I am trying to make a 4-20mA control loop on a home made sensor that will connect to a PLC. I was using Texas Instruments XTR111AIDGQR, but it is too expensive, costing $1.72. so want to try switching it out with WS2801, an LED driver that costs $0.13.
The LED driver documentation says it has a wide output current range up to 150mA, which can be adjustable to the LED current. I limited the current to 20mA using a 30ohm resistor as shown in the diagram below. I will use the TWI (Two Wire Interface) to "Dim" the 20mA current.
Will this application work? Am I not considering something that will make this not work?