How to Convert TTL Signals to NPN/PNP and Vice Versa

Your question is not asking the right question or its not giving the right information. TTL and NPN are using transistors. What you are trying to do sounds very easy but I am unclear as to what you are asking.

You need to use TTL compatible Prox switches with a TTL input card. For example and source to order, see http://www.fargocontrols.com/sensors.html

What is the model number and make of the proximity switch?

NPN/PNP are not signals they silicon configurations of a transistor, TTL (Transistor to Transistor Logic) is a digital signal of 5V for 1 and 0V for 0. I'm guessing that in the case of NPN the output of the proximity switch is open collector referenced to 0V, if this is the case the collector will need to be "tied up" via a resistor (or a relay?) to the 5V rail of the "device which accepts / sends out TTL signals" and connected to the input, the the 0V of this device will also need to be connected to the proximity switch. With an open collector PNP output the collector would need to be tied to 0V with the 5V connected to the proximity switch. The question is a little vague but I've done my best to answer with the info you've given.

TTL output in status 1 should be (low is up to 1.4v and high is1.7 to5v)and the npn and pnp is reverse and forward bising ability.

so these transister just let pass the voltage train thorugh the diplation lyer if the collector is -(npn) or +pnp .

and the proximity are exectly similar to transister(just passing the voltage -tiv with npn

and +tiv with pnp.

and the metal(or object with in the sensing range) will work as base function .

just take the TTL signal out and use a transister to oprate the relay (for the proximity input voltage) and use the other relay at the output of the proximity and bring the relay contacts in between of TTL signal.so the TTL signal will be processed with isolation.

i hope it will work

The now ancient logic family of TTL (here is a link to the 7400 NAND gate) uses NPN transistors to build the logic function. If you look at the interface part (the input and output) of the schematic for the gate found on page three of the link, you will see the TTL input (an emitter that requires current to flow to ground for a "0" input). You will also see two NPN transistors that get turned ON one at a time. One transistor produces a logic "0", while the other produces a logic "1". Now if you look at your sensor paperwork and cannot see how to produce a "1" or "0" with this sensor to connect to a TTL input, then you have two options:

1. Post here the sensor schematic, the manufacturer's name and part number, a link to either of these or at the very least the text of what the sensor wiring interface. I or somebody else will quickly draw a schematic for you.

2. Put the soldering iron down.

Unless your sensor was fabricated specifically for some fixed logic level voltage that does not match the TTL +5V level (+24V PLC, -6V ECL, +12~15 Automotive, etc.), you will not require anything more than a resistor to connect sensor with TTL. If your proximity sensor does work on any of these voltages, a simple interface can be designed here. But without knowing what sensor you have, I cannot help you.

The sensor is SUNX-CY22 (NPN). I am not able to figure out how to produce a '1' or '0'.

Ok, just to verify. Is this the manual for your part and is page 7 the I/O wiring for your NPN output circuitry? If this is your sensor, then you will have to provide the sensor with a separate +10V to +30V supply voltage (+V) for successful operation, with the +V attached to the brown wire and the supply's return (RTN) gets attached to the blue wire. (I'm expecting that your TTL circuitry may only have +5V available.) Now for your TTL connection the same blue wire RTN node gets connected to the TTL return or ground. The black wire gets connected to your TTL input. That should do you, but you might be susceptible to some noise. The easiest thing to reduce noise sensitivity would be connect a pull up resistor of say a nominal 5.1K 1/4 watt resistor across the TTL available +5V supply and the TTL input node.

(If you really need a schematic, I'll draft one after the Holidays. Merry Christmas. Hic.)

Oh I almost forgot. This interface description will permit connection to just the TTL circuit, not an additional relay. To wire in the relay, you have to give people at least a hint what relay and will you be wiring to the relay's contacts or driving the relay's coil. This will likely require a simple schematic diagram.

Merry Christmas. _{Where's my egg nog.}

This is my sensor. Thanks and have a Merry Christmas!

This May Be of Use:

As I (nearly) Described HERE

NPN refers to a transistor that has a Negative Emitter, Positive Collector and Negative Base.(Hence NPN).Symbolically, it is represented with the arrow pointing out(Not Pointing iN).PNP is exactly opposite,hence PNP( Pointing iN).(a little mental pneumonics to help remember).

Now, TTL is Transistor/Transistor Logic.It is simply a square wave output.Raw input to TTL is usually filtered thru a Schmidt Trigger to clean it up to a nice neat square wave.

The ideal amplitude of the signal is usually from 0 to 5 volt, but in the real world, it has a slightly elevated zero to cancel out any low level noise that may creep in,and allow for turn on bias of the transistors.

The scaling of the output into usable units is a function of the input/output board and display/driver or computer interface card.

You switch should work fine as a signal source if you observe the polarity mentioned above.

HTH

HTRN

Hmmm... Negative Base? The base emitter junction of an NPN transistor is basically a forward biased diode which is a PN junction. Although your description of the schematic works.

Opto 22, gordos, potter brumfield and others make a family of units which is just what you are looking for:

AC to TTL = IAC

DC to TTL = IDC

these are input devices

TTL to AC = OAC (5 A at 120 (240?))

TTL to DC = ODC (5A )

these are your outputs

all of these companies also have boards for installing and wiring and are quite simple

These units have been used in industry for 15 + years they are colour coded for function RED, Black, White, and Yellow. Best of all they are optically isolated to about 1000 V.

If you only need one or two I have soldered right on to the pin leads (but this makes it harder to replace if one happens to fail)