Analog Module SF LED Always On

[dwcy]

I work on S7-300. And there are some other I/O module. I download a simple program to CPU314, the SF LED on CPU is normal but all the SF LED on analog module turns on. I tryed just use CPU314 with one AI module,however the SF LED on AI module still turns on. Anybody know what what happen? My configuration as below:

Rack 0:
1: Power Supply (PS307 5A)
2: CPU314
3: IM365 (SEND)
4: CP341 (Modbus Master)
5: AI8 (DC24V)
6: AI8 (DC24V)
7: AO2 (DC24V)
8: DI32 (DC24V)
9: DI16 (DC24V)
10: DO32 (DC24V)
11: CP341 (Modbus Slave)

Rack 1:
1: Empty
2: Empty
3: IM365 (RECEIVE)
4: AI8 (DC24V)
5: AI8 (DC24V)

[dchartier]

Hello dwcy;

I would start by checking the 24 V DC power wiring on the module. There must be independant power to each analog module on the rack. If you don't have the manual for the module, look at the wiring diagram inside the door of the connection wires on the module.

You could also open the HWConfig editor, go Online, and check out the diagnostics on the modules (they should with a red symbol in the hardware editor Online if the SF LED is active).
Hope this helps,
Daniel Chartier

[dwcy]

Thank you for your quickly rely. I had measured the power supply at the AI module, it was ok. And I cannot find any error event when check out the diagnostics buffer.

[dchartier]

Hello Dennis;

here is a list of problems that will turn the SF LED ON on your Siemens AI module:




Check these conditions on your AI and tell us if any are causing the problem.

Hope this helps,
Daniel Chartier

[Rookie_Eng]

Are you communicating with Rack 1? I have seen in the past if a local or extended rack is not online the analog module will show a SF fault at the module. You can verify this by going online with your hardware configuration. Also, its not a bad idea to go online with your hard config, you may be able to get more insight with what is wrong with the analog module. Once online in the hardware manager right click on the analog module exhibiting the error for more detailed information.

Good Luck.

[sylent]

Hola!
Not sure which analog input card you have, but if you have the one that every 2 channels is configurable for a different measuring type then you will have some little square plastic range thingies on the side that have to be in the right position. I think it is A,B,C, and D positions. So if in your HW config you set up 2 points to be 4-20ma and 2 others for 0-10V and another 2 for J type thermocouple and the last 2 for 4-20ma again then the little plastic squares would need to be arranged D-B-A-D on the side - think the default is for them to all be on B which is a voltage measurement. But of course you need to make sure that you have the 24VDC wired correctly to the card - and you may not have the card that lets you select; so....not sure if this is of any use.

[allscott]

Remember if you have wire break configured and no analogs wired to your card, you will get a sf for a broken wire condition.

[Fox]

Hi,

I agree that you may check the hardware configuration to know if the default configuration is for 4-20mA. If so, the module will give an error because the current is below 4mA.

To have a message in the CPU you must activete (if possible) the diagnostic option in the hardware configuration of each module.

Did you know that for your configuration you could use one VIPA CPU and you won't need the IM modules? With VIPA CPUs you can connect untill 32 modules in a single rack and save a lot of money.
Manuel Raposo