Allen-Bradley Powermonitor 3000 User Manual page 78

4-18 Communications
Publication 1404-UM001D-EN-E - October 2004
Expressing Data in Data Tables
The Powermonitor 3000 may express metering data in several formats
in the communications 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 Powermonitor 3000 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
0 -3
10 , 10 ). Refer to Table A.14 Metering Real and Apparent Energy
Results on page A-22 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
to 999 or 9999 and a typical exponent element ranges from -4 to 21.
Timestamp format. The Powermonitor 3000 expresses timestamps in
an array of four data table elements: Year, Month/Day, Hour/Minute,
Second/ Hundredth of a second
Each timestamp parameter (except the Year) is a combination of its
first and second element. For instance, the Month is the parameter
value divided by 100 and the remainder is the Day. Example: 1230 =
December 30th. The timestamp data type may be integer or
floating-point and depends on the data table.
Other common data table elements
The Powermonitor 3000 uses several common data table elements in a
number of data tables. These include:
• Password: A valid password must be written to change
configuration settings or issue commands. For selecting records
to read back, you may write either a valid password or a value
of -1. Default 0000, range 0000 to 9999.
9 6 3
, 10 , 10 ,