Without going into a long-winded dissertation, forget about using resistors. The differences in the "zero" point base (0 volts vs. 4 mA) and in how instrument designs handle voltages versus currents do not lend themselves to a simple conversion using only resistors.
A 0-5V/4-20mA signal conditioner can be bought for around $250. You will burn up that money in a heartbeat trying to configure and calibrate a homebrew resistor setup.
Re: 5VDC TO 4-20mA Conversion#129093 07/12/0411:54 AM07/12/0411:54 AM
5V/0.020A=250Ω, but it’s not usually that simple.
There is an offset problem for transducer output—below 1 volt, the current channel will treat the reading as zero, or as a signal error when under 4mA. A resistor may work with the right 4-20mA transducer output and 1-5V input channel.
Re: 5VDC TO 4-20mA Conversion#129094 07/10/0508:10 PM07/10/0508:10 PM
Robert, Are you sure that you need a conveter? Many 4-20ma inputs just use a 250 ohm resistot internal to convert the current to a voltage, and many have a setting that will change the input from 4-20 to 0-20. If both of these conditions are present, all you have to do is to remove the internal resistor and change the setting to 0-20ma. Don