Keithley 6517B electrometer as a V-source measuring at the same time the current I or voltage V

[VGH]

I made some modifications to your VI and made it work. However, the data acquisition rate is limitted to about 15 Hz. Is there a way to improve this rate? [per Keithley's Data Sheet the Max Acq. speed should be ~ 500 Hz] I have set the 6517B to continiousl trigger mode with a trigger timing of 0.01 PLC. Both filtering and math functions are disabled to improve the response. Despite all this the speed is low. Any help would be appreciated....

I have attached a copy of the modified VI as a reference.

VGH

[theInfiniteOne]

Hello I fond your example and am missing the: 

1. Keithley 6517 Zero Check.vi

2. GPIB Send Message.vi

Can you please show me where to find these two, or post them or email me at delacresse@gmail.com.

This utility would be vital to my work. Thank you.

[jaimenieto]

Apologies I have nothing to offer on the topic. Instead I would like to know how you communicate with the Keithley.

[VGH]

Hello, that was a long time ago. I initially tried to use the GPIB port, and the NI GPIB-USB-HS. But as I remember this was too slow and could not handle the speed I needed [GPIB command overhead for single reads is too high]. Another option was to have the device acquire and accumulate the data in its internal memory at 1 ks/s and once complete one could stream the data from internal memory to the PC via GPIB-USB. This worked but it was not compatible with my requirements. 

The solution I chose was to use my NI 16-bit USB-6259 ADC to acquire the measurements from the scaled analog output port of the Keithley 6517B.  This approach was much easier to implement, and the acquisition speed was much faster. Although at lower currents (e.g., pA ) higher acquisition bandwidth reduces signal to noise ratio.