Connection to an AC supply. Vaisala DMP248

C HAPTER 3 _______________________________________________________________ INSTALLATION

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 shortcircuit. To avoid this, always use separate floating supply for each transmitter (see F IGURE 3-18 A). However, if several transmitters have to share one transformer, the phase (

∼

) must always be connected to + connector in each transmitter (see F IGURE 3-18 B).

A) NO COMMON LOOP FORMED - RECOMMENDED

DMP248 transmitter Controller

24 VAC

24 VAC

B) COMMON LOOP FORMED - NOT RECOMMENDED!

DMP248 transmitter

Controller

24 VAC

DMP248 transmitter shared common line

F IGURE 3-18

DMP248 transmitter

Connecting the transmitter to an AC supply.

V AISALA _________________________________________________________________________ 23