Rockwell Automation 1794-IP4 Series B FLEX I/O PULSE COUNTER User Manual - Manual (Page 14)

1–4 Overview of the Pulse Counter Module
Publication 1794ĆUM016B-EN-P - August 2002
You can use the 1794–IP4 module in the power management,
automotive, food and beverage, and oil and gas industries for various
flow and/or turbine metering applications. Some sample
applications include:
•
quantity counting
•
speed calulations
•
brewery flow monitoring
•
petrochemical flow and custody transfer
The Pulse Counter module has 4 identical input interfaces. Each of
the input channels may accept + and – input signals:
•
N+ and N–
•
D+ and D–
The pulse inputs can accept frequencies up to 100KHz. The module
accepts and returns binary data.
Each of the 4 counters has two 16–bit counter registers.
Variables
Communication between the Pulse Counter module and the control
system take place using variables accessible in the control system
program. Examples of variables are:
•
selection of clock frequency (ClockFrequency)
•
selection of measurement type (SelectMeasureType).
Control words are used to set parameters for configuration. Control
words sent to the Pulse Counter module are read back to the control
system to verify that at least 1 I/O scan has been performed since the
control system cycle which initiated the frequency module
command.
Select Type of Measurement
The module can be configured for 2 alternate functions using the
variable SelectMeasureType. Each of the 4 inputs can be individually
configured.
SelectMeasureType Function
0 Period time measurement using a 16-bit counter register and the
function of a 16-bit accumulating counter
1 Period time measurement using a 32-bit counter register
Typical Applications
Input Capabilities