S7-300 Input signal error

Am using CPU 317-2 PN/DP V3.1(6ES7 317-2EK14-0AB0), but in the software it is V2.6 (6ES7 317-2Ek13-0AB0) earlier it was showing the system fault & now its not.

The actual problem is am having 9 ET200S stations connected on PROFIBUS to the CPU and few of the input module status are not getting updated in the PLC CPU. Always it shows the input status is HIGH (=24V) at the terminal even though I removed the connections of the terminal.

The ET200S details are, IM151-1 Standard 6ES7 151-1AA05-0AB0 and 4DI modules 6ES7-131-4BD01-0AA0.

Transmission rate - 1.5MBPS

Slaves - 9x ET200S IM151-1 standard

6x DP/DP couplers

3x repeaters

31x Danfoss drives

Suggest me to solve the input status problem..................

Thanks