Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 530)

I/O Interface
Section 10A
10A-7
Each I/O interface device connected to the I/O ring has a fault indicator
(LED) located on it. Some examples of these indicators are shown in the
following figure. The fault indicators on the I/O devices will be lit
whenever there is a ring communication error.
Figure 10A.4
Fiber Optic Interface Device Fault Indicators
HPG Rear
Monochrome Operator
Color Operator Panel
Rear
A01 A02 A03 A04 A05 A06 A07 A08 A09 A10
B01 B02 B03 B04 B05 B06 B07 B08 B09 B10
A11 A12 A13 A14 A15 A16 B11 B12 B13 B14 B15 B16
High--density I/O
Digital (or Analog) I/O
Keyboard I/O
Ring Interface
11389-I
Push-button MTB I/O Panel
Panel
8500-1746I
I/O RING
ADAPTER
ALLEN-BRADLEY
acTIVE
ADAPTER
FAULT
I/O RING
FAULT
1771 I/O
Ring Adapter
10A.1.1
Fiber Optic Ring Device
Fault Indicators