am using a proximity sensor to count events which gives 12V signal. how can i convert this to TTL signal to be used with counter of 6024E"

[bedi]

am using a proximity sensor to count events which gives 12V signal. how can i convert this to TTL signal to be used with counter of 6024E"

[JB]

A good solution is to use an optocopler because it will furthermore electrically separate both signals.

The output current of the proximity sensor must be high enough (10mA) to drive the optocopler. Therefore I recommend to use a type with PNP output.

You can adapt the value of the resistor for different input levels. R = (Uin - 2)/ 0.01
eg 2K2 for 24V

[Upgrading]

Thanks, JB.  This is really useful.

From JB's schematic, If I don't want to use voltage regulater for 5V supply, can we just simply use 5V from a DIO channel by forcing it to HI all the time?  If so, please suggest values of R and C for the TTL side.  The output current for my DIO (NI 9403) is about 2 mA.

[Henrik_Volkers]

The PCI-6024 connector have a +5V output (fused with 1A) , however If you use a DO choose one from P0.<X>, according to the spec they can drive 13mA and should run fine.

A bonus on using the DO is an additional possibility to gate the counter.

[Upgrading]

Thanks, Henrik.  I am about to try a optocoupler with 5V internal regulater (http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button...).  Anyway, I will try to drive from a DO too.

-Vasu