Hi Bob,
Thanks for your answer. I have designed another schematic to solve my problems.
(Please visit the site to view this file)
Please help me check.
The 4-20mA signal must have a return path. --> I don't known what is this, because my sensor just have 2 wire, 1 wire for 24VDC source, 1 wire for 4 - 20mA signal. Could you send me an example about return path of the 4-20mA signal ?
Thanks and best regards,