Vaisala DMP248 - Connection to an AC Supply

CHAPTER 3_______________________________________________________________INSTALLATION
VAISALA _________________________________________________________________________ 23
Connection to an AC supply
The DMP248 transmitter can also be connected to an AC supply
without an external rectifier. However, when more than one
transmitter is connected for example to one 24 VAC transformer, a
common loop is formed and there is an increased risk of a short-
circuit. To avoid this, always use separate floating supply for each
transmitter (see FIGURE 3-18A). However, if several transmitters have
to share one transformer, the phase (∼) must always be connected to +
connector in each transmitter (see FIGURE 3-18 B).
24 VAC
Controller
shared
common
24 VAC
24 VAC
DMP248 transmitter Controller
B) COMMON LOOP FORMED -
NOT RECOMMENDED!
A) NO COMMON LOOP FORMED - RECOMMENDED
supply voltage
signal output
supply voltage
signal output
supply voltage
supply voltage
signal output
signal ou tput
line
DMP248 transmitter
DMP248 transmitter
DMP248 transmitter
FIGURE 3-18 Connecting the transmitter to an AC supply.