Wiring input sensors – Rockwell Automation 1794-OB16D FLEX I/O Diagnostic Modules User Manual User Manual
Page 22
Publication 1794-UM061A-EN-P - July 2006
20 About the FLEX I/O Diagnostic Input Module
Wiring Input Sensors
You must use a 1794-TB32 or 1794-TB32S terminal base unit with the
1794-IB16D diagnostic input module. See installation instructions
ldkg df;l
for complete information.
Two-wire input devices connect to the input and sensor power terminals;
3-wire devices use input, sensor power and common terminals. You can wire
2-wire and 3-wire sensors to the FLEX I/O 1794-TB32 or 1794-TB32S
terminal base units.
Unused sensor-power ports or open-contact input devices must use a dummy
resistor to mask the diagnostic function. If these external resistors are not
used, the module’s fault indicator will light, along with the module’s error bits,
thus rendering fault detection of the remaining channels useless. The
recommended value of this dummy resistor is 20 k
Ω
(+10%), 1/8 Watt (or
larger). Connect the resistor between sensor power and input signal or
between sensor power and common.
17 1
8
19 20 21 22 23 24 25 26 27 2
8
29 30 31 32 33
0 1 2 3 4 5 6 7
8
9 10 11 12 13 14 15
16
35 36 37 3
8
39 40 41 42 43 44 45 46 47 4
8
49 50 51
34
COM1
N
C
Sensor Common and User Po
w
er Common:
Inp
u
t Channels 0-15
N
C
Sensor Po
w
er Terminals for Channels 0-15
+
V
1 COM1 +
V
1 COM1 +
V
1 COM1 +
V
1
+
V
2 COM2 +
V
2 COM2 +
V
2 COM2 +
V
2 COM2
N
C
Terminals C-36, C-3
8
, C-40, C-42, C-44, C-46, C-4
8
and C-50.
User po
w
er (+)
V
oltage: Terminals C-43, C-45, C-47 and C-49
+
V
1 Terminals C-35, C-37, C-39 and C-41 are not
u
sed
N
C
COM1 and COM2 are connected together in the mod
u
le.
A
B
C
0 1 2 3 4 5 6 7
8
9 10 11 12 13 14 15
0 1 2 3 4 5 6 7
8
9 10 11 12 13 14 15