ADC output oscillates
Posted: Fri Feb 27, 2009 3:08 pm
Hi
I wonder whether anyone can help me fix the following behavior I see with the 8/8/8 interface kit under both windows and LINUX with the 2.1 library.
When making measurements I get the correct value followed immediately by a bogus lower value. For example a temperature sensor would return 19 immediately followed by 15. The first value is correct, the second is bogus. I tried different temp sensors, different ports and did even raw ADC conversions. It's always the same, there is a correct measurement followed by a lower bogus value.
I don't know much about electronics and was thinking that maybe the supply volatge breaks in under a measurement but even with a USB hub I see this behavior.
Since the 2 values are so far apart I cannot put a simple threshold in place.
Maybe someone knows what is going on.
Thank you.
Ralf
P.S. Does the phidget run a firmware btw?
I wonder whether anyone can help me fix the following behavior I see with the 8/8/8 interface kit under both windows and LINUX with the 2.1 library.
When making measurements I get the correct value followed immediately by a bogus lower value. For example a temperature sensor would return 19 immediately followed by 15. The first value is correct, the second is bogus. I tried different temp sensors, different ports and did even raw ADC conversions. It's always the same, there is a correct measurement followed by a lower bogus value.
I don't know much about electronics and was thinking that maybe the supply volatge breaks in under a measurement but even with a USB hub I see this behavior.
Since the 2 values are so far apart I cannot put a simple threshold in place.
Maybe someone knows what is going on.
Thank you.
Ralf
P.S. Does the phidget run a firmware btw?