Siemens S7-1200 - Page 785

Online and diagnostic tools
14.1 Status LEDs
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
785
If the defect-mode restart fails, (for example, due to a hardware fault), the STOP and
ERROR LEDs are ON and the MAINT LED is OFF.
WARNING
Operation in defect state cannot be guaranteed
Control devices can fail in an unsafe condition, resulting in unexpected operation of
controlled equipment. Such unexpected operations could result in death or serious injury to
personnel, and/or damage to equipment.
Use an emergency stop function, electromechanical overrides or other redundant
safeguards that are independent of the PLC.
Status LEDs on an SM
In addition, each digital SM provides a DIAG LED that indicates the status of the module:
● Green indicates that the module is operational
● Red indicates that the module is defective or non-operational
Each analog SM provides an I/O Channel LED for each of the analog inputs and outputs.
● Green indicates that the channel has been configured and is active
● Red indicates an error condition of the individual analog input or output
In addition, each analog SM provides a DIAG LED that indicates the status of the module:
● Green indicates that the module is operational
● Red indicates that the module is defective or non-operational
The SM detects the presence or absence of power to the module (field-side power, if
required).
Table 14- 2 Status LEDs for a signal module (SM)
Description
DIAG
(Red / Green)
I/O Channel
(Red / Green)
Field-side power is off
Flashing red
Flashing red
Not configured or update in progress
Flashing green
Off
Module configured with no errors
On (green)
On (green)
Error condition
Flashing red
-
I/O error (with diagnostics enabled)
-
Flashing red
I/O error (with diagnostics disabled)
-
On (green)