Stream Mode gain and post-log scaling | LabJack

Stream Mode gain and post-log scaling

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Matthew Teears
mteears's picture
Stream Mode gain and post-log scaling

To give you some background into what I'm trying to use the U6 Pro for...

I'm trying to measure current by using a 10 ohm shunt resistor on a product to determine its current usage over a period of time.  Periodically the product will come on and transmit for approximately 8-14ms.  I want to record that transmission pulse with as much accuracy as possible.  The currents that I will be measuring vary from 1uA to 12mA.  I'm having trouble deciding what gain level to use on the U6 because of the time required at the higher gains.  

My question is...  When I use the gain function of the LabJack U6, do I have to divide my resulting number by the gain, or is the number automatically scaled for me?

I may be back for more questions... Thanks ahead of time!

LabJack Support
labjack support's picture
The voltage readings you get

The voltage readings you get are the actual voltage at the terminal.  The U6 internally accounts for amplification.

I would consider dropping your shunt value a little so your max voltage is 100mV or less and you can then use the +/-0.1 range.

A low-side shunt is generally preferred.  If you are doing a differential measurement with a high-side shunt make sure your signals are not floating versus the U6 and make sure your common-mode voltage is valid: