Vaisala HMD70 - Manual (Page 10)

HMD70U/Y Transmitters
Operating Manual
U303en-1.1
6 1997-07-31
3.4.1 Connection to an AC supply
The HMD70U/Y transmitters can also be connected to an AC supply without
an external rectifier. However, when more than one transmitter is connected to
one AC transformer, a common loop is formed and there is an increased risk
of a short-circuit. To avoid this, use a separate floating supply for each
transmitter (see Figure 3.4.1.1). However, if several transmitters have to share
one transformer, the phase (
∼
) must always be connected to Us connector in
each transmitter (see Figure 3.4.1.1).
HMD70U/Y transmitter
Controller
VAC
VAC
Us
GND
signal
RH/T
GND
Us RH/T
signal
HMD70U/Y transmitter
HMD70U/Y transmitter
HMD70U/Y transmitter
Controller
shared
common line
VAC
GND
GND
Us
Us
RH/T
RH/T
signal
signal
Figure 3.4.1.1 Connection to an AC supply