PNP Inductive Sensor

[maddoctor90]

You can run an external circuit to power the 12V sensor and not use the digital sidecar power. You will then need to attach a pull down resistor between the signal going into the sidecar and ground. See the pull down resister configuration in http://en.wikipedia.org/wiki/Pull-up_resistor for more information on what I am talking about. The sidecar is simply an IO interface to the 9403 module. Thus the data sheet here http://www.ni.com/pdf/manuals/374069e.pdf will tell you that you the module is protected for up to +- 30 Volts. The AB photo sensors (npn) available from FIRST Choice will feed 12 volts signal into the digital sidecar and I have not heard of any teams having any problems with them, so I think you will be fine feeding a 12V signal to your digital sidecar. In fact, we are currently using a 12 volt PNP prox using the configuration I just described. I would like to comment though, if you use a 12V sensor and your battery voltage drops below 12V, the sensor will turn off. Also, you need to make sure not to have your pull down resistor (a custom circuit) off of the same breaker powering the sensor, as this would be a violation of R47.

[Alan Anderson]

Originally Posted by maddoctor90

You can run an external circuit to power the 12V sensor and not use the digital sidecar power. You will then need to attach a pull down resistor between the signal going into the sidecar and ground. See the pull down resister configuration in http://en.wikipedia.org/wiki/Pull-up_resistor for more information on what I am talking about. The sidecar is simply an IO interface to the 9403 module. Thus the data sheet here http://www.ni.com/pdf/manuals/374069e.pdf will tell you that you the module is protected for up to +- 30 Volts.

There is a 10k resistor from each DIO signal pin to the Digital Sidecar's 5V supply. Connecting 12V to that pin is not recommended.

The AB photo sensors (npn) available from FIRST Choice will feed 12 volts signal into the digital sidecar and I have not heard of any teams having any problems with them, so I think you will be fine feeding a 12V signal to your digital sidecar.

The NPN sensors do not source any voltage at all, much less 12 volts. They are the equivalent of a simple switch that is either open-circuit or closed to the power return (ground). That's basically what the Digital Sidecar was designed to connect to.

In fact, we are currently using a 12 volt PNP prox using the configuration I just described. I would like to comment though, if you use a 12V sensor and your battery voltage drops below 12V, the sensor will turn off.

The 12V optical sensors provided in the 2011 Kit of Parts will work down to at least 10.5V. Some nominally 12V sensors are spec'd to function at 9V.

Also, you need to make sure not to have your pull down resistor (a custom circuit) off of the same breaker powering the sensor, as this would be a violation of R47.

Can you explain why you believe <R47> applies to a pull-down resistor in a custom circuit?