Author Topic: Example Project: 20 Channel solid state scan card for K2000 DMM  (Read 362 times)

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Offline voltsandjolts

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I have previously posted a 10 channel armature scan card here:
https://www.eevblog.com/forum/circuit-studio/example-project-relay-scan-card-for-k2000-dmm/

I needed more channels for a particular job where a little SSR channel leakage wouldn't be a problem, here is the result.
It's been tested in K2000 and DMM6500.
It's switchable, 10 or 20 channels; some 2000 series gear might only support 10 channels (?), and saves some money if you only need 10 channels.
Initially I thought my K2000 would only support 10 channels but to my surprise the 20 channel card is supported too - at least it is in the latest firmware.

The PIC MCU firmware has a known issue when using with a DMM6500.
Switching between 2W and 4W resistance on the same channel causes the channel relay to open.
It works fine changing between channels in 2W and 4W.
I just need voltage measurements so didn't spend time fixing it, there's a note in the firmware source.

Thanks to forum members alm and cozdas for providing some background information and inspiration.
« Last Edit: June 21, 2020, 01:16:10 pm by voltsandjolts »
 
The following users thanked this post: KedasProbe, thm_w, edevaldo

Offline voltsandjolts

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Re: Example Project: 20 Channel solid state scan card for K2000 DMM
« Reply #1 on: June 20, 2020, 06:51:32 pm »
CircuitStudio Project attached in 7-Zip format

 


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