User Manual, Firmware rev. 3.0 or LATER Owner's manual

82 Publication 1404-UM001F-EN-P - November 2009
Chapter 4 Communication
Let’s look at the Date and Time table as an example.
• CSP file number: N11
• Remote I/O BT length: 12
• CIP assembly instance: 6 (Write) or 7 (Read)
• Data table name: Date and Time
• Data access: Read/write
• Number of elements: 8
• Data type: Integer
• User-configurable: No
The power monitor data tables are listed in Appendix
A. The table on
page 188
shows a summary of all the data tables.
Expressing Data in Data Tables
The power monitor may express metering data in several formats in
the communication data tables.
Floating-point data type is used to express most metering results. The
trend log, min/max log and the user-defined data table also return
values in floating-point format. The power monitor uses the IEEE 754,
32-bit floating-point format that is compatible with Allen-Bradley
PLC-5 and SLC 500 controllers.
Modbus float data type returns IEEE 754 floating point values in a
big-endian two-register array.
Integer data type (16 bit) is used in most configuration data tables and
some results data tables.
Integer array format is used to express real, reactive and apparent
energy results. Each of these values is expressed as an array of five
integer values, each scaled by a different power of ten (10
9
, 10
6
, 10
3
,
10
0
, 10
-3
).
Refer to
Metering Real and Apparent Energy Results Parameters on
page 210 for additional detail.
Integer/exponent format is used for some specific table entries such
as IEEE-519 short-circuit current. The integer element is in the range
of 0…999 or 9999 and a typical exponent element ranges from -4…21.