Endress+Hauser RIA15 - Wiring with Switchable Backlighting

RIA15 Wiring
Endress+Hauser 27
6.4 Wiring with switchable backlighting
An additional current-limited current source is required to implement switchable
backlighting, e.g. active barrier RN221N. This current source is used to supply the LED
backlighting of up to 7 RIA15 process display units without causing an additional voltage
drop in the measurement loop. The backlighting can be switched on and off using an
external switch.
The following shows connection examples for the hazardous area. Wiring is similar
for the non-hazardous area; however, it is not necessary to use Ex-certified devices.
6.4.1 Connection diagram for one process display unit
LED
- +
-
+
I
Y
1
+
-
O-
L
N
PE
O+
7
6
5
+
-
O-
L
N
PE
O+
8
4
2
3
9
10
A0028248
1 Process display unit RIA15
2 3-wire connector, e.g. WAGO 221 series
3 2-wire sensor
4 Terminal block on top-hat rail
5 Active barrier, e.g. RN221N
6 4 to 20 mA output to the control unit
7 Power supply
8 Current source, e.g. RN221N
9 Switch to activate backlighting
10 Power supply