LJTick-InAmp configure maximum gain of 1001 via shorting

3 posts / 0 new

Wed, 01/03/2018 - 08:27

fieryfire

Dear Labjack,

For the LJTick-InAmp accessory, i see that resistances R17 and R32 are left open. Is it possible to short the connections of R17 or R32 in order to achieve the maximum possible gain of 1001 instead of using a resistance of R100Ohm inorder to achieve this?

Thanks,

Vivin

Wed, 01/03/2018 - 10:19

LabJack Support

No, 0 ohms is not a valid

No, 0 ohms is not a valid resistance to have from RG+ to RG- on the AD623. The specified range is 100 to infinity:

http://www.analog.com/media/en/technical-documentation/data-sheets/AD623...

Also, note if you use RG=100 to get Gain=1001, you will get more output noise produced by the LJTIA itself. Likely you will get about 5 times the noise you get at Gain=201, so your signal-to-noise ratio will only improve if you can filter that noise out. The 24-bit sigma-delta converters on the U6-Pro and T7-Pro, for example, can likely filter out a good deal of this added noise.

Thu, 01/04/2018 - 01:32

fieryfire

Thank you for the response. I

Thank you for the response. I would not be able to use the 24-bit sigma-delta converters as the for the project i am doing requires a sampling frequency of 64 to 66 channels each with 1000Hz frequency