Rockwell Automation 1771-QRD PULS FLOWMTR - Manual (Page 10)

Introduction
Chapter 2
2–2
Figure 2.1
A Typical Channel
The QRD is operated with block transfers. Block Transfer Reads report the
count values, rates, and both overrange and overflow flags to the PLC.
Block Transfer Writes are used by the PLC to reset the total count or to
reset the overflow flags.
How the 1771-QRD Works