Rockwell Automation 1408-EMxx PowerMonitor 1000 Unit - Manual (Page 14)

14 Publication 1408-UM001B-EN-P - May 2008
Chapter 2 Powermonitor 1000 Memory Organization
The power monitor requires a valid password before it accepts a
write. There are two ways a password may be written.
•
An entire table including a valid password may be written.
•
A valid password may be written to the Single element password
write table which then enables single element writes until
30 minutes without a single element write elapses.
Data Table Data Format The power monitor stores data in two basic formats.
•
Integer, in which the 16-bit word may be represented by a
signed integer value or a bit field
•
Floating-point, in the 32-bit IEEE 754 format
Modbus input registers and holding registers are 16 bits long. Floating
point values in the data tables are represented as big-Endian
two-register arrays in IEEE-754 floating point format. The Modbus
client application must be able to reassemble the two-word array into
a valid floating-point value.
An example Modbus address for a floating-point value is 40101-2.
Register 40101 holds the most significant bytes of the number and
40102 holds the lowest significant bytes.