4 wire proximity sensor to plc input - PLCS.net

jeii · March 13th, 2011, 03:43 AM

Hi. I'm trying to teach myself PLC's on a mitsubishi FX2N-16MR.
I have connected a 4 wire PNP proximity sensor as NO to my plc but it is not switching the output.

The indicator on the sensor shows that its working when it detects and i have connected the NO wire to my input and the NC wire to my 0V as per a wiring diagram i have.
My program simply has 1 NC input and 1 NO input connected to a respective output.

I feel that maybe i have not specified something in GX developer?

I am using a CQ35-25NPP-KC1 sensor.

Thankyou for your help, please excuse my naivety.

Tharon · March 13th, 2011, 05:42 AM

I would not attach the white wire to 0V. While sometimes the white wire is not used, it can be used as a NC output, or sometimes 0-10V or 4-20ma output, etc. Keep the wire taped off and not terminated on any terminal. What happens if you manually switch voltage to the input (using a jumper wire from 24V)?

ibora · March 13th, 2011, 05:46 AM

Quote:

Originally Posted by jeii

..NC wire to my 0V as per a wiring diagram i have..

You should disconnect NC wire from 0V. You should keep it free or connect to another input.

jeii · March 13th, 2011, 06:03 AM

Thanks for the response guys.
I have tried with the NC wire removed, and manualy switching on the input did not work either.
Also, i can see when in monitor mode that the X1 input is not being activated.

Tharon · March 13th, 2011, 06:10 AM

Does the indicator for the PLC input turn on?

jeii · March 13th, 2011, 06:13 AM

It doesnt.
Is there anything else i need to do to associate the sensor with the ladder program in Gx Developer?

Tharon · March 13th, 2011, 06:51 AM

You shouldn't. And I believe the PLC Input indicator should turn on regardless of whether or not it's addressed in the PLC program.

Do you have access to a voltmeter? Can you make sure that 24V is being supplied to the Input terminal?

Your picture shows the RUN indicator on the PLC is off. Is that just because the PLC is powered down when you took the picture?

BTalbot · March 13th, 2011, 06:59 AM

For PNP sensors you need to make sure the S/S terminal is connected to the 0V terminal

Tharon · March 13th, 2011, 08:46 AM

Quote:

Originally Posted by BTalbot

For PNP sensors you need to make sure the S/S terminal is connected to the 0V terminal

Oh. I was wondering where you connected the 24V common for the inputs.

jeii · March 14th, 2011, 02:22 AM

Thanks for your help guys, i should of realised this. Hopefully i will have a more complex problem next time..

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March 13th, 2011, 05:42 AM	#2
Tharon Member Join Date: Jan 2007 Location: Michigan Posts: 1,059	I would not attach the white wire to 0V. While sometimes the white wire is not used, it can be used as a NC output, or sometimes 0-10V or 4-20ma output, etc. Keep the wire taped off and not terminated on any terminal. What happens if you manually switch voltage to the input (using a jumper wire from 24V)?

March 13th, 2011, 06:03 AM	#4
jeii Member Join Date: Mar 2011 Location: Qld Posts: 4	Thanks for the response guys. I have tried with the NC wire removed, and manualy switching on the input did not work either. Also, i can see when in monitor mode that the X1 input is not being activated.

March 13th, 2011, 06:10 AM	#5
Tharon Member Join Date: Jan 2007 Location: Michigan Posts: 1,059	Does the indicator for the PLC input turn on?

March 13th, 2011, 06:13 AM	#6
jeii Member Join Date: Mar 2011 Location: Qld Posts: 4	It doesnt. Is there anything else i need to do to associate the sensor with the ladder program in Gx Developer?

March 13th, 2011, 06:51 AM	#7
Tharon Member Join Date: Jan 2007 Location: Michigan Posts: 1,059	You shouldn't. And I believe the PLC Input indicator should turn on regardless of whether or not it's addressed in the PLC program. Do you have access to a voltmeter? Can you make sure that 24V is being supplied to the Input terminal? Your picture shows the RUN indicator on the PLC is off. Is that just because the PLC is powered down when you took the picture?

March 13th, 2011, 06:59 AM	#8
BTalbot Member Join Date: Jul 2002 Location: New Jersey Posts: 237	For PNP sensors you need to make sure the S/S terminal is connected to the 0V terminal

March 14th, 2011, 02:22 AM	#10
jeii Member Join Date: Mar 2011 Location: Qld Posts: 4	Thanks for your help guys, i should of realised this. Hopefully i will have a more complex problem next time..

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