Din rail Optocoupler

[engineer1000]

Hi, I need to isolate a couple of inputs using a din rail optocoupler. My question is I assume I need to fit series resistor to the input of the opto as you would with a standard pcb opto , what is the normal way of fitting a resistor to a din rail mounted opto ?

 

[FvM]

DIN rail optocpouplers are usually designed to work with standard control voltage in automation systems, e.g. 24V and don't need external ersistorr. Why don't you read a datasheet?

 

[D.A.(Tony)Stewart]

ANywhere in series, if none is included. Depending on opto CTR to bias 1V input IR diode with series R to meet product spec , use Ohm's Law to choose R with drive voltage minus 1V for IR LED and draw required current.

E.g. 8.5mA from 5V to Opto +
5-1= 4V 4V/8.5mA = 470 Ω R in series. for low level drive.

Or... 0V to Opto - input and high level drive ( inverted to above) with 5V logic and 470R in series.
Logic often has 50R internal series R so 420Ω external R will result in desired input current to achieve maximum out rated current ( e.g. 100mA) of DIN device.

 

[engineer1000]

DIN rail optocpouplers are usually designed to work with standard control voltage in automation systems, e.g. 24V and don't need external ersistorr. Why don't you read a datasheet?

The data sheet isn't actually very clear **broken link removed**. It states a nominal control current of 7ma . It doesn't mention a urrent limiting resistor anywere and the schematic drawings don't have one either

 

[FvM]

The data sheet isn't actually very clear

I can't imagine it to be much clearer

Rated control voltage: 24 V DC ±20 %