how to realize More channels 4-20mA current loop output

[Henrik_Volkers]

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K C wrote:

Hi Candy,

According to Ohm's law (at least at this side of the world ) a current of 4-20mA through a 50Ohm resistor gives a voltage of 0.2 - 1V

Please explain your value of 10-50mV

I do not understand your second question. A accuracy of 0.3-0.4% is rather good I think for transmitters.

Message Edited by K C on 11-03-2008 08:34 AM

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KC,

the the input is 50Ohms MAX . ~2Ohm < 50 Ohm ...

 I didn't take a look into the datasheet,but maybe R_in=f(Ucc,f,T,Ri_signal)

[K C]

Hallo Henrik,

Maybe you are right, but most devices (sensors, transmitter, repeaters, barriers, etc)  I know with 0(4)-20mA I/O have a fixed resistance of 50 or 250Ohm.

But I am working in a small world

btw. who marked a empty post as a solution ? ?

[Candy Yu]

sorry,i don't know why it is empty,i wrote some,but can't appear.

[Candy Yu]

about that 10mV~50mV,i mean our products(voltage signal &current signal) resistance is 50 Ohm(max),but generally is much less 50 Ohm, and 4-20mA this series across the diode voltage general is 10mV~50mV. Candy

[DamienS]

As the previous user suggested you can use a TURCK IMS interface module. (some info on that here - http://www.clrwtr.com/blog.html )

You can also try an ABB/Entrelec or Weidmuller analog signal transmitter/converter (http://www.clrwtr.com/Weidmuller-Waveanalog-20LP-Signal-Conditioners.htm )

[Don-M]

The Weidmuller signal conditioner link that you have listed here was moved. Please use the following link instead for Weidmuller signal conditioning products.

http://www.clrwtr.com/Weidmuller-Signal-Conditioning.htm