Siemens SIMATIC S7-400H - Diagnostics of a CPU 41 Xh Operating as PROFIBUS DP Master; Table 7- 2 Meaning of the BUSF LED of the CPU 41 X Operating as DP Master; Table 7- 3 Reading out the Diagnostics Information with STEP 7

PROFIBUS DP
7.1 CPU 41x–H as PROFIBUS DP master
S7-400H
System Manual, 03/2012, A5E00267695-11
91
7.1.3 Diagnostics of a CPU 41xH operating as PROFIBUS DP master
Diagnostics using LEDs
The following table shows the meaning of the BUSF LEDs. Always the BUSF LED assigned
to the interface configured as PROFIBUS DP interface lights up or flashes when a problem
occurs.
Table 7- 2 Meaning of the "BUSF" LED of the CPU 41x operating as DP master
BUSF Meaning What to do
Off Configuration correct;
all configured slaves are addressable
-
Lit
 DP interface error
 Different Baud rates in multi-DP master
operation (only in stand-alone mode)
 Evaluate the diagnosis. Reconfigure or correct the
configuration.
Flashes
 Station failure
 At least one of the assigned slaves is not
addressable
 Bus fault (physical fault)
 Check whether the bus cable is connected to the
CPU 41x or whether the bus is interrupted.
 Wait until the CPU 41x has powered up. If the LED does
not stop flashing, check the DP slaves or evaluate the
diagnosis of the DP slaves.
 Check whether the bus cable has a short-circuit or a
break.
Reading out the diagnostics information with STEP 7
Table 7- 3 Reading out the diagnostics information with STEP 7
DP master Block or tab in STEP 7 Application See ...
CPU 41x "DP slave diagnostics"
tab
Display the slave diagnosis as plain text on
the STEP 7 user interface
See "Hardware diagnostics" in
the STEP 7 Online Help, and
Configuring hardware and
connections with
STEP 7 in the
manual
SFC 13 "DPNRM_DG" Reading slave diagnostics data,
i.e. saving them to the data area of the user
program
The busy bit may not be set to "0" if an error
occurs while SFC 13 is being processed.
You should therefore check the RET_VAL
parameter whenever SFC 13 was
processed.
For information on the
configuration of a CPU 41x, refer
to the
CPU Data Reference
Manual ; for information on the
SFC, refer to the System and
Standard Functions Reference
Manual
. For information on the
configuration of other slaves,
refer to the corresponding
description
SFC 59 "RD_REC" Readout of data records of the S7 diagnosis
(saving them to the data area of the user
program)
Refer to the System and
Standard Functions Reference
Manual