Netvox R718N3

Compatibility

Compatible with EpiSensor Edge over LoRaWAN.

Register it on your LoRaWAN network server with its DevEUI and keys. Edge, on the Gateway, reads its decoded uplinks from that server.

Edge reads 9 values from it, listed under Interface.

Connect it with

• 
  Gateway ZGW-20
  From €899 ex VAT Configure Gateway

Specifications

It measures current only. There is no voltage input, so it does not report power, power factor or energy; a kWh figure from it rests on an assumed voltage and power factor. What it does give is a battery-powered view of load profiles, phase balance and run hours on distribution boards and plant, reported to Edge over the radio with no data cabling.^1, 2

Power

Battery. Two 3.6 V ER14505 AA lithium cells (2400 mAh each) in parallel. 3.82 years reporting every 60 minutes at SF10, 20 dBm and 25 °C.¹

Current range

100 mA to 50 A per phase¹

Accuracy

< ±1 % from 300 mA to 50 A¹

Resolution

1 mA¹

Current transformers

3 solid-core, 60 A rated primary, 20 mA secondary, 3000:1, 50 to 60 Hz, < 600 V¹

Transformer size

37.5 × 39 × 14 mm, about 900 mm leads¹

Frequency plans

EU868, US915, AU915, KR920, AS923-1, AS923-2, AS923-3, IN865, CN470; one per unit, set in the factory¹

Transmit power

16 dBm (EU868, AS923), 20 dBm (US915, AU915, IN865), 14 dBm (KR920)¹

Receiver sensitivity

-136 dBm at SF12¹

Ingress protection

IP53 main unit, IP30 transformers¹

Main unit

112 × 88.19 × 32 mm, about 141 g; screw or magnet mounting¹

Operating conditions

-20 to 55 °C, < 90 % RH non-condensing¹

Where it is used

• Distribution boards and sub-mains, where three phase currents show load, balance and peaks.

  Transformer and distribution board monitoring

• Plant such as air handling units, pumps and chillers, where current shows when a machine runs and how hard.

  HVAC energy monitoring for commercial buildings

Interface

Device class

Class A²

Regional plans

EU868, US915, AU915, KR920, AS923-1, AS923-2, AS923-3, IN865, CN470

Ports

Decoded fields

Readings and settings, with units and ranges where Netvox publishes them. R readable, R·W readable and writable.²

Every report is 11 bytes: version 01, device type 4A for the R718N3, report type, then eight data bytes. Battery voltage is the lower seven bits of byte 4 in tenths of a volt; bit 7 set means low battery. Currents are unsigned 16-bit big-endian values in mA.²

A 16-bit value tops out at 65,535 mA, so each current comes with a multiplier. In report types 01 and 02 the multipliers are sent as numbers; in report type 03 they are packed two bits each into the last byte and stand for 1, 5, 10 or 100. Multiply the current by its multiplier before using it.²

Setup

1. Fit the batteries

   Fit two 3.6 V ER14505 AA lithium cells; they run in parallel.¹

2. Register it on the network server

   Add the R718N3 to the site’s LoRaWAN network server as a Class A device on the frequency plan printed for that unit, and load a decoder for ports 6 and 7.²

3. Fit the transformers

   With the circuit isolated, pass one phase conductor through each transformer, never a whole cable, and fix the main unit to the panel with its magnet or screws. Keep it out of closed metal enclosures, which block the radio.

4. Set the reporting

   Send command 01 on port 7 with the minimum and maximum report times and the current change that should trigger a report; the device answers 81 00 on success.²

5. Check one value

   Compare each decoded phase current, after its multiplier, with a clamp meter reading on the same conductor before you enable exports from Edge.

Common questions

Does the R718N3 measure power or energy?

No. It measures AC current through its transformers and has no voltage input, so it reports current only. Power and energy would need an assumed voltage and power factor.^1, 2

Why does a current read low on a large load?

The current field is 16 bits, so it stops at 65,535 mA. Above that the device sends a multiplier with each current, and the reported value has to be multiplied by it. A decoder that ignores the multiplier reads large currents far too low.²

Which LoRaWAN ports does it use?

Readings and alarms arrive on port 6. Reporting settings are sent on port 7, and the device replies on port 7.²

How long do the batteries last?

Netvox quotes 3.82 years on two ER14505 cells reporting once an hour at SF10 and 20 dBm, at 25 °C. Faster reporting or a higher spreading factor shortens it.¹

What size of conductor do the transformers take?

The R718N3’s solid-core transformers are 37.5 × 39 × 14 mm and rated 60 A primary. For larger loads Netvox sells clamp-on versions of the meter from 75 A to 630 A.^1, 3