Siemens S7-300 appendix Status and error displays of the CPU, General status and error displays

Operating and display elements 2.2 Operating and display elements: CPU 31x

2.2.4Status and error displays of the CPU 31x

General status and error displays

Table 2-6	General status and error displays of the CPU 31x
LED designation		Color	Meaning
SF		red	Hardware or software error.
DC5V		green	5-V power for the CPU and the S7-300 bus
FRCE		yellow	LED is lit: Active force job
			LED flashes at 2 Hz: Node flash test function (only CPUs with
			firmware V2.2.0 or higher)
RUN		green	CPU in RUN
			The LED flashes during STARTUP at a rate of 2 Hz, and in HOLD
			state at 0.5 Hz.
STOP		yellow	CPU in STOP, or HOLD, or STARTUP
			The LED flashes at 0.5 Hz when the CPU requests a memory reset,
			and during the reset at 2 Hz.

Displays for the X1 and X2 interfaces

Table 2-7	Bus error displays of CPU 31x
CPU		LED designation	Color	Meaning
315-2 DP		BF	red	Bus error at DP interface (X2)
317-2 DP		BF1	red	Bus error at interface 1 (X1)
		BF2	red	Bus error at interface 2 (X1)
31x-2 PN/DP		BF1	red	Bus error at interface 1 (X1)
		BF2	red	Bus error at interface 2 (X1)
		LINK	green	Active communication at interface 2 (X2).
		RX/TX	yellow	Receive / Transmit data at interface 2 (X2)

Reference

•CPU operating modes: STEP 7 Online Help.

•Information on CPU memory reset: Operating instructions CPU 31xC and CPU31x, Commissioning, Commissioning Modules, CP Memory Reset by means of Mode Selector Switch

•Evaluation of the LEDs upon error or diagnostic event: Operating Instructions CPU 31xC and CPU 31x, Test Functions, Diagnostics and Troubleshooting, Diagnostics with the help of Status and Error LEDs

CPU 31xC and CPU 31x, Technical data	2-11
Manual, Edition 08/2004, A5E00105475-05