YOKOGAWA UP35A, User Manual

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10-26
IM 05P02D41-01EN
10.15 Using 15 V DC Loop Power Supply
Description
The 15 V DC loop power supply is a function to supply DC power (14.5 to 18.0 V DC (21
mA DC)) to a 2-wire transmitter.
The loop power supply block is isolated from the controller’s internal circuitry. In addition,
the block is equipped with a current limiting circuit. Therefore, accidental short-circuits
that may occur in the field do not adversely affect the rest of the controller’s internal
circuitry.
Note that the loop power supply function cannot be used for digital communication where
the supply voltage is superposed on the signal line.
The following shows the examples of loop power supply connection to a 2-wire
transmitter.
2-wire transmitter
100 Ω
0.4-2 V DC
Controller