Interrupts, diagnostics messages, error and system alarms
6.1 Status and error display of the CM
CM 1542-5
24
Manual, 11/2014, C79000-G8976-C290-02
Meaning of the LED displays
The CM 1542-5 has 3 LEDs to display the current operating status and the diagnostics
status and these have the following meanings:
•
RUN/STOP LED
(one-color LED: green)
•
ERROR LED
(one-color LED: red)
•
MAINT LED
(one-color LED: yellow)
The following table shows the meaning of the various combinations of colors of the
RUN/STOP, ERROR and MAINT LEDs.
Table 6- 1
Meaning of the LEDs
RUN/STOP LED
ERROR LED
MAINT LED
Meaning
LED off
LED off
LED off
No supply voltage on the CM or supply
voltage too low.
LED lit green
LED lit red
LED lit yellow
LED test during startup
LED lit green
LED lit red
LED off
Startup (booting the CM)
LED lit green
LED off
LED off
CM is in RUN mode.
No disruptions
LED flashing
green
LED off
LED off
No CM configuration exists
Loading firmware
LED lit green
LED flashing red
LED off
A diagnostics event has occurred.
LED lit green
LED off
LED lit yellow
Maintenance, maintenance is demand-
ed.
LED lit green
LED off
LED flashing
yellow
Maintenance is required.
Downloading the user program
LED flashing
green
LED flashing red
LED flashing
yellow
Module fault
Diagnostics with LEDs
Diagnostics using the LEDs is the first means of narrowing down errors/faults. To narrow the
error/fault down even further, evaluate the message on the display of the S7-1500 CPU. If
errors/faults occur, you can also identify them using the Web server or by evaluating the
diagnostics buffer of the CPU. The diagnostics buffer of the CPU contains plain language
information about the error/fault that has occurred. The diagnostics buffer is accessible via
STEP 7, the display and the Web server.