CCS WattNode WNA-1P-240-FT10, Руководство пользователя

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28 Operation
The WattNode also supports rolling demand (also called “sliding window”), in which the demand intervals
are evenly divided into a fixed number of subintervals. At the end of each subinterval, the average power
over the demand interval is computed and output. This results in better accuracy, especially for demand
peaks which would not have lined up with the demand interval without subintervals. The first measurement
will not be reported until one complete demand interval has elapsed. From 1 to 15 subintervals are
supported, provided that the subinterval duration is at least 30 seconds. A subinterval count of one results
in the standard demand measurement without rolling demand.
Demand
Subinterval
Demand
Subinterval
Demand
Subinterval
Demand
Subinterval
Demand
Subinterval
Demand
Subinterval
Demand
Subinterval
Demand
Interval
Demand
Interval
Demand
Interval
Demand
Interval
Demand
Interval
Power (watts)
Demand
Power
Curve
Figure 4.7: Rolling Demand with Three Subintervals
4.4.1 Demand Configuration
The demand is configured with
nciDemPeriod
to set the interval over which demand is measured, and
nciDemSubints
to set the number of demand subintervals.
nciDemPeriod
variable is a SNVT_elapsed_tm
type variable which contains fields for day, hour, minute, second and millisecond. The demand interval can
never be longer than 12 hours, so the day field should always be zero. The hour field can range from 0 to
12 hours, the minute field from 0 to 59 minutes, and the second field from 0 to 59 seconds. The millisecond
field is not used.
The
nciDemSubints
can be set from 1 to 15. The time period of each subinterval is the demand interval
divided by the number of subintervals. Setting this value to 1 disables subinterval computations.
An example configuration could use a demand period of 1 hour with 6 subintervals. This would result in a
subinterval period of ten minutes. Every ten minutes, the average power over the last hour would be
computed and reported.
If the WattNode is measuring demand for billing or sub-metering, see 3.3.1 Authentication on
information to prevent unauthorized tampering with these configuration variables.