Rockwell Automation 1746-HSCE2 Multi-Channel High Speed Counter Module - Manual (Page 53)

Publication 1746-UM002B-EN-P - August 2004
Configuration and Programming 4-3
Data Format
In Class 4, the counter accepts rate data in either integer or
floating-point data formats, depending upon the setting of the rate
value bit. Both formats are explained below.
Integer Format
In integer format, two words may be needed to hold each data value
because the values can exceed ±32768 (decimal) when the module is
in Class 4 operation. The combined decimal value of both words is
calculated as follows:
actual value = (value of first word x 1000) + value of second word
Both word values must have the same sign or a programming error
results. If the value is positive, both words must be positive. If the
value is negative, both words must be negative.
The following example illustrates how numbers are represented in
integer format.
Floating-Point Format
Floating-point notation (IEEE 754 single-precision used) is difficult to
read and use, but may be simplified by using programming software
to view and use the data in a floating-point file.
TIP
Count values are always in integer format. The
format of rate values is selected in the Module Setup
Block as either integer or floating-point formats. All
other data is in integer format.
TIP
A value of zero in either word may be paired with
either sign in the other word.
Table 4.1 Integer Format Example
First Word Second Word Data
12 345 12,345
-12 -345 -12,345
12 0 12,000
-12 0 -12,000