convert pnp to npn signal for plc input - PLCS.net

jasonjaybird · March 30th, 2007, 05:33 PM

does anyone know how to convert a pnp signal to a npn? for a plc input.besides using a relay.

pyare · March 30th, 2007, 06:18 PM

npn is a common negative terminal to your outputs and inputs.

Joe_WaZoo · March 30th, 2007, 06:47 PM

This will do it for you, very easily too.

TURCK Smart Plug

Joe_WaZoo

abwiz · March 30th, 2007, 08:41 PM

What is wrong with using a relay? You could go with solid state or an opto if you are concerned with the usual downfalls of a standard relay.

The TURCK smart plug looks pretty neat but I bet it has a higher cost that you were anticipating.

abwiz · March 30th, 2007, 08:45 PM

Joe

What do those smart plugs cost, anyways?

rsdoran · March 30th, 2007, 08:53 PM

Search the site for "pull-up or pull-down" resistor, it can be done with one resistor. If a 3 wire device then just reverse the logic.

shanmu_gam · March 30th, 2007, 11:27 PM

connect ur ground signal thru a resistor with 1.2K,1/2 W with ur PNP signal and pull down to npn signal.reverse the logic in ur plc

Gerry M · April 1st, 2007, 08:03 PM

And, one other option:
ASI

I have also used a resistor with the logic inverted as the previous two posts have stated.

Joe_WaZoo · April 2nd, 2007, 08:39 PM

abwiz,

Sorry for the my delay. The Mrs. & I went to New Orleans for the weekend and she wouldn't let me take along my brain, I mean Laptop. The price on these Smart Plugs from TURCK is $48 and they have well over 50 in stock of each type. That maybe a little steep, but as always in this industry that we are in, everything is negotiable.

Thanks,
Joe_WaZoo

BITS N BYTES · April 3rd, 2007, 08:02 AM

I have used the Phoenix Contact DEK-TR/INV for many applications where invertering signals. Converts PNP to NPN and vice versa.

See attachment

John Gaunt · April 3rd, 2007, 06:26 PM

I generally simply use a pull up resistor and invert the state in the PLC.

If you want more sophistication use an opto isolator chip. A simple 6 legged I.C. If you want to you can mount it in a plastic enclosure available from most terminal suppliers. Even add a LED
to indicate status.

2004sk4 · April 3rd, 2007, 07:04 PM

I used one of the turck sensors npn to pnp sensors today. We ran completely out of pnp sensor that we use on the line. We had several npn sensors on the shelve they had all the rest of the same specs. I agree with you about the convertor is a little on the high side$ . The way i see it that putting a inline quick connector is alot faster then installing a relay to flip the state. I would much rather get complains about spending money vs complain about downtime anyday. I alway keep 1 of each on the shelve (npn to pnp) or (pnp to npn) We have alot of different equipment(us,european,australia,etc). You really never know what kind of sensor you will run into.

brandoncosta · February 23rd, 2011, 11:43 AM

I'd also recommend TURCK smart plugs. I think output converter version should fit your application, but it's a little more expensive at $54.50

March 30th, 2007, 05:33 PM	#1
jasonjaybird Member Join Date: Mar 2007 Location: ontario Posts: 1	convert pnp to npn signal for plc input does anyone know how to convert a pnp signal to a npn? for a plc input.besides using a relay.

March 30th, 2007, 06:18 PM	#2
pyare Member Join Date: Mar 2007 Location: suva Posts: 2	pnp to npn npn is a common negative terminal to your outputs and inputs.

March 30th, 2007, 06:47 PM	#3
Joe_WaZoo Lifetime Supporting Member Join Date: Oct 2006 Location: Murphy, TX Posts: 301	This will do it for you, very easily too. TURCK Smart Plug Joe_WaZoo __________________ TURCK Network I/O Guy, Banner Wireless knowledge, & Red Lion HMI stuff! Yes I am the techie geek for the local Rep Firm Automated Dynamics Corp covering the states of TX, OK, AR, LA, MS, part of TN, and a little bit of Mexico.

March 30th, 2007, 08:53 PM	#6
rsdoran Lifetime Supporting Member Join Date: Apr 2002 Location: Birmingham, AL Posts: 7,371	Search the site for "pull-up or pull-down" resistor, it can be done with one resistor. If a 3 wire device then just reverse the logic. __________________ http://www.patchn.com Industrial Electrical & Maintenance @ www.patchn.com "Tell me and I forget, show me and I remember, involve me and I understand."

April 2nd, 2007, 08:39 PM	#9
Joe_WaZoo Lifetime Supporting Member Join Date: Oct 2006 Location: Murphy, TX Posts: 301	abwiz, Sorry for the my delay. The Mrs. & I went to New Orleans for the weekend and she wouldn't let me take along my brain, I mean Laptop. The price on these Smart Plugs from TURCK is $48 and they have well over 50 in stock of each type. That maybe a little steep, but as always in this industry that we are in, everything is negotiable. Thanks, Joe_WaZoo __________________ TURCK Network I/O Guy, Banner Wireless knowledge, & Red Lion HMI stuff! Yes I am the techie geek for the local Rep Firm Automated Dynamics Corp covering the states of TX, OK, AR, LA, MS, part of TN, and a little bit of Mexico.



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March 30th, 2007, 08:41 PM	#4
abwiz Member Join Date: Nov 2005 Location: PA Posts: 196	What is wrong with using a relay? You could go with solid state or an opto if you are concerned with the usual downfalls of a standard relay. The TURCK smart plug looks pretty neat but I bet it has a higher cost that you were anticipating.

March 30th, 2007, 08:45 PM	#5
abwiz Member Join Date: Nov 2005 Location: PA Posts: 196	Joe What do those smart plugs cost, anyways?

March 30th, 2007, 11:27 PM	#7
shanmu_gam Member Join Date: Mar 2007 Location: CHENNAI Posts: 22	connect ur ground signal thru a resistor with 1.2K,1/2 W with ur PNP signal and pull down to npn signal.reverse the logic in ur plc

April 1st, 2007, 08:03 PM	#8
Gerry M Member Join Date: Jun 2004 Location: Auburn, NY Posts: 255	And, one other option: ASI I have also used a resistor with the logic inverted as the previous two posts have stated.

April 3rd, 2007, 06:26 PM	#11
John Gaunt Member Join Date: Nov 2004 Location: Tasmania, Australia Posts: 362	I generally simply use a pull up resistor and invert the state in the PLC. If you want more sophistication use an opto isolator chip. A simple 6 legged I.C. If you want to you can mount it in a plastic enclosure available from most terminal suppliers. Even add a LED to indicate status.

April 3rd, 2007, 07:04 PM	#12
2004sk4 Member Join Date: May 2005 Location: Georgia Posts: 172	I used one of the turck sensors npn to pnp sensors today. We ran completely out of pnp sensor that we use on the line. We had several npn sensors on the shelve they had all the rest of the same specs. I agree with you about the convertor is a little on the high side$ . The way i see it that putting a inline quick connector is alot faster then installing a relay to flip the state. I would much rather get complains about spending money vs complain about downtime anyday. I alway keep 1 of each on the shelve (npn to pnp) or (pnp to npn) We have alot of different equipment(us,european,australia,etc). You really never know what kind of sensor you will run into.

February 23rd, 2011, 11:43 AM	#13
brandoncosta Member Join Date: Feb 2011 Location: SLC Posts: 37	I'd also recommend TURCK smart plugs. I think output converter version should fit your application, but it's a little more expensive at $54.50

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