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I am using a relay to switch the 5vdc source from a 1054 frequency counter back to its positive input. The negative input is tied to the onboard ground. And there is a 4.7k ohm resistor between positive input and ground (pull-down). The displayed input frequency can be around 0.5hz or around 4h.z However, I am seeing wide ranges: 2 to 4hz and 3 to 9hz. I suspect I may have the wrong value for the resistor or may need to clean up the signal a bit.

BTW, I currently have the data interval at 1 second, and that has help[ed a bit.

Suggestions?

If it's a mechanical relay you might be seeing some contact bounce which would mess with the frequency signal.

mparadis wrote:If it's a mechanical relay you might be seeing some contact bounce which would mess with the frequency signal.

Indeed. This did the trick... Thanks.