Industrial light sensor on PIFACE

I have found that documentation that show your sensor is the "With Time delay, diffuse light" sensor type.

http://www.idec.com/language/english/datasheet/SA1U_datasheet.pdf

It's labeled SA1U-D01MT on the docs.

Take into account "diffuse light" sensors may be proximity sensors that works on reflection of light emmited so it may not be a "light" sensor at all http://www.balluff.com/balluff/MUS/en/products/Diffuse-sensors.jsp

You should first check what kind of sensor is yours, to know if it works on light emmited from a external source - light sensor - or the reflection of light emmited by itself - proximity / pressence / fill sensor.

From what it's seen on docs, it have a couple of output types, transistor - NPN and PNP - and relay. The transistor is the row with 2 screws where the "TIme delay" knob is, and the relay it's the row with 3 screws where that knob is.

It also have a selector with different operation modes near those screws - search for "Operation Chart" on the documentation for its meaning. I would put it on 0 - zero - that's "Light ON - Normal Mode" - there are One shot and delay modes as well - so you know the sensor will be "on" when it detects light, with no delays, and no special functions.

The easier way to use it I guess it will be with the relay - three screws - if timing - and I am talking on the ms mark - is not important to you.

If you have a multimeter - they are cheap and if you want to fiddle with electronics you will need one - you can check the continuity - electrical connection - in the relay pins. Search for "Terminal Arrangement" on the documentation  to see a graphic with the relay terminals numbered.

There should be continuity on pins 5 and 4 with the sensor disconnected and no continuity on pins 4 and 3. Look for "Output Circuit / Connection Diagram" on the documentation for an explanation on the internal connection of the output terminals-

When powered up, if it detects light pins 4 and 3 will be connected. If not they will be disconnected. Pins 5 and 4 will have the opposite output - connection on light off, disconnection on light on.

The first ting I would do is to power up the device and check the voltage on the 3, 4 and 5 screws. It must be 0V. After that put the multimeter on continuity mode and "turn on" the light - or put something close to it. There must be continuity on pins 4 and 3. Check voltage again must be 0V. "Turn off" the light - or get something far from it - there must be no continuity on pins 4 and 3.

If all this works as intended, connect the 0V terminal from your PiFace to screw 4 on the sensor , connect screw 3 to one of the PiFace input pins. Remember, if you connect 5V instead of 0V your Pi could be in danger. Check with extra care this step. The PiFace detects a connection to ground that's why we connect ground - 0V - to the sensor's relay, and back to the input pin. That way we will connect the PiFace input pin to ground when light is on, and it will be detected by your PiFace.

Recheck that everything is as I said and the models on the docs and yours are the same.

I downloaded the docs from here http://www.newark.com/idec/sa1u-d01mwt/sensor-photo-diffuse-1m/dp/46T9538 check that model is yours.

Take your time and recheck all steps, it's important to check the voltage in the relay pins, if there is voltage the device may be faulty and I would not connect my Pi to it. In the other hand, the device is much more expensive than a Pi so may be for you to repurpose it is worth a fried Pi.

Anyway, go ahead at your own risk.

Hope this helps.

Notes:

In this text "pin", and "terminal" mean the connection screws to make electrical contact on the PiFace and the sensor.

More info on time delay funcions for the "Operation Chart" meaning http://www.macromatic.com/blog/understanding-time-delay-relay-functions/

More on multimeters http://en.wikipedia.org/wiki/Multimeter

What is continuity http://en.wikipedia.org/wiki/Continuity_test

More on relays http://en.wikipedia.org/wiki/Relay

I have found that documentation that show your sensor is the "With Time delay, diffuse light" sensor type.

http://www.idec.com/language/english/datasheet/SA1U_datasheet.pdf

It's labeled SA1U-D01MT on the docs.

Take into account "diffuse light" sensors may be proximity sensors that works on reflection of light emmited so it may not be a "light" sensor at all http://www.balluff.com/balluff/MUS/en/products/Diffuse-sensors.jsp

You should first check what kind of sensor is yours, to know if it works on light emmited from a external source - light sensor - or the reflection of light emmited by itself - proximity / pressence / fill sensor.

From what it's seen on docs, it have a couple of output types, transistor - NPN and PNP - and relay. The transistor is the row with 2 screws where the "TIme delay" knob is, and the relay it's the row with 3 screws where that knob is.

It also have a selector with different operation modes near those screws - search for "Operation Chart" on the documentation for its meaning. I would put it on 0 - zero - that's "Light ON - Normal Mode" - there are One shot and delay modes as well - so you know the sensor will be "on" when it detects light, with no delays, and no special functions.

The easier way to use it I guess it will be with the relay - three screws - if timing - and I am talking on the ms mark - is not important to you.

If you have a multimeter - they are cheap and if you want to fiddle with electronics you will need one - you can check the continuity - electrical connection - in the relay pins. Search for "Terminal Arrangement" on the documentation  to see a graphic with the relay terminals numbered.

There should be continuity on pins 5 and 4 with the sensor disconnected and no continuity on pins 4 and 3. Look for "Output Circuit / Connection Diagram" on the documentation for an explanation on the internal connection of the output terminals-

When powered up, if it detects light pins 4 and 3 will be connected. If not they will be disconnected. Pins 5 and 4 will have the opposite output - connection on light off, disconnection on light on.

The first ting I would do is to power up the device and check the voltage on the 3, 4 and 5 screws. It must be 0V. After that put the multimeter on continuity mode and "turn on" the light - or put something close to it. There must be continuity on pins 4 and 3. Check voltage again must be 0V. "Turn off" the light - or get something far from it - there must be no continuity on pins 4 and 3.

If all this works as intended, connect the 0V terminal from your PiFace to screw 4 on the sensor , connect screw 3 to one of the PiFace input pins. Remember, if you connect 5V instead of 0V your Pi could be in danger. Check with extra care this step. The PiFace detects a connection to ground that's why we connect ground - 0V - to the sensor's relay, and back to the input pin. That way we will connect the PiFace input pin to ground when light is on, and it will be detected by your PiFace.

Recheck that everything is as I said and the models on the docs and yours are the same.

I downloaded the docs from here http://www.newark.com/idec/sa1u-d01mwt/sensor-photo-diffuse-1m/dp/46T9538 check that model is yours.

Take your time and recheck all steps, it's important to check the voltage in the relay pins, if there is voltage the device may be faulty and I would not connect my Pi to it. In the other hand, the device is much more expensive than a Pi so may be for you to repurpose it is worth a fried Pi.

Anyway, go ahead at your own risk.

Hope this helps.

Notes:

In this text "pin", and "terminal" mean the connection screws to make electrical contact on the PiFace and the sensor.

More info on time delay funcions for the "Operation Chart" meaning http://www.macromatic.com/blog/understanding-time-delay-relay-functions/

More on multimeters http://en.wikipedia.org/wiki/Multimeter

What is continuity http://en.wikipedia.org/wiki/Continuity_test

More on relays http://en.wikipedia.org/wiki/Relay

Dear Iago,

thank you very much for your kind answer. I should get it done now.

KR, Michael