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617 thermal drift

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Joined: October 21st, 2010, 2:03 pm
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617 thermal drift

Post by igorfier » February 9th, 2011, 2:03 am


How can I overcome warmup thermal drift in a 617 unit?
It has been powered up 20 hours ago, and measuring current through a 10 kOhm resistor alone, placed inside a vacuum cryostat (in thermal equilibrium). It started measuring ~2 pA and now it's measuring ~50 pA, still growing! The room temperature is being kept constant at ~23 °C.

Also, are there any means to make this unit to properly respond an "*IDN?" call from GPIB?
This would make my life easier interfacing this instrument!

Best regards,

Igor Fier

Tom Sw
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Re: 617 thermal drift

Post by Tom Sw » February 9th, 2011, 4:26 am

The 617 has been obsolete for over 10 years so I'm not sure there's much we can suggest. We still offer repair and calibration services if you feel there is something wrong with the instrument.

As far as the remote interface, it's documented in the manual which is still on our website. I do not believe *idn? is supported.

Dale C
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Re: 617 thermal drift

Post by Dale C » February 9th, 2011, 5:27 am

The Model 617 is a DDC instrument (Device Dependent Command) and does not respond to SPCI commands.
You can find these DDC commands in the instruction manual. Here is the link.
The Model 617 should not have more than 5fA(5e-15A) of offset or drift when warmed up for one hour.
If there is more offset or drift than the 5fA then the unit is in need of service.

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