DENT Instruments powerscout 3037 User Manual

30
SELECTING A SCALAR
The use of Modbus protocols limits the data registers to a maximum of two
bytes (16 bits) or a maximum decimal value of 65535. Modbus requires that
the data be unsigned (positive) integer values. To overcome these
limitations some measured (and stored) values must be scaled to fit into the Modbus registers. The raw
value read from the Modbus registers is multiplied by a scalar to convert the raw data. The following
table lists the data scalars and the respective values for the PowerScout.
Data Scalar
Scalar Value
kW/kWh
Demand
kVAR/kVARh kVA/kVAh
Power
Factor
Amps Volts
0
.00001
.00001
.00001
.01
.01
.1
1
.001
.001
.001
.01
.1
.1
2
.01
.01
.01
.01
.1
.1
3
.1
.1
.1
.01
.1
.1
4
1
1
1
.01
1
1
5
10
10
10
.01
1
1
≥6
100
100
100
.01
1
1
Table II-9: Data Scalars and Values for Registers 44001 thru 44061
The data scalar is stored in register 44602.
When selecting a data scalar, the following guidelines need to be considered:
 If the data scalar selected is too low, an incorrect data result is returned from the register.
 If the data scalar selected is too high, the significant digits following the decimal point are
removed.
After selecting a data scalar, the formula for calculating the actual value is:
register value X scalar value = actual value
Or, another way to state this formula is:
actual value/scalar value = register value
DID YOU KNOW: The
register value must
be less than 65,535.
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DENT Instruments powerscout 3037 Specifications

General

Brand	DENT Instruments
Model	powerscout 3037
Category	Measuring Instruments
Language	English