Siemens S7 analog in, red SF light lit

Hello.

I'm on my way to a plant to debug a problem they have. On one of Siemens analog in modules AI8 x 12 bit, 6ES7 331-7KF01-0AB0, There is the SF light on the top of the card lit.

I know of two scenarios that can cause this light to be lit.
1: The diagnosis for the card as enabled, but there is no sensor connected to the channel which is enabled.

2: The square dip switches, on the side of the card, which dip two channels (there are four of them) are not set according to the hardware configuration.

Do any of you know other things which can activate the SF light? I want to be prepared when I get to site, since they want to limit downtime as much as possible.

Thank you for any feedback.


brg
Andreas

The attaches picture is taken from Siemens Manuel (6ES7398-8FA10-8BA0)

All you need is there. In the PDF it is in 278th page (4-72)

Also after you tried everything mentioned. Check the backplane pins of the module and the backplane connector.

And likely the module could be broken down so you can need a new module...

First thing listed in the manual is the first thing I thought of: no 24vdc power to the module.