Redundant i/o mapping

[Prashant Yelattiwar 0]

Hi all, I am new to Siemens PLC...So need help regarding I/O redundancy... The system is CPU 414-4H with redundant I/Os on IM 153-2, means if the first IM module has one DI module at slot 4 (address 0,1), then the second redundant IM module also has one DI module at slot 4(address 2, 4). the signal coming from field will go to the same channel of both the DI module. Now my problem is : If PLC is getting a Digital input from field at I0.0 and same is wired to I2.0 And if I want to use this signal in PLC programming, do i have to AND/OR both the DI i.e. I0.0 & I2.0? Or simply using I0.0 will solve the problem...? If second IM module is acting as a active module then using DI I0.0 will work? Please help if somebody know about this. Regards & best wishes, Prashant Yelattiwar