36
Specifications
6.3 Accuracy
The WattNode’s minimum accuracy is 0.45% of reading plus 0.05% of full-scale. The WattNode’s
temperature dependence is less than ±0.01% / °C. The total system accuracy is subject to CT accuracy.
The WattNode can measure power from 0.05% to 150% of rated power at reduced accuracy, which
provides extra range for occasional high loads and for alarms. Due to their nonlinearity, however, the CTs
may not produce accurate readings at very low power levels, and may saturate at very high power levels.
6.4 Timekeeping
The WattNode’s internal clock is accurate to 0.02% with a worst case drift of 8 minutes a month. If the
time of day input variable
nviTimeSet
is updated once an hour, then the WattNode will never drift more
than a second from the true time of day.
6.5 Update Rate
The WattNode measures power every 1.678 seconds and energy every 10.066 seconds. The demand is
measured at the end of each demand interval or subinterval (measured to the nearest 0.839 seconds).
6.6 Ratings
6.6.1 Electrical
Power Consumption: 1.5 – 3.0 watts
Operating Voltage Range: 80% to 120% of nominal
6.6.2 Environmental
Temperature: -30°C to +60°C
Humidity: 5 to 90% RH (non-condensing)
6.6.3 Mechanical
Enclosure: High impact, ABS plastic
Flame rating: 94HB
Size: 143mm × 85mm × 32mm (5.63" × 3.34" × 1.25")
Connectors: Euroblock style pluggable terminal blocks
Light gray: 22 to 12 AWG, 600 V
Black: 26 to 16 AWG, 300 V
6.7 Communication
The WattNode may be purchased with the following transceivers:
Transceiver
Bit Rate
Max. Nodes
1
Max. Distance
Max. Stub Length
TPT/XF-78
78 Kbps
64
1400 m
3.0 m
FTT-10
78 Kbps
64
500–2700 m
3.0 m
2
1
Per subnet (see Echelon LonWorks Products Databook for more details)
2
Only applies to bus topology networks.
Table 6.1: WattNode Transceivers
