Rockwell Automation 1771-DA,D17716.5.13 U MNL 1771-DA ASCII I/O MODULE - Manual (Page 159)

Function of Control/Status Bits
Chapter 6
6Ć24
Status Word Two
Bit Function Status*
17Ć10 Number of strings per
Block Transfer (when
transferring multiple
strings., IW2(17) = 1)
Bits 10Ć13 = BCD digit 0
Bits 14Ć17 = BCD digit 1
07Ć00 Number of Words per
String
Bits 00Ć03 = BCD digit 0
Bits 04Ć07 = BCD digit 1
*The module sets these bits (unless toggled) when it detects the subject condition.