Please read the following items:

PROLINX CONFIGURATION

Since the 1747-SN transfers up to 60 words of data for each block transfer,
it is necessary to configure:

BTR Register Count <=60
BTW Register Count <=60


LADDER LOGIC CONFIGURATION

N7:60 = BTR Control (set by ladder logic) Bit 7 = 1 for BTR
N7:61 = BTR Block Length (<=60)
N7:62 = Rack Number/Group/Slot . 
        For example, to configure the for rack 3, group 0, slot 0 enter 300  

N7:63 = BTR Control (set by ladder logic) Bit 7 = 1 for BTR
N7:64 = BTW Block Length (<=60)
N7:65 = Rack Number/Group/Slot . 
        For example, to configure the for rack 3, group 0, slot 0 enter 300

Obs: The second word on the BTW block (N11:1) contains the BTW length.