Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 183)

ASCII Module
PLC-2 Family Processors
Appendix A
AĆ15
ST = PS + T(read) + PS + T (write)
= 48 + 10.34 + 48 + 0.42
= 107ms (rounded)
This is the worst case time between two consecutive read block transfers
for the Mini-PLC-2/15 controller as described in example problem 3.
A read (only) program for transferring data from your ASCII device into
the data table of your processor is presented with rung descriptions
(Figure A.6).
Example Read (Only) Program