DrDAQ external input

oao · Post by **oao** » Wed Jan 24, 2007 3:35 pm

I'm trying to connect to the DrDAQ external input. I understand that the manual shows the pin numbers from left looking towards the card, component side up. Using the PicoScope I observe noise when I touch pin 3 (Auto detect) but not when I touch pin 1 (signal). The Y-axis is set to Ext1 x1.

When I connect a 1.5V battery between pin 1 and 2 I see no change in the scope trace (stays at zero), when I connect 3 and 2 I get a reading of about 100. I do not use a auto scale resistor.

I have two questions: Do I understand the no 1 pin position of the external connector correctly?

Why do I get a reading of 100 when the input voltage is about 1.5V?

ziko · Post by **ziko** » Tue Jan 30, 2007 3:33 pm

Hi and thank you for your post.

If you want to measure a voltage, you would connect between V and Gnd, pin 1 and 4 (4 closest to parallel connector)

Pin 1 is for voltage measurements
Pin 2 is for Resistance
Pin 3 is a Digital output which can be activated if you write your own software.
Pin 4 is ground

Kind regards