Keithley 2401 source-meter (r)

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John Larkin 14 years ago

Well, after my fiasco with their Chinese rebrand 2100 DVMs, I should have known better than to buy another Keithley anything.

I figured a source-meter would be good to have, so I got a 2401. $3000 mistake.

The user interface is terrible.

The VF display is bad, so I thought I had the current limit set to 1 amp, but it was actually 1 uA, because the "u" doesn't work. The "A" flashes intermittently.

If it's programmed to make 10.000 volts, it's pretty good after it warms up for a half hour or so. But if you grab one of the insulated test leads, local EMI seems to get into it, and you can make the voltage go down to 9.8.

It does have a CE mark on the back, so it should have been EMI tested. Hmmmmm.

Back it goes.

John Larkin, President Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation

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Klaus Kragelund 14 years ago

I have one of those at my desk.

As you said really confusing user interface. Annoying beeps, defaults to turned on, so every time I use it I have to go through menu items to shut it off, or my colleagues will shut me off.

It has very good precision and fast settle (at least mine has). But, we have had our share of problems. At one time, using it in current sourced mode, the voltage reading of the display was offset by over

100mV, not even a fixed number. Guess what Keithley told us, download new firmware. Of course that did not do any good.

The fan runs fast and noise, allthough we use it for units that needs only a couple of 100 mW....

As for the driver for Labwindows. It won't let you read back the voltage, eve resorting to SCPI commands does not resolve that issue. Had to add a DMM to monitor the voltage when using it in a automated setup.

Regards

Klaus

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Spehro Pefhany 14 years ago

How much engineering do you think would be involved in doing something like that RIGHT?

With all the dubious stuff being thrown on the market, I'm beginning to smell a market opportunity for a mid-high-end manufacturer using good hardware and software designs while leveraging modern production techniques.

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

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John Larkin 14 years ago

I would really like a super-precise voltage source that's easy to use and program. It doesn't seem like that would be really difficult. The power part would be a coarse-fine DAC driving a power opamp. A 24-bit delta-sigma ADC could do local/remote sense and close the loop. All you need then is a good reference and a simple user interface. It becomes a ppm-class DC DVM for free.

Any firmware jocks out there want to work on this? I can do the hardware.

The Keithley has a zillion pushbuttons on the front, and didn't obviously make much sense to me. Other people say it's buggy as regards remote control and LabView. But the EMI thing was the real killer.

John Larkin, President Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators

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Keithley 2401 source-meter (r)

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