Hi,

Generally, there is ways to get diagnose:

1 - Using the LEDs on the hardware (Page 24)

2 - Local error analysis using the display of the CPU S7-1500 (Page 25)

3 - Using STEP 7 V12 (Page 27)

4 - Remote diagnostics by means of the web server (Page 44)

5- Stationary system diagnostics using the HMI diagnostics view (Pg 51)

6 - By user program (Page 63)

All these ways are useful. If possible, I suggest the use as first choice the ways that are ready for use (LED, Display) or that could be easily configured (Web server and HMI diagnostic view).

The use of STEP 7 needs additional resources (PC and the software - obvious) and a minimal know how of the use of them.

In special, the Web/HMI object has the best relation costs/benefices: all diagnose information is available, the operation is intuitive, and the information is displayed in an easy understandable language (text direct, without code errors, etc.) and could be got with few mouse clicks.

I suggest to use diagnose by user program just in the cases that the other ways are not possible: when the user program needs the diagnose information to take some operation decision or when the customer should display diagnose spicily on HMI objects (for example motor icon) or on non SIMATIC HMI.

Diagnose by user program

There many, many ways to get diagnose from user program:

Using blocks:

- RDREC - includes error information on faulty modules
(Module ID or Identification of a central module / PROFINET IO could be read with data record 16#AFF0)(stay on manual but it is note yet avaliable in the product)

- RALRM - includes detailed information of diagnostics-capable modules(stay on manual but it is note yet avaliable in the product)
https://support.industry.siemens.com/tf/br/en/posts/126846/

- DPNRM_DG - reads the current diagnostics data of a DP slave (DP standard diagnostics)(stay on manual but it is note yet avaliable in the product)

- GEN_DIAG - generates diagnostic information, by user program (fe.g. imported by GSD devices)

- GET_DIAG - to provide diagnostic information, the module or submodule is selected (FAQ at http://support.automation.siemens.com/WW/view/en/75167627?Datakey=47071380) (TIP at https://www.automation.siemens.com/BR/tf/WW/en/Posts/93559#top)

- T_DIAG - provides diagnostic and status information on a connection (stay on manual but it is note yet avaliable in the product)

- RD_SINFO - reads the start information of the OB last called (https://www.automation.siemens.com/BR/tf/WW/en/Posts/93575#461812)

- LED - reads the status of the module LED
(/tf/WW/en/Posts/89477#442421)

- RST_EVOV - resets the event counter

- Get_IM_Data - reads the Information&Maintenance data of the CPU (stay on manual but it is note yet avaliable in the product)

- Transfer_IM_Data - transmits the Information&Maintenance data of the CPU(stay on manual but it is note yet avaliable in the product)

- Get_Name - Get a IO Device name
https://www.automation.siemens.com/BR/tf/WW/en/Posts/93272#top

- DeviceStates - outputs the device status
(/tf/WW/en/Posts/89486#442455)

- ModuleStates - outputs the module status
(/tf/WW/en/Posts/89490#442478)

The open cited manual gives just an overview of these blocks and refers to the online help
of STEP7 to get more information. While an “Application & Tools” about the topic doesn’t come, a doubt stays:

With so many ways to get diagnose, which block should be used?

My suggestion: keep the best relation “benefits/cost”, i.e. use the simplest way to get the only really necessary information.

In this way, the diagnostic bit set by in Device View is the best choose for the cases that you need to know if a HW is ok or not.

Other blocks that could give this simplified information: LED Device modules, DeviceStates, Module States.

For communication, you can use the error bit of the communications blocks or the TDIAG block.

If you need more detailed information about the type of the fault, the GET_DIAG is a good choice. If you need device specific diagnose data (i.e. data that vary from one device to other), then use RDREC, RALRM, DPNRM_DG, Get_IM_Data.

TIP: SFC51

Frequentily In S7-300/400 was get diagnostics with the use of SFC51. SFC51 could not be used in S7-1500. In the help online of STEP7 V12 is showed alternatives. See FAQ: http://support.automation.siemens.com/WW/view/en/68397488