Good morning,

I have a problem with a DT80. I have a potentiometer and I want to measure the voltage drop across it. I have a external source with 9V connect to potentiometer.

I take the measurement between the positive terminal of the source and the central terminal of potentiometer. I would have to obtain a measure of 4,5V but the measure that I obtain in the datataker is 2V approximately.

I'm using HV type and analog channel. When I decrease the voltage of the source under 3V and using the non-attenuation, the voltage measured in the dataTaker is correctly.

My problem is produced when I increased the source over 3V. How can I obtain correct measure if the measure is over 3V?

Thank you

Good afternoon rexking,

What is the resistance value of the potentiometer? You probably have a high resistance potentiometer and in combination with the attenuation resistors is forming a Voltage divider.

Cheers,
Roger

The resistance value is 500 kΩ, but is adjust in the middle of range approximately.

Good afternoon rexking,

I just tried this myself. I think you are short circuiting the battery and it doesn't have the current to drive the Voltage I connected to a power supply (12 VDC @100 mA) and got the following:

1V 3313.7248 mV
1HV 3.3125 V

1V 99999.9 mV
1HV 3.3237 V

The reading just before the over range is within about a mV. The code used was

RA1S 1V(FF4) 1HV(FF4)

Try putting a large resistor in circuit to limit the current.

Cheers,
Roger