siemens FM350-2 question

Hi
Once again need your help.Looking for information about module FM350. We observed sometimes the module is counting negative value starting from zero, which is creating problem. After going through the DB assosiated to it , it has been seen that bit 40.5 is true (direction counter down) , But unable to find out what make it true. How can I reach to its origin?

use the cross reference reference data.
You should also check for byte/word/sword references that overlap the bit.

One more question regarding FM350-1. I got used siemens PLC configuration S300 + FM350-1. PLC is working well, but I have problems with FM350. I need to test it if it is ok.
So, when PLC starts it's (FM350) SF led is ON and then it is OFF. So everything is ok with module configuration and in general it's burned. I changed module control to Hardware Gate to be able start and stop counting using I0 and I1. So as for me it should LED when I put signal on I0 and I1, but it doesn't. All LEDs are off. So how can I test the module? Tried load simple example of using FM350, but I didn't get any data from encoder.
Also tried to load wrong configuration to module and it's SF was ON. So module sees configuration and react.
MY configuration is:
Gate signals: Level-Controlled
Signal type: 24V initiator
Operating mode: Continuous
Gate control: HW Gate

P.S. ask details if my english is not clear enough.
Thanks