YOKOGAWA UT55A - 10.17 Using 15 V DC Loop Power Supply

10-33
IM 05P01C31-01EN
Output(ControlandRetransmission)Functions
10
10.17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