly longer than it should. I triple checked the wiring to make sure everything is correct. Am I doing anything wrong here? Thanks a lot for your time!
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sweep measurement.vi
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Dale C
Keithley Applications
Keithley Applications
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Joined: June 10th, 2010, 6:22 am
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Re: Keithley 2410 sweep time much longer than it should be

Post by Dale C » January 22nd, 2019, 10:49 am

There are a number of parameters that affect the system speed.
1. NPLC- Number of Power Line Cycles. This is only part of the A/D conversion process. So 1PLC does not mean it will be 16.67msec per reading.
2. Ranging - Auto range can cause delays. For more precise timing use fixed range.
3. Auto Zero - Auto zero allows the A/D process to go through only the signal integrate and calculate phases. This is will speed thing up.
4. Filter - The digital filter will cause delays. for precise timing, disable the filter.
5. Source Delay - Set this to 0.0 seconds.
6. Display -The display can be disabled. I usually only do this after the system is running. Meaning while troubleshooting keep the display enabled.

Hope this helps.

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