sinking vs. Sourcing few facts , are these right ?

[danishdeshmuk]

sinking vs. Sourcing few facts , are these right ?

1) Sinking (Refers for NPN sensors , NPN Switches) : Means they produce -ve output , they provide -ve (ground / common) .... Right ?

2) If its N.O NPN sensor then it means , whenever it sense any thing or object it would produce the -ve (ground / common) of the output .... and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

3) If its N.C NPN sensor then it means , whenever it doesn't sense any thing or object it would produce the -ve (ground / common) of the output .... and whenever it senses then no output and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

4) For N.O NPN output to PLC module the PLC module should be DC and should be a Sinking DC Module for compatibility issues , we can not use Sourcing PLC module for this kinda designing , Right ?

5) For any relay or contactor contact , we would provide directly + ve 24 Vdc to the coil of relay or to the coil of contactor and when the output of N.O NPN sensor i.e. -ve (ground / common) comes the relay or contactor energizes and it switches the load ....... Right ?

6) Sourcing (Refers for PNP sensors , PNP Switches) : Means they produce +ve output , they provide +ve supply mostly 24 Vdc .... Right ?

7) If its N.O PNP sensor then it means , whenever it sense any thing or object it would produce the + ve supply of the output .... and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

8) If its N.C PNP sensor then it means , whenever it doesn't sense any thing or object it would produce the + ve supply of the output ....and whenever it senses then no output and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

9) For N.O PNP output to PLC module the PLC module should be DC and should be a Sourcing DC Module for compatibility issues , we can not use Sinking PLC module for this kinda designing , Right ?

10) For any relay or contactor contact , we would provide directly -ve (ground / common) to the coil of relay or to the coil of contactor and when the output of N.O PNP sensor i.e. + ve 24 Vdc comes the relay or contactor energizes and it switches the load ....... Right ?


thanks

 

[rfredel]

Hello danishdeshmuk

1) Sinking (Refers for NPN sensors , NPN Switches) : Means they produce -ve output , they provide -ve (ground / common) .... Right ?

Sinking means, that when the output transistor is on, the output is low voltage. In the attached pictures you see circuit one which delivers only an output voltage, and circuit two is an open collector where you can directly connect a relais or contactor. If S1 (S2) is open, T1 (T2) is open too. So Vout = Vce goes to low level. After S1 (S2) is closed, the transistors are also closed and no current flows through.

2) If its N.O NPN sensor then it means , whenever it sense any thing or object it would produce the -ve (ground / common) of the output .... and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

Yes, that's right. Without signal Vout is high and the Relais is off.

3) If its N.C NPN sensor then it means , whenever it doesn't sense any thing or object it would produce the -ve (ground / common) of the output .... and whenever it senses then no output and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

Yes, you are right. Without signal Vout is low and the relais is off, but the the contact is close.

4) For N.O NPN output to PLC module the PLC module should be DC and should be a Sinking DC Module for compatibility issues , we can not use Sourcing PLC module for this kinda designing , Right ?

PLC modules with DC input is OK. N.O. sensor modules with voltage output can connect directly. If you have open collector output you need a pull up resistor or an input as a source.

5) For any relay or contactor contact , we would provide directly + ve 24 Vdc to the coil of relay or to the coil of contactor and when the output of N.O NPN sensor i.e. -ve (ground / common) comes the relay or contactor energizes and it switches the load ....... Right ?

Yes, it's right. Look for picture 2 of Sensor N.O. Don't forget the freerunning diode.

6) Sourcing (Refers for PNP sensors , PNP Switches) : Means they produce +ve output , they provide +ve supply mostly 24 Vdc .... Right ?

7) If its N.O PNP sensor then it means , whenever it sense any thing or object it would produce the + ve supply of the output .... and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

8) If its N.C PNP sensor then it means , whenever it doesn't sense any thing or object it would produce the + ve supply of the output ....and whenever it senses then no output and normally we use this output for switching purposes for any relay contact or for any contactor contact or for any PLC module ...... Right ?

9) For N.O PNP output to PLC module the PLC module should be DC and should be a Sourcing DC Module for compatibility issues , we can not use Sinking PLC module for this kinda designing , Right ?

10) For any relay or contactor contact , we would provide directly -ve (ground / common) to the coil of relay or to the coil of contactor and when the output of N.O PNP sensor i.e. + ve 24 Vdc comes the relay or contactor energizes and it switches the load ....... Right ?

Not specially. You don't know, what type of transistor is inside the sensor. Look what I write above, what voltage is at the output.

I hope it helps.

Regards

Rainer

 

[danishdeshmuk]

Hello danishdeshmuk


Sinking means, that when the output transistor is on, the output is low voltage. In the attached pictures you see circuit one which delivers only an output voltage, and circuit two is an open collector where you can directly connect a relais or contactor. If S1 (S2) is open, T1 (T2) is open too. So Vout = Vce goes to low level. After S1 (S2) is closed, the transistors are also closed and no current flows through.

Yes, that's right. Without signal Vout is high and the Relais is off.

Yes, you are right. Without signal Vout is low and the relais is off, but the the contact is close.

PLC modules with DC input is OK. N.O. sensor modules with voltage output can connect directly. If you have open collector output you need a pull up resistor or an input as a source.



Yes, it's right. Look for picture 2 of Sensor N.O. Don't forget the freerunning diode.



Not specially. You don't know, what type of transistor is inside the sensor. Look what I write above, what voltage is at the output.

I hope it helps.

Regards

Rainer

Questions 6,7,8,9 & 10 are yet to be answer . Their answers are still remaining.

 

[rfredel]

Hello danishdeshmuk,

What you write in Q 6 to 10 is right, but not dependent from the transistors.

You don't know, what transistors are inside the sensor. The output you get is only dependent of your logic.

If you need "active low logic" the output change from high to low, when the sensor sense anything.

For "activ high logic the output change from low to high, when the sensor sense anything.

Both can make with NPN or PNP transistors. So must not know what is the output transistor.

Regards

Rainer

 

[alexan_e]

sinking vs. Sourcing few facts , are these right ?

1) Sinking (Refers for NPN sensors , NPN Switches) : Means they produce -ve output , they provide -ve (ground / common) .... Right ?

5) For any relay or contactor contact , we would provide directly + ve 24 Vdc to the coil of relay or to the coil of contactor and when the output of N.O NPN sensor i.e. -ve (ground / common) comes the relay or contactor energizes and it switches the load ....... Right ?

A NPN can either sink or source current depending on the configuration used, it can also drive a relay both ways



In the emitter follower circuit (emitter as output) the voltage is related to the base voltage , the emitter will be 0.6v lower that the base voltage, this means that even if you have 12v or 24v supply to the collector if you drive the base with 5v you will get 4.4v at the emitter.

 

[danishdeshmuk]

Hello danishdeshmuk,

What you write in Q 6 to 10 is right, but not dependent from the transistors.

You don't know, what transistors are inside the sensor. The output you get is only dependent of your logic.

If you need "active low logic" the output change from high to low, when the sensor sense anything.

For "activ high logic the output change from low to high, when the sensor sense anything.

Both can make with NPN or PNP transistors. So must not know what is the output transistor.

Regards

Rainer

But how to get to know that inside the sensor which configuration is used with the transistor ?

What actually this tells NPN N.O sensor (NPN N.O mentioned/printed on the surface/body of the sensor) ?

Can we find this out by measuring the output with DMM ?

 

[Tunelabguy]

But how to get to know that inside the sensor which configuration is used with the transistor ?

What actually this tells NPN N.O sensor (NPN N.O mentioned/printed on the surface/body of the sensor) ?

Can we find this out by measuring the output with DMM ?

No, it is indistinguishable. Why would you need to know anyway? If you are just using the sensor then it is not necessary to know if the sensor is implemented with PNP or NPN or MOSFETs or relays. All that matters is what current will be coming in our out of the sensor and at what voltage.