Rockwell Automation 1771-QRD PULS FLOWMTR - Manual (Page 9)

Chapter 2
2–1
Introduction
In this chapter you will read about:
1771–QRD Pulse Flowmeter Module features
How the 1771–QRD Module communicates with programmable
controllers
The Catalog No. 1771–QRD Pulse Flowmeter Module is an intelligent
block transfer module that interfaces Programmable Controllers with
magnetic pickups, single channel shaft encoders, and turbine flowmeters,
or with any source of TTL pulses. The module is generally compatible
with, but does not require the use of, turbine flowmeter signal
preconditioning modules. It provides rate and count data in 2’s
complement binary format to the processor data table through block data
transfers.
Rates as high as 10.0 kHz and counts as large as 32,767 are supported. At
overflow, the count continues from zero and an overflow flag is set. The
overflow flag can be reset by the ladder logic. In addition, the PLC can
reset any or all counts directly.
The module functions with reduced performance in PLC–2 systems due to
their three digit BCD operation. Rates as high as 0.999 kHz are permitted
as are total counts of any size, provided that the PLC ladder polls the
module at intervals faster than it can acquire 999 counts.
The 1771–QRD module receives +5 Vdc operating voltage through the I/O
chassis backplane. It draws a maximum of 0.50 A from this supply.
The module is implemented in a 1771 single-density module form factor.
Chapter Objectives
Module Description and
General Features