Loop Impedance Meaning -- Data Logger Troubles
Loop Impedance Meaning -- Data Logger Troubles
(OP)
Hi!
I am trying to measure the voltage through a "DaqPro", basically a data logger. I've used a voltmeter to get a reading, but then when I use the DaqPro it's totally off. So my question is--what does loop impedance mean, especially if it reads:
(Input Channel Measure: 0 – 50.000 mV)
Range 0 to 50mV
Resolution 3µV
Accuracy ±0.5% of reading
Loop impedance - 50?
Please let me know if you understand!
I am trying to measure the voltage through a "DaqPro", basically a data logger. I've used a voltmeter to get a reading, but then when I use the DaqPro it's totally off. So my question is--what does loop impedance mean, especially if it reads:
(Input Channel Measure: 0 – 50.000 mV)
Range 0 to 50mV
Resolution 3µV
Accuracy ±0.5% of reading
Loop impedance - 50?
Please let me know if you understand!





RE: Loop Impedance Meaning -- Data Logger Troubles
See:
http://www
200K is still fairly high, but when compared to a typical Fluke DMM with 10Mohm input it seems low.
Could it be loading down the source of voltage you are trying to measure? What is the nature of the voltage source?
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"It's the questions that drive us"
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RE: Loop Impedance Meaning -- Data Logger Troubles
If it were loading down my voltage source (which I don't think it is), would a resistor help?
Thank you!!
RE: Loop Impedance Meaning -- Data Logger Troubles
RE: Loop Impedance Meaning -- Data Logger Troubles
It may not be a typo, if you check the data logger tab
It says 50 ohm input. The spec. sheet (pdf) seems to
leave the input impedance off.
RE: Loop Impedance Meaning -- Data Logger Troubles
I don't understand the difference between loop impedance and input impedance. Does loop pertain to simply the resistance/impedance throughout the circuit? And does input mean the impedance just from the mixer?
RE: Loop Impedance Meaning -- Data Logger Troubles
This all assumes a 200K input. What you actually have will become evident with this experiment.
RE: Loop Impedance Meaning -- Data Logger Troubles
A loop impedance of 50 ohms may be typical of a current loop.
Each device in a current loop will have a fairly low impedance. The current loop will have a maximum impedance value. The maximum impedance value of a current loop is determined by the voltage of the loop power supply.
Are you sure that your module is not intended for use with a current shunt?
respectfully
RE: Loop Impedance Meaning -- Data Logger Troubles
RE: Loop Impedance Meaning -- Data Logger Troubles
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"It's the questions that drive us"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
RE: Loop Impedance Meaning -- Data Logger Troubles