32
Values Requiring Two Registers
Additionally, some values (e.g., kilowatt hours) may cover a dynamic range that is larger than 65535 and
require two Modbus registers. Any parameter in the
Modbus Register Assignment
tables that shows
two registers (identified by the terms MSW (Most Significant Word) and LSW (Least Significant Word))
are examples of this wide-ranging parameter.
To interpret the values contained in these registers, the steps are:
2) Multiply the MSW register by 65536.
3) Add the result to the value found in the corresponding LSW register.
4) Multiply the result by the appropriate scalar value from Table I-2.
For example, assume that System Total True Energy (kWh) is desired and the
value of 5013 is read from register 44001 (LSW) and 13 is read from register
44002 (MSW) and that the register 44602 data scalar is set to 3.
To calculate the total kWh recorded:
Multiply the MSW by 65536: 13 X 65536 = 851968
Add the LSW: 5013 = 856981
Multiply by the scalar 3 value of 0.1: 856981 X 0.1 = 85698.1 kWh
Comms Setup
Use this tab to change communication parameters for the meter, such as communication protocols and
how those communications are transferred. This screen displays the fields pertinent to your power
connection and communication protocol, so if you are connected by RS-485 then only those fields are
shown. However, if you are connected with a USB cable all fields are displayed. Changes to these fields
override any settings on the Communications tab.
D
ID
Y
OU
K
NOW
?
When reading two
register values,
ViewPoint
automatically
calculates the total
value.
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GlobalTestSupply
.com
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