Exhibit C. VoltDrop Installation_User Manual.pdf

VoltDrop™Multi-Phase Energy Meter Installation and User Guide

Version A.03 - Beta May 29, 2025

VoltDrop Installation and User Guide Version A.03 - Beta

Contents

Important Safety Instructions 3

1 Introduction 5

1.1 VoltDrop Meter

1.2 VoltSafe Harness

1.3 Alternative Input Cables

2 Specifications 8

2.1 Metering Characteristics

2.2 Operational Characteristics

2.3 Mechanical Characteristics

2.4 Communications

2.5 Certifications

2.6 Warranty

3 Use-Case Scoping 10

3.1 Applicable Circuit Types

3.2 Input Cables and Sensors

3.3 Install Location

4 Installation 12

4.1 Unpacking and Preparation

4.2 Grounding

4.2.1 Device-Side

4.2.2 Panel-Side

4.3 Phase Identification

4.4 VoltSafe Harness Installation

4.5 Split-Cable Installation

4.5.1 Rogowski Coil Installation

4.5.2 Current Transformer Installation

4.5.3 Voltage Tap Installation

4.5.4 Bare-Wire Installation

4.6 Connecting the VoltDrop

4.6.1 Continuity Testing

4.6.2 Phase Connections and Power-On

4.7 Mounting

4.8 LoRaWAN Connectivity

www.vutility.com 1

5 LoRaWAN Data Format 21

5.1 Introduction

5.1.1 Data Length Restrictions

5.1.2 VoltDrop Open-Source Codec

5.1.3 VoltDrop LoRaWAN Port Field

5.2 Uplink Packet Definitions

5.2.1 Packet 38 - Comprehensive

5.2.2 Packet 39 - Voltage and Phase Angle

5.2.3 Packet 40 - Voltage and IEC Power Factor

5.2.4 Packet 41 - Amperage and Peak Amps

5.2.5 Packets 42/43 - Active (Real) Energy

5.2.6 Packets 44/45 - Apparent Energy

5.2.7 Packet 46 - Startup Diagnostic

5.2.8 Packet 47 - Operational Diagnostic

5.3 Downlink Configuration Definitions

5.3.1 Device Reboot (Soft Reset)

5.3.2 Factory Reset

5.3.3 Transmit Interval

5.3.4 Data Schedule

5.3.5 Channel Options

6 Troubleshooting 48

6.1 Radio Status Flashing Codes

6.2 VoltDrop Status Color Codes

6.3 Common Issues and Resolutions

7 Appendix - Voltage Tap Specifications 54

7.1 Mechanical Characteristics

7.2 Wire Gauge and Outer Diameter

8 Appendix - Wiring Color Codes 56

8.1 US / Canada - NEC

8.2 Europe - IEC and legacy UK

8.3 Australia and New Zealand

8.4 Japan

9 Appendix - Glossary of Terms 59

10 Revision History 61 www.vutility.com 2

IMPORTANT SAFETY INSTRUCTIONS

This manual and device labels provide important safety warnings. Do not use the device in an unspecified manner. Misuse of the device may impair the user’s protection.

DANGER

Indicates a hazardous situation which may cause serious injury or death.

WARNING

Indicates a hazardous situation which may cause injury, damage to the device, or improper operation.

DANGER

• This device should only be installed and serviced by a licensed electrician.

• Use appropriate personal protective equipment (PPE) rated for the electrical source.

• Risk of fire or explosion: Device is not rated for use in explosive or flammable atmospheres.

• Risk of electric shock: Device is not rated for use in wet or condensing humidity environments.

• Risk of electric shock: High voltage, do not open or disassemble. The device contains no user serviceable components.

• Risk of electric shock: Use only approved accessories and cable harnesses.

• Risk of electric shock: Phase cable harnesses must be disconnected from device before servicing ground (GND) connection.

www.vutility.com 3

WARNING

• Ensure that the ground lug screw is present in the terminal block before attempting installation.

• Follow installation procedures, ensure that the system is grounded before connecting phase input cable harnesses.

• VoltDrop requires a low-impedance neutral to ground bond. Systemswith significant neutral to ground offset will produce erroneous results and may damage the device.

• Do not exceed maximum voltage ratings. The device is not designed for delta-type circuits, including those with a neutral line.

• Do not exceed device temperature ratings.

• The device contains magnets. Exercise caution around pacemakers and other medical devices.

• Do not drill screw mounting points in a live electrical panel.

• Do not insert foreign objects or use excessive force on connectors.

WARNING

National Electrical Code (NEC) requires a Disconnecting Means/Overcurrent Protection to be installed on all electrical systems. It is the customer’s responsibility to meet applicable electrical regulations. VoltDrop is intended to be installed downstream from Disconnecting Means/Overcurrent Protection on monitored circuits.

www.vutility.com 4

1 Introduction

This document provides operating, maintenance, and installation instructions for the VoltDrop multi-phase energy meter.

VoltDrop is a wireless and self-powered energy monitoring device. It is capable of reporting various metrics such as apparent and active energy, voltage, amperage, phase angle and power factor. Values are averaged or accumulated from high-frequency readings and reported via periodic wireless transmissions.

The meter is suitable for a variety of common electrical systems ranging from residential single-phase to industrial/commercial three-phase Wye. See the Use-Case Scoping section for applicable circuit types and voltages.

A variety of input cables provide options for flexible Rogowski coil and high-accuracy current transformers. Note that the VoltDrop must be factory calibrated to the sensor type shipped with the device and use of the incorrect input cables will result in erroneous readings.

VoltDrop uses sub-gigahertz LoRaWAN for long-range wireless communication. This Internet of Things (IoT) interface can be deployed as a private network, or used with a public one. The use of short data messages increases transmission reliability in suboptimal environments such as metal electrical panels.

WARNING

VoltDrop is intended for indoor applications only and must be installed in an electrical panel conforming to applicable electrical codes for the monitored circuit.

www.vutility.com 5

1.1 VoltDrop Meter

Metering Module

Ground Wire

Drillable Tab for Screw Mounting

Communications

Module

Factory Configuration

Port (No user access)

LoRaWAN Radio

Antenna Port

Communications

Status LED Light Meter Status

LED Light

Phase Inputs

Ground Terminal

Access Hole

1.2 VoltSafe Harness

The VoltSafe Harness is a custom 24" circumference Rogowski coil with an integrated voltage tap. The integrated tap in the harness head allows penetrating the conductor insulation for access to the phase voltage and affixing the current sensor in a single unit. The unit is fixed in place with nylon cable straps (i.e. zip-ties) passing through channels in the Rogowski coil head.

Zip-Tie

Channels

Insulation

Piercing Tooth

Conductor Centering

Channel

Rogowski Coil

Twist-Lock

Rogowski Coil

VoltSafe Harness

Integrated

Voltage Tap

(Length Not to Scale) www.vutility.com 6

When installed per the instructions in this manual, the design of the Rogowski head inhibits user access to the insulation piercing tooth. This enables the VoltSafe harness to be integrated into live electrical systems without the downtime typically associated with electrical work.

1.3 Alternative Input Cables

The VoltDrop now offers a selection of input cables that enable mounting the voltage input and current sensor separately. These cables split partway through their length and feature electrical current sensors without an integrated voltage tap. The separate voltage input can be factory terminated with a voltage tap similar in design to the VoltSafe harness, or provided as a bare wire for user termination.

The split cables are available in a range of Rogowski coil sizes, or with a high-accuracy current transformer. See section 3: Use-Case Scoping for available input configurations.

Zip-Tie

Mount

Conductor Voltage Tap (See VoltSafe Harness)

Voltage Input Avaliable as Bare-Wire

(Lengths Not to Scale)

Rogowski Coil

Twist-Lock

Multiple Rogowski Coil Sizes Avaliable

Current Transformer Input for High Accuracy and Low Current Systems

Cable Splits for Separate Voltage and Current Paths www.vutility.com 7

2 Specifications

2.1 Metering Characteristics

Accuracy IEC Class 2 Meter (±2%) Sampling Rate / Bandwidth 8kHz / 2 kHz Data Aggregation Mean/Averaged Reporting Interval 1 Minute (minimum, value configurable)

2.2 Operational Characteristics

Min Typical Max Unit

Line-to-Neutral Voltage 85 – 305* VAC Frequency 47 – 63 Hz Operating Current (277 VAC) – 0.015 0.12 A Temperature Range 2 – 80 °C Humidity – < 60 80 %RH

[*] 3-Phase Wye circuits indicate Line-to-Line voltage. The Line-to-Neutral voltages of these systems are significantly lower. E.g. 480VAC Wye (Line-to-Line) is 277VAC Line-to-Neutral

Overvoltage Category CAT III 300VAC Pollution Degree 2 Operational Altitude 2000m

2.3 Mechanical Characteristics

Weight 3.7 oz (105g) Ingress Protection IP51 (indoor/sheltered only) Dimensions 1.25"W × 1.25"D × 14.5"L (3.18cm × 3.18cm × 36.83cm) Mounting Magnets on back of device, self-tapping screw (not-included) Voltage Tap See section 7: Appendix - Voltage Tap Specifications www.vutility.com 8

2.4 Communications

Wireless Interface 800-900MHz LoRaWAN LoRaWAN Specification 1.0.2 RevB LoRaWAN Device Class Class A Transmit Power +20dBm Receive Sensitivity -137dBm

2.5 Certifications

Model No. PPE-2500 ETL UL 61010-2-030, CAN/CSA C22.2 No. 61010-1-12 & 61010-2-030

FCC ID 2APCG-VUHDC1

RoHS Compliant

2.6 Warranty

One year from date of purchase. Extended warranty negotiable by contract.

Calibration and repair to be performed by manufacturer only. The VoltDrop contains no user serviceable parts, disassembly of case voids warranty.

www.vutility.com 9

3 Use-Case Scoping

3.1 Applicable Circuit Types

Minimum Voltage1, 2 Maximum Voltage1, 2

Single-phase two-wire with neutral 100V 240V Single-phase (split-phase) three-wire 110/220V 240/480V Three-phase four-wire (Wye) 120/208V 277/480V

[1] Voltages shown as two values separated by "/" represent the phase-to-neutral (or line-to-neutral) voltage followed by the phase-to-phase (or line-to-line) voltage.

[2] Voltages listed are common mains supply services, other values are suitable provided the line-to-neutral voltage does not exceed the VoltDrop’s maximum limit.

WARNING

• VoltDrop requires a low-impedance neutral to ground bond. Systemswith significant neutral to ground offset will produce erroneous results and may damage the device.

• VoltDrop is not suitable for delta-type circuits. This includes split delta "high leg" circuits with a neutral line.

3.2 Input Cables and Sensors

Sensor Type Window Diameter

Current Range3 Voltage Input

VoltSafe Harness Rogowski Coil 6.9" (175mm) 25–2500A Integrated Voltage Tap

8" Rogowski Rogowski Coil 2.3" (60mm) 20–2000A Bare Wire or Voltage Tap

36" Rogowski Rogowski Coil 11.8" (300mm) 40–4000A Bare Wire or Voltage Tap

NCC300 Current Transformer

0.6" (16mm) 3–300A Bare Wire or Voltage Tap

[3] Currents below 1% of the sensor rating are not guaranteed to meet full accuracy specifications. This is typical and permitted by metering standards.

www.vutility.com 10

3.3 Install Location

• Typical bend radius of the VoltDrop input cables is 2.25" (60mm) with connector and strain relief.

– Approximately 3.5" (90mm) of available panel depth is required to install with cables facing forward.

– Reduced depth installs are possible with cables facing upwards or downwards given sufficient vertical space.

• The VoltDrop can be affixed via the integrated mag-nets on the enclosure or by placing a self-tapping screw though the mounting tab.

Self-tapping screw through mounting tab.

Bottom-facing magnets on enclosure.

DANGER

• This device should only be installed and serviced by a licensed electrician.

• Always follow applicable safety regulations for the electrical voltages present.

• Use appropriate personal protective equipment (PPE) rated for the electrical source.

• Voltage tap cables must be attached inside of a rated electrical panel. Piercing or compromising the insulation of a conductor outside of a panel is a violation of most electrical codes.

www.vutility.com 11

4 Installation

4.1 Unpacking and Preparation

The VoltDrop package should contain the following:

• VoltDrop metering device

• SMA LoRaWAN antenna

• 14AWG Ground cable with ferrule

• Calibration record

• 1–3 input cables, depending on the number of phases ordered

• Cable-straps/zip-ties for mounting

– 2 for each voltage-tap type input (including VoltSafe Harness)

– 1 for each Non-VoltSafe Rogowski coil

Recommended Tools:

• Phillips #2 Screwdriver

• Side cut pliers

• Self-tapping metal screw (if using screw mounting)

• Impact drill (if using screw mounting)

• Non-metallic tensioner for cable straps (zip-ties)

4.2 Grounding

4.2.1 Device-Side

The green 14AWG grounding wire should be connected to the VoltDrop on delivery. Verify that the cable is securely fastened into the terminal before installation.

If the wire is not pre-attached, insert the ferrule into the VoltDrop ground terminal. Tighten the terminal screw through the top access hole, following the clockwise direction indicator.

www.vutility.com 12

If the provided wire is unsuitable for installation, ensure that the wire used is at least 14AWG, is solid core, or has a ferrule (solid sleeve) crimped onto stranded wire. Do not use solder to tin stranded wire in lieu of a ferrule. Failure to use suitable wire or termination may result in a non-robust connection that fails over time.

Ground Wire

Insert until ferrule sleeve is reached.

Turn clockwise (indicated) to tighten terminal.

Ferrule

DANGER

A low-resistance ground connection must be established before the phase inputs can be safely connected to the VoltDrop. In the event the ground connection is disconnected or high-resistance, the ground terminal can become energized.

4.2.2 Panel-Side

Locate the grounding bar strip in the electrical panel or raceway. Attach the ground wire from the VoltDrop to any ground lug. Installers may use any grounding point which has a low-resistance bond to neutral.

4.3 Phase Identification

Locate where the insulated incoming feeder cables in the electrical panel are grouped by phases (L1, L2, L3). Note that there may be more than one feeder cable for each phase. For accurate monitoring, all incoming feeders for a phase must be enclosed by the appropriate current sensor.

The Appendix - Wiring Color Codes in this manual lists common wire coloring conventions.

Current sensors should be installed around each phase group in the raceway as far away from exposed high-voltage busbars as possible.

www.vutility.com 13

WARNING

• It is strongly recommended that the installer manually verify and determine conductor topology. The presence of properly colored conductors does not positively indicate that the system is wired per convention.

• Arc-flash restricted zones are typically less than 36" (92cm) from exposed energized areas, but may differ depending on the system and environment. Follow labeled arc-flash restrictions if present.

• Voltage tap cables must be attached inside of a rated electrical panel. Piercing or compromising the insulation of a conductor outside of a panel is a violation of most electrical codes.

• Install all phase input cables to feeders before attaching them to the VoltDrop meter.

4.4 VoltSafe Harness Installation

This section only applies to installs using the VoltSafe Harness Rogowski coil with an integrated voltage tap.

1. Install nylon cable straps (zip-ties) into the two channels on the VoltSafe Harness head. These will be used to affix the Rogowski and voltage tap onto the conductor. Pre-installing the ties allows for initial tightening with a single hand.

2. Unlock the Rogowski coil loop from the main head by rotating the locking ring counter-clockwise.

3. Starting with the first phase, rotate the cable and align the arrow on the Rogowski coil head so it points in the direction of current flow in the feeders.

4. Loop the Rogowski coil around all the phase feeders and align the integrated voltage tap with one of the conductors.

5. Loosely tighten the cable straps (zip-ties) around the aligned conductor.

Zip-Tie

Channels

Lock

Unlock www.vutility.com 14

6. Close the Rogowski coil loop by inserting it into the har-ness head and twisting the locking ring clockwise. A click should be heard as the lock snaps closed.

7. Repeat steps 1-6 for the remaining phases.

8. Grasping the harness head in the palm of the hand, align the insulation piercing tooth perpendicular to the conduc-tor and press it into the insulation.

9. While holding the harness head in place, tighten the cable straps until the conductor is set into the notch. This will drive the insulation piercing tooth further into the conduc-tor and ensure a robust connection.

10. Ensure that the harness head is tight to the conductor and cannot move due to vibration.

11. Repeat steps 8-10 for the remaining phases.

12. Trim the excess length from the cable straps after instal-lation.

C o n d u c to r

Zip-Ties

4.5 Split-Cable Installation

This section only applies to installs using Alternative Input Cables with a discrete voltage tap or bare wire input.

4.5.1 Rogowski Coil Installation

1. Install a nylon cable strap (zip-tie) through the mounting hole on the Rogowski coil head. This will be used to affix the Rogowski coil to the conductor.

2. Unlock the Rogowski coil loop from the head by rotating the locking ring counter-clockwise.

3. Starting with the first phase, rotate the cable and align the arrow on the Rogowski coil head so it points in the direction of current flow in the feeders.

4. Loop the Rogowski coil around all the phase feeders and align the mounting loop with one of the conductors.

Lock

Unlock www.vutility.com 15

5. Tighten the cable strap around the aligned conductor.

6. Close the Rogowski coil loop by inserting it into the har-ness head and twisting the locking ring clockwise. A click should be heard as the lock snaps closed.

7. Repeat steps 1-6 for the remaining phases.

Zip-Tie

4.5.2 Current Transformer Installation

1. Open the current transformer by gently prying the release latch forward. Only a few millimeters of forward pull is required to release.

2. Starting with the first phase, rotate the cable and align the arrow on the current transformer so it points in the direction of current flow in the feeders.

3. Place the conductor in the window of the current trans-former and rotate it closed until a click is heard as the latch engages.

C o n d u c to r

4.5.3 Voltage Tap Installation

1. Install nylon cable straps (zip-ties) into the two channels on the tap head. These will be used to affix the voltage tap onto the conductor. Pre-installing the ties allows for initial tightening with a single hand.

2. Loosely tighten the cable straps around a conductor from the phase monitored by the paired current sensor.

3. Grasping the voltage tap in the palm of the hand, align the insulation piercing tooth perpendicular to the conductor and press it into the insulation.

4. While holding the voltage tap in place, tighten the cable straps until the conductor is set into the notch. This will drive the insulation piercing tooth further into the conduc-tor and ensure a robust connection.

Zip-Tie

Channels

C o n d u c to r www.vutility.com 16

5. Ensure that the voltage tap is tight to the conductor and cannot move due to vibration.

6. Repeat steps 1-5 for the remaining phases.

7. Trim the excess length from the cable straps after instal-lation. Zip-Ties

4.5.4 Bare-Wire Installation

The voltage input on the split-cable can be provided as an 18AWG bare-wire end for customer termination. This may be crimped, soldered, or used with a a third-party voltage tap as desired.

Note that the input wire must have a low-resistance connection to the phase voltage. Resistive connections may impede operation of the VoltDrop or produce erroneous readings.

DANGER

The bare-wire input can only be installed on de-energized systems. This wire has an inline fuse for protection. Removing the fuse will compromise the safety of the VoltDrop.

4.6 Connecting the VoltDrop

4.6.1 Continuity Testing

The VoltDrop is powered from the phase/line 1 input, and this can be used to test continuity between the phase input cables and the feeder conductors. It is strongly recommended that systems using voltage tap type input cables follow this procedure to catch installation issues before proceeding.

WARNING

• Verify that the VoltDrop ground is connected and has a low-resistance bond to the circuit neutral. The VoltDrop will not operate without the ground connection.

• The phase L1 input must be connected before the others. Failure to do so may cause damage to the VoltDrop.

www.vutility.com 17

Phase Input

Cable

Gently insert until lock latches. Press tab to release for removal.

Phase L1 Input Port

VoltDrop Status

Light

1. Select an input cable and gently plug the three-pin Molex MicroFit™connector into the VoltDrop’s first phase "L1" input.

• The locking tab should be on top and will click when seated properly.

• Press the locking tab to release the cable for removal.

• The connectors are keyed and will only accept the cable in the correct orientation.

2. If the status light illuminates, there is conductivity between the conductor and voltage tap.

Disconnect the input and test the next phase cable in the L1 input.

3. Once all phases have been connected in turn to the L1 input, and the VoltDrop has been confirmed to operate correctly each time, installation may continue.

4.6.2 Phase Connections and Power-On

1. Beginning with the first phase "L1" and for each applicable phase, plug the three-pin Molex MicroFit™connector into the VoltDrop’s corresponding input. (See section 4.6.1: Continuity Testing for details)

2. The VoltDrop uses color codes on the status LED to indicate missing or improperly con-nected inputs.

• On a three-phase system, the VoltDrop status light should turn solid green after the blue startup period.

• Alternating green and magenta patterns indicate a missing phase or improper phase sequence for a three-phase system.

• Depending on the system type, a warning code may not necessarily indicate an issue.

(i.e. a split single-phase system does not use the L3 input) www.vutility.com 18

• See section 6.2: VoltDrop Status Color Codes for details on what a specific pattern indicates.

3. Screw the SMA antenna onto the LoRaWAN radio port with a clockwise rotation.

4. Adjacent to the LoRaWAN radio port there is a red status light specific to the radio module.

This should be periodically blinking to indicate that the radio is receiving power from the VoltDrop meter.

4.7 Mounting

The VoltDrop enclosure contains Neodymium magnets on it’s bottom face with two rubber feet.

These allow the device to be magnetically mounted to a sidewall, door, or other metal surface without sliding due to vibration.

If a more permanent mounting is desired, or if the environment is unsuitable for magnetic attachment, a self-tapping screw can be used with the provided mounting tap.

See section 3.3: Install Location for additional details and a mounting diagram. Note that for maximumwireless reception the LoRaWAN antenna should be angled away frommetal sidewalls as much as possible while not being perpendicular1 to the antennas on the LoRaWAN gateway.

4.8 LoRaWAN Connectivity

Once the VoltDrop is powered, note the red status light on the radio communications module.

(See 6.1: Radio Status Flashing Codes)

• On device power-up the radio status light will flash 20 times at 1Hz.

• The status light may then flash once every 10 seconds while the radio’s backup power capacitor charges.

• After a few minutes, the radio status should be flashing either twice or three times every 5 seconds.

– Two flashes indicate that the radio has joined a LoRaWAN network and is operating correctly. The startup diagnostic packet should be received by the LoRaWAN Network Server (LNS) within 30 seconds of the device joining the network.

– Three flashes indicate that the radio is sending join requests in an attempt to discover and connect to LoRaWAN.

1Omnidirectional stick antennas, like those used on the VoltDrop, have weaker signal strength directly above and below the antenna — along the tip and base. Mounting two antennas at right angles to each other can lead to poor alignment and reduced signal strength.

www.vutility.com 19

• The process of joining a device to a LoRaWAN Network Server (LNS) varies depending on the software package used.

– For customers using Vutility.io please see the onboarding documentation at:

https://vutility.com/support/documentation

– Contact the vendor for assistance with other LNS providers.

www.vutility.com 20 https://vutility.com/support/documentation

5 LoRaWAN Data Format

5.1 Introduction

LoRaWAN (Long Range Wide Area Network) is a low-power, wide-area networking protocol designed for wireless communication between devices and centralized gateways. It operates on unlicensed radio frequencies (typically in the 868 MHz or 915 MHz ISM bands, depending on region) and is optimized for long-range, low-bandwidth applications such as remote sensing, monitoring, and control.

LoRaWAN is built on top of LoRa® modulation, which enables robust and energy-efficient data transmission over long range, or under challenging radio environments such as electrical panels.

The protocol defines secure communication, adaptive data rate (ADR), and network scalability, supporting a high device count per gateway.

LoRaWAN networks are typically structured such that devices communicate directly with one or more gateways. These gateways forward data to a LoRaWAN network server (LNS), which handles message deduplication, device authentication, and routing to customer applications.

5.1.1 Data Length Restrictions

LoRaWANadaptive data rate (ADR) and variablemodulation spreading enables tradeoffs between range/noise immunity and data throughput. Devices with good signal strength to the gateway will use efficient data rates and spreading factors to reduce the amount of airtime required to send data. Devices with poor signal will use settings that improve reception at the cost of longer airtime and lower throughput.

LoRaWAN regional specifications limit maximum airtime for devices. This ensures fair access for all systems in highly contested radio frequencies. Because the VoltDrop reports data at a high rate compared to typical LoRaWAN devices, it is required that the data packets have limited size to keep the airtime under the regulatory limits in worst-case conditions.

Note that public LoRaWAN networks may throttle devices that violate their terms of use and often impose additional restrictions on airtime and uplink count.

www.vutility.com 21

5.1.2 VoltDrop Open-Source Codec

Verified open-source JavaScript codecs (data decoders) are available for a variety of major LoRaWAN network servers (LNS). When deploying the VoltDrop it is highly recommended that these be utilized over developing custom implementations when possible.

The codec’s are freely available on GitHub:

https://github.com/the-real-vutility/payload-codecs

5.1.3 VoltDrop LoRaWAN Port Field

LoRaWAN frames contain a "FPort" field which accompanies data payloads. An FPort value of 0, which is reserved by specification, indicates that the payload contains a LoRaWAN protocol control command. FPort values 1 to 223 are application specific and may be defined by users.

VoltDrop sends and receives user-facing data on FPort 3. Data received on other ports will be discarded.

5.2 Uplink Packet Definitions

Uplinks are data packets sent from devices to the LoRaWAN network server (LNS). These definitions contain metering and diagnostic data from the VoltDrop.

The schedule that determines transmit intervals and what data is sent can be customized. See sections 5.3.4: Data Schedule and 5.3.3: Transmit Interval for details on building these LoRaWAN downlink messages.

www.vutility.com 22 https://github.com/the-real-vutility/payload-codecs

5.2.1 Packet 38 - Comprehensive

NOTE: The separate smaller packets are recommended for general use. In low data rate or high spreading factor conditions, this packet may fail to send due to LoRaWAN airtime restrictions. Certain LoRaWAN regions and many public networks impose stringent restrictions that necessitate longer transmit intervals.

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 38.

1-2 3-4 5-6

Voltage L1 Voltage L2 Voltage L3 uint16 An unsigned fixed-point number inMSB formatwith 10 integer and 6 fractional bits. The value is the rolling average of each RMS phase voltage since the previous transmission of this packet type. The decimal RMS Volts per phase can be calculated by the following equation:

VLN[Volts] = uint16raw

64.0

Phase Angle L1 Phase Angle L2 Phase Angle L3 uint8 An unsigned integer representing the phase angle.

The value is the rolling average of each phase angle since the previous transmission of this packet type. The angle for each phase is determined as the sinusoidal degree offset between the voltage and current waveforms. The decimal phase angle in degrees can be calculated by the following equation:

PhaseAngle[Degrees] = 360.0 255.0

× uint8raw www.vutility.com 23

Packet 38 - Comprehensive (Continued)

Byte Index

Field Type Description

10 Capacitor Voltage Scalar1 uint8 An unsigned integer representing the capacitor voltage. The capacitor voltage can be calculated by the following equation:

CapacitorVoltage[Volts] = 5.0

256.0 × uint8raw

11-12 13-14 15-16

Current L1 Current L2 Current L3 uint16 An unsigned fixed-point number inMSB formatwith 12 integer and 4 fractional bits. The value is the rolling average of each RMS phase current since the previous transmission of this packet type. The decimal RMS Amps per phase can be calculated by the following equation:

ILN[Amps] = uint16raw

16.0

Offset Ratio L1 Offset Ratio L2 Offset Ratio L3 uint8 An unsigned fixed-point number with 3 integer and 5 fractional bits. The number represents the ratio offset for the peak current above the average.

For phase i the peak RMS amperage can be calculated using the average value (Ii) offset ratio and the following equation:

IiMAX[Amps] = Ii ×

1.0 + uint8raw

32.0 www.vutility.com 24

Packet 38 - Comprehensive (Continued)

Byte Index

Field Type Description

20 Temperature Scalar2 uint8 An unsigned integer representing the device’s internal temperature. The temperature in degrees Celcius can be calculated by the following equation:

Temperature[◦C] = 120.0 255.0

× uint8raw − 40.0

[1] The capacitor voltage is provided for diagnostic purposes and does not affect device operation once it reaches 2.6V. Its steady-state voltage may vary between units and depends on the configured transmit behavior.

[2] Internal temperature sensor accuracy is ±5◦C and is intended for informational use only.

Example Packet 38 - Comprehensive

Note: Values are randomized and provided for decoder verification only.

Base64 Encoding JkVJRPdD4wnw6q4AUgETCkghLC2I

Raw Packet (Hexadecimal Bytes) [26, 45, 49, 44, F7, 43, E3, 09, F0, EA, AE, 00, 52, 01, 13, 0A, 48, 21, 2C, 2D, 88]

Decoded Values

Voltage L1 277.141V Current L1 5.125A

Voltage L2 275.859V Current L2 17.188A

Voltage L3 271.547V Current L3 164.5A

Phase Angle L1 12.706° Peak Current L1 10.410A

Phase Angle L2 338.824° Peak Current L2 40.822A

Phase Angle L3 330.353° Peak Current L3 395.828A

Capacitor Voltage 3.398V Temperature 24°C www.vutility.com 25

5.2.2 Packet 39 - Voltage and Phase Angle

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 39.

1–2 3–4 5–6

Voltage L1 Voltage L2 Voltage L3 uint16 An unsigned fixed-point number inMSB formatwith 10 integer and 6 fractional bits. The value is the rolling average of each RMS phase voltage since the previous transmission of this packet type. The decimal RMS Volts per phase can be calculated by the following equation:

VLN[Volts] = uint16raw

Phase Angle L1 Phase Angle L2 Phase Angle L3 uint8 An unsigned number representing the phase angle.

The value is the rolling average of each phase angle since the previous transmission of this packet type. The angle for each phase is determined as the sinusoidal degree offset between the voltage and current waveforms. The decimal phase angle in degrees can be calculated by the following equation:

PhaseAngle[Degrees] = 360.0 255.0

× uint8raw

10 Capacitor Voltage Scalar1 uint8 An unsigned integer representing the capacitor voltage. The capacitor voltage can be calculated by the following equation:

CapacitorVoltage[Volts] = 5.0

256.0 × uint8raw

[1] The capacitor voltage is provided for diagnostic purposes and does not affect device operation once it reaches 2.6V. Its steady-state voltage may vary between units and depends on the configured transmit behavior.

www.vutility.com 26

Example Packet 39 - Voltage and Phase Angle

Note: Values are randomized and provided for decoder verification only.

Base64 Encoding J0VJRPdD4wnw6q4=

Raw Packet (Hexadecimal Bytes) [27, 45, 49, 44, F7, 43, E3, 09, F0, EA, AE]

Decoded Values

Voltage L1 277.141V Phase Angle L1 12.706°

Voltage L2 275.859V Phase Angle L2 338.824°

Voltage L3 271.547V Phase Angle L3 330.353°

Capacitor Voltage 3.398V www.vutility.com 27

5.2.3 Packet 40 - Voltage and IEC Power Factor

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 40.

1–2 3-4 5-6

Voltage L1 Voltage L2 Voltage L3 uint16 An unsigned fixed-point number inMSB formatwith 10 integer and 6 fractional bits. The value is the rolling average of each RMS phase voltage since the previous transmission of this packet type. The decimal RMS Volts per phase can be calculated by the following equation:

VLN[Volts] = uint16raw

Power Factor L1 Power Factor L2 Power Factor L3 int8 A signed integer representing the IEC power factor.

The value is the rolling average of each phase IEC power factor as a percentage since the previous transmission of this packet type. The value will not exceed the range [-100, +100].

10 Capacitor Voltage Scalar1 uint8 An unsigned integer representing the capacitor voltage. The capacitor voltage can be calculated by the following equation:

CapacitorVoltage[Volts] = 5.0

256.0 × uint8raw

[1] The capacitor voltage is provided for diagnostic purposes and does not affect device operation once it reaches 2.6V. Its steady-state voltage may vary between units and depends on the configured transmit behavior.

www.vutility.com 28

Example Packet 40 - Voltage and IEC Power Factor

Note: Values are randomized and provided for decoder verification only.

Base64 Encoding KEVJRPdD42FdV64=

Raw Packet (Hexadecimal Bytes) [28, 45, 49, 44, F7, 43, E3, 61, 5D, 57, AE]

Decoded Values

Voltage L1 277.141V Power Factor L1 0.97

Voltage L2 275.859V Power Factor L2 0.93

Voltage L3 271.547V Power Factor L3 0.87

Capacitor Voltage 3.398V www.vutility.com 29

5.2.4 Packet 41 - Amperage and Peak Amps

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 40.

1–2 3-4 5-6

Current L1 Current L2 Current L3 uint16 An unsigned fixed-point number inMSB formatwith 12 integer and 4 fractional bits. The value is the rolling average of each RMS phase current since the previous transmission of this packet type. The decimal RMS Amps per phase can be calculated by the following equation:

ILN[Amps] = uint16raw

16.0

Offset Ratio L1 Offset Ratio L2 Offset Ratio L3 uint8 An unsigned fixed-point number with 3 integer and 5 fractional bits. The number represents the ratio offset for the peak current above the average.

For phase i the peak RMS amperage can be calculated using the average value (Ii) offset ratio and the following equation:

IiMAX[Amps] = Ii ×

1.0 + uint8raw

32.0

10 Temperature Scalar1 uint8 An unsigned integer representing the device’s internal temperature. The temperature in degrees Celcius can be calculated by the following equation:

Temperature[◦C] = 120.0 255.0

× uint8raw − 40.0

[1] Internal temperature sensor accuracy is ±5◦C and is intended for informational use only.

www.vutility.com 30

Example Packet 41 - Amperage and Peak Amps

Note: Values are randomized and provided for decoder verification only.

Base64 Encoding KQBSARMKSCEsLYg=

Raw Packet (Hexadecimal Bytes) [29, 00, 52, 01, 13, 0A, 48, 21, 2C, 2D, 88]

Decoded Values

Current L1 5.125A Peak Current L1 10.410A

Current L2 17.188A Peak Current L2 40.822A

Current L3 164.5A Peak Current L3 395.828A

Temperature 24°C www.vutility.com 31

5.2.5 Packets 42/43 - Active (Real) Energy

Note: While packets 42 and 43 contain the same data, packet 42 requires confirmation from the LNS that it has been received. If confirmation is not received, the device will retry on 1 minute intervals for up to 8 total transmissions. There are benefits and disadvantages to using confirmed data packets. While they can help ensure that the confirmed data is received, the repeated transmissions can inhibit other data packets from being sent per schedule.

Active energy accumulation is directional and in environments with energy generation (i.e. solar) the active energy accumulator may decrease and go negative if the reverse energy flow exceeds forward consumption.

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 42 for the confirmed packet and 43 for unconfirmed (standard).

1–8 Active Energy int64 An signed integer in MSB format. The value is the arithmetic sum (L1+L2+L3) of the total Active Energy accumulation in Watt-Hours since the most recent factory reset.

9–10 Average Power Factor1 int16 A signed fixed-point number in MSB format with 1 sign bit, 8 integer bits and 7 fractional bits. The value is the rolling average of the total phase power factor since the previous transmission of this packet type. The decimal power factor as a percentage can be calculated by the following equation:

PFAvg[%] = int16raw

128.0

[1] The average power factor field is only valid for a three-phase Wye system.

www.vutility.com 32

Example Packets 42/43 - Active (Real) Energy

Note: Values are randomized and provided for decoder verification only. Packet 42 is shown, change the bold base64 and hex bytes to "Kw" and "2B" respectively for packet 43.

Base64 Encoding KgAAAABJzN9YKQA=

Raw Packet (Hexadecimal Bytes) [2A, 00, 00, 00, 00, 49, CC, DF, 58, 29, 00]

Decoded Values

Active Energy 1238163288 Wh

Avg. Power Factor 83.00% www.vutility.com 33

5.2.6 Packets 44/45 - Apparent Energy

Note: While packets 44 and 45 contain the same data, packet 44 requires confirmation from the LNS that it has been received. If confirmation is not received, the device will retry on 1 minute intervals for up to 8 total transmissions. There are benefits and disadvantages to using confirmed data packets. While they can help ensure that the confirmed data is received, the repeated transmissions can inhibit other data packets from being sent per schedule.

Apparent energy accumulation is an absolute value sum of all energy passing through the meter and is strictly increasing, even in environments with reverse energy flow.

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 44 for the confirmed packet and 45 for unconfirmed (standard).

1–8 Apparent Energy int64 An unsigned integer inMSB format. The value is the arithmetic sum (L1+L2+L3) of the total Apparent Energy accumulation in Volt-Ampere-Hours since the most recent factory reset.

9–10 Average Power Factor int16 A signed fixed-point number in MSB format with 1 sign bit, 8 integer bits and 7 fractional bits. The value is the rolling average of the total phase power factor since the previous transmission of this packet type. The decimal power factor as a percentage can be calculated by the following equation:

PFAvg[%] = int16raw

128.0 www.vutility.com 34

Example Packets 44/45 - Apparent Energy

Note: Values are randomized and provided for decoder verification only. Packet 44 is shown, change the bold base64 and hex bytes to "LQ" and "2D" respectively for packet 45.

Base64 Encoding LAAAAACL0FXBKQA=

Raw Packet (Hexadecimal Bytes) [2C, 00, 00, 00, 00, 8B, D0, 55, C1, 29, 00]

Decoded Values

Active Energy 2345686465 VAh

Avg. Power Factor 83.00% www.vutility.com 35

5.2.7 Packet 46 - Startup Diagnostic

The startup diagnostic is sent as the first packet when the VoltDrop starts up and connects to LoRaWAN. It contains information about the system software versions and the reason that the device was reset in the event of system errors. This information will be requested by support engineers when diagnosing system issues.

Note: In the event that the radio module cannot communicate with the metering hardware, the Meter Firmware Hash field will read as the hexadecimal value 0xFFFF (Decimal: 65535) and the system will restart repeatedly until the situation is resolved. Check the snap-together connection between the radio module and metering hardware. Contact support if a device loop resets and sends the startup diagnostic repeatedly.

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 46.

1 Reset Reason uint8 An unsigned number indicating the reason the system was reset. (See the following table for details.)

0. Power Loss (typical startup value)

1. Hardware Reset

2. Watchdog Timer

3. Unknown Software Request

4. CPU Lock-Up

5. Hard-Fault

6. Application Request

7. Factory Reset

8. Meter Non-Responsive

9. Failed Link-Check

10. Assertion Failure

2–5 Radio Firmware Hash uint32 An unsigned integer inMSB format. Represents the unique software build identifier of the radio module firmware.

6–7 Meter Firmware Hash uint16 An unsigned integer in MSB format. Represents the unique software build identifier of the metering firmware.

8–10 Reserved N/A These bytes are reserved for internal diagnostics.

Provide them to service technicians if requested.

www.vutility.com 36

Reset Reason Details

Reset Reason Description

Power Loss The system is starting up after power has been applied. (typical)

Hardware Reset The system was reset due to diagnostic hardware.

Watchdog Timer1 The system was reset due to incorrect software operation.

Unknown Software Request The system was reset due to an untraceable software request.

(i.e. via software updater)

CPU Lock-Up1 The system was reset due to a hardware fault.

Hard-Fault1 The system was reset due to execution of an invalid operation.

Application Request The system was reset due to a traceable software request (i.e. via soft reset downlink)

Factory Reset The systemwas reset after clearing parameters due to receiving the factory reset downlink.

Meter Non-Responsive The system was reset due to failing communications with the metering hardware.

Failed Link-Check The systemwas reset after failing multiple LoRaWAN link check requests to the gateway.

Assertion Failure1 The system was reset due to a failed assertion in software.

[1] In the event that a "Watchdog Timer", "Hard-Fault", "CPU Lock-Up", or "Assertion Failure" reset occurs, please contact support and provide the raw startup diagnostic data (including reserved bytes) for analysis.

Example Packet 46 - Startup Diagnostic

Note: Values are randomized and provided for decoder verification only.

Base64 Encoding LgFwmc3jskEAAAA=

Raw Packet (Hexadecimal Bytes) [2E, 01, 70, 99, CD, E3, B2, 41, 00, 00, 00]

Decoded Values

Reset Reason 1 (Hardware Reset)

Radio Firmware Hash 0x7099CDE3

Meter Firmware Hash 0xB241 www.vutility.com 37

5.2.8 Packet 47 - Operational Diagnostic

The operational diagnostic is sent as needed when error events occur. Depending on the severity of the event, a diagnostic may be sent immediately or on a periodic schedule.

Byte Index

Field Type Description

0 Packet ID uint8 This value is equal to 47.

1–2 Condition Flags uint16 An 16-bit field of boolean flags indicating error conditions that have occurred on the radio or meter.

Flag descriptions are in the following detailed table.

3–4 Register ID uint16 Meter register ID that triggered the last timeout or failure condition indicated in the flags. ID is formatted as MSB and defaults to zero when unset.

This value is intended for support technicians.

5–10 Reserved N/A These bytes are reserved and should read as zeroes.

Condition Flag Details

"Immediate" transmit types are sent directly when the error condition occurs. "Periodic" types are sent on a 5 minute intervals as long as the condition persists.

Bit Index

Error Condition Transmit Behavior

Description

0 Invalid Downlink Immediate The previous downlink was invalid and has been discarded.

User Action: Verify and resend the downlink.

1 Radio Voltage Drop

Immediate The radio capacitor energy storage has fallen below typical operating levels. The system is likely to power-down soon.

User Action: Check that the VoltDrop is connected and powered correctly.

www.vutility.com 38

Packet 47 - Condition Flag Details (Continued)

Bit Index

Error Condition Transmit Behavior

Description

2 EEPROM Failure Immediate The radio persistent storage has failed. Accumu-lated energy readings may be lost or corrupted if the device restarts or loses power.

User Action: Log energy readings and contact support.

3 Meter Timeout Periodic The radio failed to receive a response from the metering hardware. The failed register address is reported in the “Register ID” field of the diagnostic packet User Action: Spurious errorsmay be ignored if data flow is not impacted. Persistent errors typically indicate issues with the snap-together connection between the radio and metering hardware. Check that the radio has not come loose. Contact support if error is persistent.

4 Meter NACK Periodic The radio received a negative response from the metering hardware. The failed register address is reported in the “Register ID” field of the diagnostic packet.

User Action: Spurious errorsmay be ignored if data flow is not impacted. Persistent errors of this type typically indicate incompatible firmware versions between the radio and metering hardware. Contact support if error is persistent.

5 Meter Overvoltage

Periodic The metering hardware experienced voltage above rated limits for a non-transient amount of time. This error is permanent once triggered.

User Action: Contact support.

6 Meter Not Calibrated

Periodic The metering hardware does not contain calibra-tion constants required for operation.

User Action: Contact support www.vutility.com 39

Packet 47 - Condition Flag Details (Continued)

Bit Index

Error Condition Transmit Behavior

Description

7 Phase Sequence Error

Periodic The phase relationships between inputs do not match expected offsets for a 3-phase AC Wye system.

User Action: Check ordering and connections of input phases. Incorrect ordering of phases does not impact measurements, but this error may also indicate installation issues such as a single phase connected to multiple inputs.

8 Transmit Duty-Cycle Restricted

Immediate A packet transmission was dropped because it would exceed the regulatory maximum airtime limits. This is typically caused by transmitting at low data rate due to poor link strength. Certain LoRaWAN regions and public networks may impose more stringent limits.

User Action: Spurious errorsmay be ignored if data flow is not impacted. Improve gateway positioning to increase signal integrity and data rate. Reduce transmit interval and/or avoid using the larger consolidated packet 38.

9–15 Reserved www.vutility.com 40

Example Packet 47 - Operational Diagnostic

Note: Values are randomized and provided for decoder verification only.

Base64 Encoding LwCqqlUAAAAAAAA=

Raw Packet (Hexadecimal Bytes) [2F, 00, AA, AA, 55, 00, 00, 00, 00, 00, 00]

Decoded Values

Radio Voltage Drop Meter Timeout

Meter Overvoltage Phase Sequence Error

Register ID: 0xAA55 www.vutility.com 41

5.3 Downlink Configuration Definitions

Downlinks are data packets sent from the LoRaWAN network server (LNS) to the device. The VoltDrop is configurable via several downlinks described in this section. Downlinks should be sent to FPort 3.

Note: Depending on the LNS used, the downlink may need to be encoded as Base64 to be sent.

Upper and lower case in Base64 is part of the encoding; do not modify capitalization.

5.3.1 Device Reboot (Soft Reset)

This will initiate a software reset, causing the device to rejoin the LoRaWAN network and send the startup diagnostic.

Raw Packet (Hexadecimal Bytes) Base64 Encoding

[00, 5A] AFo=

5.3.2 Factory Reset

This will initiate a factory reset. Accumulated active and apparent energies will be set to zero, the packet schedule will be reset to the default, and the device will reboot.

Raw Packet (Hexadecimal Bytes) Base64 Encoding

[00, 46] AEY=

www.vutility.com 42

5.3.3 Transmit Interval

The VoltDrop sends scheduled packets at a configurable interval, defaulting to 1 minute. Note that diagnostic packets are sent asynchronously and do not follow this interval.

Byte Index

Field Type Description

0–1 Downlink ID uint16 An unsigned 16-bit number in MSB format, equal to 0x0031 hexadecimal (Decimal: 49)

2–5 Transmit Interval uint32 An unsigned 32-bit number in MSB format. Set to the desired transmit interval in seconds, valid range is 30 up to 1800 seconds (30 minutes).

Example Transmit Interval Downlinks

Transmit Interval Raw Packet (Hexadecimal Bytes)

Base64 Encoding

1 minute (default) [00, 31, 00, 00, 00, 3C] ADEAAAA8

2 minutes [00, 31, 00, 00, 00, 78] ADEAAAB4

5 minutes [00, 31, 00, 00, 00, 2C] ADEAAAEs

15 minutes [00, 31, 00, 00, 00, 84] ADEAAAOE

30 minutes [00, 31, 00, 00, 00, 08] ADEAAAcI www.vutility.com 43

5.3.4 Data Schedule

The VoltDrop allows for configuration of the packet schedule. Each uplink packet can be identified by its unique packet ID (i.e. Packet 40 - Voltage and IEC Power Factor). These packet IDs are used when configuring a custom schedule. The system allows for scheduling up to 60 minutes of data at the default send interval of 1 minute. Note that the schedule repeats once completed.

In order to configure a custom packet schedule, the following format should be used:

Byte Index

Field Type Description

0–1 Downlink ID uint16 An unsigned 16-bit number in MSB format, equal to 0x0030 hexadecimal (Decimal: 48)

2 Packet Count uint8 An unsigned 8-bit number indicating how many packets are contained in the schedule. Maximum value is 60.

3–62 Packet ID Sequence

[uint8] Up to 60 packet ID’s to be sent in the sequence given. Invalid packet ID’s (or a zero) will be interpreted as gaps/delays in the schedule.

The packet schedule must adhere to the following rules. Schedules that do not meet the criteria will be discarded. Contact support to request aid with complicated scheduling.

1. The number of packets can not be zero.

2. The number of packets is at most 60. This enables scheduling up to 60 minutes of data at the default transmit interval of 1 minute. Note that the packet schedule repeats in a loop when completed and most use-cases will not require scheduling all 60 slots.

3. Shorter schedules should not fill all 60 slots; end the downlink after the desired number of packets have been listed.

4. Each…