IO Board Status LEDs
Each I
2
C-bus IO board has three status LEDs; a green Normal, a yellow Waning, and a red
Fault indicator. The Normal LED may flash to show active communication.
CAN Bus
I/O Boards
I
2
C Bus
I/O Board
CAN Bus
I/O Board LEDs
I
2
C
Bus
I/O Board
LEDs
Figure 2-22 IO Board Status LEDs
In the illustration above, one I
2
C IO board is shown on the right. Two legacy CAN boards are
shown to the left. These boards have a number of additional status LEDs, described in the
section on
CAN IO Board
Information.
IO Board DI Mode Switch
Switch SW1 located at the top of the board near the front (connector end) controls the mode
setting for the on-board digital inputs (DIs). The switch sets the mode for all DI circuits on the
board (mixing of modes on a board is not supported). The available options are Default/Sink
(Mode 2) and Legacy (Mode 1) A diagram is printed on the back of each board showing the
setting. The Legacy option is designed to adjust for a non-standard configuration that may be
in use on some systems. The Mode switch should be set to Mode 2 unless instructed differently
by Siemens.
Electronic Compartment Component Descriptions and Maintenance Procedures
2.4 Analog and Digital IO
Maxum II Reference Manual
Manual, 7/2017, 2000596-001
57
