The s 88 contact must be assigned here so that it can be recognized at a glance. 

Please note that the contacts 1 through 16 are only available on the first s 88 module. The second s 88 module has contacts 17 through 32. 

The right contact can be found easily with the formula M - 1 x 16 + N 
M = number for the feedback module
N = number for the connection in question