If modules (I/O cards) are not appearing or functioning properly in the S-4000S, it is most likely due to improper module installation. Be sure that the following rules are adhered to when installing modules:
https://static.roland.com/assets/media/pdf/S-4000S_l_Module_Installation_e01_W.pdf
Note that the same rules apply when using SI-DA4 digital input and SO-DA4 digital output modules.