Siemens S7-1200 PROFIBUS - DP Slave Diagnostics Data and Standard Diagnostics

Diagnostics and upkeep
5.1 Diagnostics
SIMATIC CM 1242-5
32 Operating Instructions, 01/2023, C79000-G8976-C245-06
5.1.2 DP slave diagnostics
Diagnostics data depending on the protocol version of the DP slave
Depending on the type of configuration, the CM 1242-5 operates either as a DP-V1 slave or as
a DP-V0 slave, see also section Configuration (Page 27). Depending on this, the diagnostics
data is transferred to the DP master in different ways:
• As DP-V1 slave: Diagnostics interrupt
Transfer of the diagnostics data as a diagnostics interrupt Diagnostics interrupts must be
acknowledged by the DP master
• As DP-V0 slave: Diagnostics alarm
Transfer of the diagnostics data as a diagnostics alarm Diagnostics alarms are not
acknowledged by the DP master.
Supported diagnostics functions
The CM 1242-5 supports the following blocks of DP diagnostics:
• Standard diagnostics (6 bytes)
• Device-specific diagnostics (6 bytes)
Depending on whether a DP-V1 or DP-V0 slave is involved, there are differences in the
data of the device-specific diagnostics.
User program (DP master)
To read out the diagnostics data of the DP slave (DP single diagnostics), use the "DPNRM_DG"
instruction on the DP master.
Diagnostics interrupts of DP-V1 slaves are evaluated in the user program of the master using
the "RALRM" instruction.
You will find the required parameter assignment for the instructions in the STEP 7 online
help.
Below, there is an overview of the structure of the diagnostics data.
Overview of standard diagnostics
Standard diagnostics
Byte
Meaning
0
Station status 1
1
Station status 2
2
Station status 3
3
Master address
4...5
Vendor ID of the slave