Rockwell Automation 1771-IND series C INSTL INSTR AC/DC INPUT MODULE - Manual (Page 10)

10 Digital ac/dc (24V) Input Module
Publication 1771-IN052B-EN-P - April 2006
Troubleshoot with the Status Indicators
The front panel of your module contains 1 green
module-active indicator, and 16 red status indicators. The
1771-IND/C input module performs diagnostics in a
handshaking mode when first powered up. Upon
successful completion of the diagnostics, the green
module-active indicator lights. It turns off if a fault occurs
in the data paths or the opto-isolators.
If a module-fault occurs, the module resets its inputs or
sets them to last state, depending on the fault mode
selection. The module-active indicator must be on to
properly interpret the red status indicators.
The red status indicators are provided for system
logic-side indication of individual inputs. When a red
indicator lights, voltage is present on the terminal. The module transfers this information to
the backplane for the processor to read.
Use this table to help you interpret the 1771-IND/C input module-status indicators and to
troubleshoot module and system faults.
Indicator Status
(Color) Description of Fault or System
Status Action to Take
Module Active On
(Green) Normal indication None
Module Active On
(Green) and Input
Status ON (Red) Check for voltage on terminal If no voltage, replace module.
Module Active On
(Green) and Input
Status Off Input devices not functioning properly
or faulty input circuitry on module 1. Check input devices.
2. If power supplies are OK, replace module.
No voltage on terminal None
Module Active Off Module is not powered or fault in
opto-isolators, data paths or both;
module resets inputs or goes to last
state 1. Check chassis power supply and module
input power.
2. If power supplies are OK, replace module.
Module Active Off
and Input Status On
(Red) or Off Not valid unless module active
indicator is on; when active is off,
indicators do not represent processor
status 1. Check chassis power supply and module
input power.
2. If power supplies are OK, replace module.
ACTIVE
00
01
02
03
04
05
06
07
10
11
12
13
14
15
16
17
Module-active
Indicator (green)
00 to 17 Status
Indicators (red)
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