Pico controller not sensing input

[dbennett]

Hi guys,

I have an AB pico controller that is not seeing a capacitive sensor on a particular input. The application was written for one sensor but a second one would like to be added. The first sensor is being read and is working properly on one input (I8), but when a second sensor is added to I9, for some reason it is not functioning properly. The sensors were switched to make sure that the sensors weren't faulty and they are working fine. I'm thinking that certain inputs need to be activated in order for them to be used but can't seem to find anything related to that in the manual or in the AB software. The Pico is the 1760-L18AWA-EX model and accepts 120V inputs.

Thanks

 

[bernie_carlton]

Is the problem failure to turn off (rather than turn on?)

Check the manual. I7 and I8 seem to have higher input current requirements than the other inputs. The manual suggests that these be used with devices with higher leakage current. They are more immune to false turn on because of their higher current requirements.

Two-wire proximity sensors have a residual off-state leakage current.
If this residual current is too high, the input may indicate the input is
ON when the device is actually off. Use inputs I7 and I8 for these types of input devices​

 

[dbennett]

That did the trick, thanks Bernie!

I just switched the 2nd input to I7 from I9