Allen-Bradley POINT I/O 1734-VHSC24, User Manual, Page: 9 / 64

1 Publication 1734-UM003A-EN-P - August 2000
Chapter
1
About the Very High Speed Counter Modules
General
In this chapter, you will learn about the types of very high speed
counters, their features and capabilities.
Introducing the Very High
Speed Counter Modules Module Overview
The counter modules install into the Point I/O terminal base (1734-TB
or -TBS) and interface with the Point I/O DeviceNet Pass-through
(1734-PDN) or the Point I/O DeviceNet Adapter (1734-ADN). The
Counter Module serves as a "signal conditioner" and "function block"
(i.e. a counter) between the customer process signals on the terminal
base and the PointBus containing the command information. The
three main functional blocks are the customer digital I/O interface, the
counter "ASIC" and the microprocessor.
Functional Overview
The Counter Module accepts feedback from:
– encoders (either single ended or differential)
– pulse generators
– mechanical limit switches
– frequencies up to 1MHz
A filter is available with four settings:
•
50Hz
•
500Hz
•
5kHz
•
50kHz
The filter can be turned off to achieve the fastest counting rate.
The input voltage range is 5Vdc (VHSC5) or 15-24Vdc (VHSC24). The
module returns the count or frequency in the form of a 24 bit binary
number (0 - 16,777,215) expressed in a 32 bit long word. Each
counter has a user selectable preset and rollover value associated with
it.