Endress+Hauser RIA15 - Page 6

RIA15
6 Endress+Hauser
Circuit diagram / Description
Multidrop 2-wire
sensors with process
display unit and LPS,
with backlighting
R
s
DC
1
2
3
I
Y
Y
I
Y
I
LED
- +
A0019722
1 Sensors
2 Power supply
3 HART® resistance
2-wire sensor with
process display unit
and active barrier
RN221N as LPS
Y
I
1
2
3
O+
O-
RN221N
R
s
R
LED
- +
A0019576
1 Sensor
2 HART® primary master
3 HART® resistance
The HART® communication resistance of 230 Ω in the signal line is always necessary in the
case of a low-impedance power supply. It must be installed between the power supply and the
display unit.
A HART® communication resistance module is available as an accessory →  13.