SIEMENS SM3xx LED Activity

A simple question from a SIEMENS newbie!

I have removed a S7 300 system from its cabinet in the industrial application environment and wish to monitor/program in a more comfortable environment.

I have connected the PS307 power supply to the CPU315-2DP via the comb connector and have connected the CPU, DO, DI and AI modules together via the bus connector 720 2001-01.

The program appears to run but there is no LED activity on the DO/DI/AI signal modules - do I need to connect external power to the signal modules' front connectors to have LED indication of status?

I can monitor via Monitor/Modify VATables but would prefer to have status indication at the signal modules - I recall from experience of AB programmable IO modules that this was standard practice for development/testing.

CPU diagnostics show OB122 has been invoked several times and each time address P256 is mentioned - no further diagnotics present.

SF LED is lit but this was also the case on site.

I can't find any simple text on these aspects on the SIEMENS website/documentation and am waiting on their support to contact me on Monday.

Anyone wish to throw some light on this issue?

TodHead said:

A simple question from a SIEMENS newbie!

The program appears to run but there is no LED activity on the DO/DI/AI signal modules - do I need to connect external power to the signal modules' front connectors to have LED indication of status?

Click to expand...

Some IO card requires supply voltage to enable operation. You'll find the supply connection diagrams on the back of the 'doors' on the cards.

I'll recommend you to remove all error-OB's. Then you should fix all errors until it runs stable.

Kalle

SIEMENS SM3Mxx LED Activity

Thanks, Kalle, for your help,

There is indeed a wiring diagram on the back of the doors and I have also unearthed some documentation with more complete diagrams of the signal modules.

By supplying 24VDC/0VDC from PSU to appropriate front connector terminals I now have LED activity on DI and DO modules.

The Diagnostic buffer of CPU 315-2 DP gives ten (and only ten)identical Events:
Event ID 16# 2941
I/O access error, reading P area,
double word access, Access address: 256
Priority class: 1
External error, Incomimg event
Time hh:mm:ss Date YYY-MM-DD


Could this be related to the AI module?

The rack is CPU 315-2DP, SM322 32xDO, SM321 32xDI, SM331 8xAI.

TodHead said:

The Diagnostic buffer of CPU 315-2 DP gives ten (and only ten)identical Events:
Event ID 16# 2941
I/O access error, reading P area,
double word access, Access address: 256
Priority class: 1
External error, Incomimg event
Time hh:mm:ss Date YYY-MM-DD


Could this be related to the AI module?

Click to expand...

Yes.
If you pick out the AI-card you'll find 4 coding bricks on the side. They are used to select the type of AI signal to read. (0/4-20mA, mV, +-10V ...). You must triple chedk that these are set as assigned in the HW-manager.

Kalle

TodHead said:

The Diagnostic buffer of CPU 315-2 DP gives ten (and only ten)identical Events:
Event ID 16# 2941
I/O access error, reading P area,
double word access, Access address: 256
Priority class: 1
External error, Incomimg event
Time hh:mm:ss Date YYY-MM-DD

Click to expand...

Unusual to see a double word access for an analogue module.

The I/O access error means that when the CPU attempted to fetch data from peripheral addresses 256..259, the module did not respond.

Open the h/w config from Simatic Manager by double clicking on Hardware:

The h/w config will show the modules and their addresses. Note that there are two panes and you may have to drag the dividing line to view the bottom pane.

Click on the Online/Offline button to change to Online

Double click on the analogue module to display any online module diagnostic information. (I'm using PLCSIM for these screen shots so there is no real h/w)

KalleOlsen and L D[AR2,P#0.0]: Thanks for your assistance so far on this, it has greatly helped my understanding - I hope to be able to reciprocate some day!

I think the OB122 problem may be related to absence of 24VDC/0VDC supply to AI module and I will first be in a position to check this tomorrow AM and will update on findings.

Have a nice (1/2) weekend!