Rockwell Automation 1425 PowerMonitor Wireless 250 User Manual
Page 39
Rockwell Automation Publication 1425-UM001A-EN-P - January 2012
39
Software Interface
Chapter 3
Interval Energy Usage Data (Register 28 …48)
Energy is integrated over a user-selectable recording time interval. Refer to
Recording Interval Time (Register 53)
The interval energy usage values are calculated over the recording interval. At the
end of each recording interval, the values are stored in the interval energy
registers. The recording interval timestamp indicates the time at the end of the
recording interval.
Interval real and reactive energy values are expressed in a signed 16-bit INT
register with a raw value range of -32,768…32,767. Interval apparent energy
values are similarly expressed in an unsigned INT with a raw value range of
0…65,535. The raw value is the value before the scaling factor is applied.
With certain combinations of load and interval time, the interval energy may
exceed the range of the registers. In this case the registers will roll over (like a car
odometer) and report incorrect interval energy. The tables below list calculated
interval energy register raw values at various percentages of nominal phase
current (Ipn) and nominal voltage for the particular power monitor model
(240V or 480V) and 100% power factor. Values in bold font in the tables indicate
where a value rollover is likely to occur.
We recommend that you adjust the interval to a shorter time period to avoid this
issue.
lists real or reactive energy values (one phase/sum of phases) at varying
percent of nominal phase currents with nominal voltage 240V or 480V for SP2
model and 100% power factor (0% power factor for reactive energy).
Table 20 - Real or Reactive Interval Energy Raw Values
Load Current
25% Ipn
50% Ipn
100% Ipn
120% Ipn
Interval Time (min)
5
1600 / 4800
3200 / 9600
6400 / 19200
7680 /23,040
6
1920 / 5760
3840 / 11,520
7680 / 23,040
9216 /27,648
10
3200 / 9600
6400 / 19,200
12,800 / 38,400
15,360 / 46,080
12
3840 / 11,520
7680 / 23,040
15,360 / 46,080 18,432
/
55,296
15
4800 / 14,400
9600 / 28,800
19,200 / 57,600 23,040
/
69,120
20
6400 / 19,200
12,800 / 38,400 25,600
/
76,800 30,720
/
92,160
30
9600 / 28,800
19,200 / 5,7600
38,400 / 115,200
46,080 / 138,240