Force Curves - is there a synch signal available?

Paul Farrar posted on Tue, Feb 19 2013 6:03 AM

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Hi

What I'm trying to do is run a succession of I-V sweeps during a standard force curve measurement so I can measure the I-V propeties of my sample at different separations and forces simultaneously. I know that within the software it is not possible to sweep both  Z and bias simultaneously but we have a signal access module so I wanted to supply an external voltage sweep to the stage and measure the TUNA output whilst a force curve measurement is running. The main problem I'm having is synching the voltage sweep with the Z movement. Ideally I would apply the sweep for every point on the force-displacement curve, but at this stage I cannot find a signal to synchronise to when the force curve is started. Does anybody know of a signal I could use to trigger my external sweep with the piezo sweep?

I've checked the end of frame and end of line synch signals on the back of our controller but these do not seem to be active in force mode. My only other thought is using the z-drive signal itself. The system I'm working on is a  Nanoscope IVa  Dimension 3100 with Extended TUNA module.

Thanks for reading

Paul