Siemens Simatic S7-300 CPU 31xC Series - Status and Error Displays of All Cpus

Debugging functions, diagnostics and troubleshooting
10.6 Diagnostics using status and error LEDs
S7-300, CPU 31xC and CPU 31x: Installation
10-10 Operating Instructions, Edition 08/2004, A5E00105492-05
10.6.2 Status and error displays of all CPUs
Table 10-2 Status and error displays
LED Meaning
SF 5 VDC FRCE RUN STOP
Off Off Off Off Off CPU power supply missing.
Remedy: Check whether the power supply module is
connected to mains and switched on.
Off On X (see the
description)
Off On The CPU is in STOP mode.
Remedy: Start the CPU.
On On X Off On The CPU is in STOP mode as a result of error.
Remedy: refer to the tables below, evaluation of the SF
LED
X On X Off Flashes
(0.5 Hz)
The CPU requests memory reset.
X On X Off Flashes
(2 Hz)
The CPU executes memory reset.
X On X Flashes
(2 Hz)
On The CPU is in startup mode.
X On X Flashes
(0.5 Hz)
On The CPU was halted by a programmed break point.
For details, refer to the Programming Manual
Programming
with STEP 7 .
On On X X X Hardware or software error
Remedy: refer to the tables below, evaluation of the SF
LED
X X On X X You enabled the Force function
For details refer to the Programming Manual
Programming
with STEP 7 .
X X Flashes (2 Hz) X X Node flashing test was activated.
Flashes Flashes Flashes Flashes Flashes Your CPU has an internal system error. The procedure is
as follows:
1. Set the mode selector switch to STOP.
2. Perform POWER ON/OFF.
3. Read the diagnostics buffer with STEP 7.
4. Contact your local SIEMENS partner.
Description of status X:
This status is irrelevant for the current CPU function.
Reference
• Details on the OBs and on SFCs required for their evaluation can be found in the STEP 7
Online Help
and in the Manual System Software for S7-300/400 - System and Standard
Functions
.