I'm looking to simulate for 0 - 20 ma signal for making a simple I/O board to test some programs.

My analog card has a 50ohm input resistance so i need to regulate the current going into the analog card. This is pretty easy if it was just one input i need to simulate. Just use a 1.5v battery with some resistor. However i need to simulate 4 input so a resistor network wouldn't work because if i change one current i'll affect the other 3. So IC guru could you please point me to the right chip that will enable me to regulate and adjust 4 independent current loop using 24V input. I would like some sort of current limiting feature so i won't go over 20 ma. Also would like to adjust using some sort of resistor pot that will give reasonable accurately between 0 and 20mA at 1 or 2 mA increments.

Any help is greatly appreciated

My analog card has a 50ohm input resistance so i need to regulate the current going into the analog card. This is pretty easy if it was just one input i need to simulate. Just use a 1.5v battery with some resistor. However i need to simulate 4 input so a resistor network wouldn't work because if i change one current i'll affect the other 3. So IC guru could you please point me to the right chip that will enable me to regulate and adjust 4 independent current loop using 24V input. I would like some sort of current limiting feature so i won't go over 20 ma. Also would like to adjust using some sort of resistor pot that will give reasonable accurately between 0 and 20mA at 1 or 2 mA increments.

Any help is greatly appreciated

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