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ZenHacker

Member Since 29 Feb 2012
Offline Last Active Mar 19 2016 01:07 PM
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#43602 Sick Photoelectric Sensor to Netduino Plus 2

Posted by ZenHacker on 17 January 2013 - 01:37 PM

I would have to agree with Paul on the "Rubbish Datasheet" comment.  Personally, I would expect to see at least some portion of the internal circuitry at a minimum.  I have used Sensors from Panasonic (NAiS, SunX, etc.) and for the most part their datasheets do show at least the basic transistor, Zener, reverse polarity diodes, internal pull-up[dn], etc. Even if it does not include the exact component part (part#), a basic internals diagram goes a long way to help me hook things up with less loss of magic smoke.

 

When bridging the gap between Industrial use sensors and microcontroller TTL or LVTTL levels I stay away from PNP generally and use NPN.  PNP in the general context of “Industrial” refers to Sourcing outputs (Closing to V+[L+]) and NPN is Sinking output (closing to GND, 0V [or M]).

 

The sensor you list is PNP, meaning that when the sensor is “made”, depending on mode Lite-On (output active if reflected light is seen at sensor), or Dark-On (output is active if light is “blocked” from Sensor) [L/D], In either case, as previously stated the output [Q, pin 4] on this sensor will be either 0V or VS-1.8V, in other words, if powered at 10VDC you will have 8.2VDC to deal with before putting it into any of the Netduino inputs (Voltage divider with 3.3v Zener perhaps, or Opto-Isolator).

 

 

In general when I use industrial type sensors I just stick with NPN (Open Collector, Sinking, etc.)  the sensor can be powered from any source (per it’s spec, 10-30V, whatever).  The output signal is only closing to 0V so if your sensor supply 0V/GND were common to the Netduino Gnd, you could use a pull-up resistor to 3.3v from the Netduino and wire into one of the Netduino Inputs.  This has the effect of inverting the signal.

 

 

Best Regards,

Patrick




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