Below are the requirements for using the STEP 7 function "Prepare cable diagnostics" or the system function SFC103 "DP_TOPOL".
With the system function SFC103 "DP_TOPOL" you can trigger the "Prepare cable diagnostics" function from a STEP 7 program. A sample program is available in the manual "SIMATIC Diagnostic Repeater for PROFIBUS-DP" in Entry ID: 7915183.
S7 system requirements
The following S7-300 CPUs support system function SFC103:
* only CPUs with Firmware from V2.5.0
|CPU 319-3 PN/DP
If you do not want to trigger topology diagnostics via the CPU, but want to fetch the diagnostics data exclusively from the diagnostics repeater, you only need system function SFC59 or system function block SFB52. These are also implemented in the other current S7-300 CPUs.
The following S7-400 CPUs support system function SFC103:
|CPU 412-2 PCI
|CPU 414-4 H
|CPU 416-2 PCI
|CPU 417-4 H
You need firmware version 3.1 for the S7-400 CPUs if you want to trigger topology diagnostics using SFC103 via the CPU. This function corresponds to the "Prepare cable diagnostics" in STEP 7. If you want to fetch the diagnostics data exclusively from the diagnostics repeater, you only need system function SFC59. This is already implemented in previous versions. This means that in order to simply read diagnostics data you do not necessarily need a firmware update.
As from firmware version 3.0 of the S7-400 CPUs system function block SFB52 is implemented in addition to SFC59 for reading diagnostics data.
If you do not connect the PROFIBUS for the diagnostics repeater directly to the CPU interface, but via a CP, then to execute the "Prepare cable diagnostics" function it must be supported not only by the CPU but also by the CP.
The following S7-400 CPs support the "Prepare cable diagnostics" function:
|CP 433-5 Extended
PG/PC system requirements
Setting required in "Set PG/PC interface"
With the interface setting "CPxxxx(Auto)" it is not possible to measure the nodes on the PROFIBUS DP. You must the interface to "CPxxxx(PROFIBUS)".
Implementable communication processors
The interfaces Onboard-MPI for PG740, MPI-ISA Card (6ES7 793-2AA..-0AA0) and PC Adapter (USB and serial) do not support the "Prepare cable diagnostics" function.
If you start the function nevertheless in STEP 7, measuring is stopped after the monitoring time expires. In this case the status "Diagnostics stopped" is shown in STEP 7 plus the additional text "Time monitoring addressed".
The following interface cards support the "Prepare cable diagnostics" function on the PROFIBUS DP:
For triggering the "Prepare cable diagnostics" function that is supported as from 6ES7 972-0AB01-0XA0 you require at least STEP 7 version V5.2 with Service Pack 1. This Service Pack is available in Entry ID 16540057