I dont know the information below is useful or not. I just thought of sharing it. I refer to the manual 3SB3 Profibus DP Individual Interface User Description. I hope the basic diagnostic indications and settings are standard for Profibus devices atleast Siemens Devices.
You had written SYS OK and DP FAIL is lit in the module. Considering SYS OK and DP FAIL of Genop is equivalant to PROFIBUS DP and ADDRESS FAIL indication of 3SB3 we may conclude as below.
PROFIBUS DP -- ON = Device is exchanging data with Master (Normal Operation)
FLASHING = Device is waiting to exchange data with Master
ADDRESS FAIL -- ON = The addresses of the connected modules have collided.
Two modules on one line are set same address or a module
OFF = A line address has not been assigned twice.
So the problem could be the DP address set on the GENOP is not unique or already set on another device in the network or the GENOP is faulty.
S1 switch is for setting the Profibus DP address of the module. Generally there are eight dip switches for address setting. From left to right the address is assigned and switch eight is not used. The address setting of switches 1 to 7 are 2^0, 2^1, 2^2, 2^3, 2^4, 2^5, 2^6.
Assuming switch 1 and 2 are on then the address is 3 is caluclated as 1 x 2^0 + 1 x 2^1 + 0 x 2^2 + ...0 x 2^6 = 1 + 2 + 0 + ... + 0 = 3.