ELKOR WattsOn-Mark II User Manual

PRECISION ENERGY METER

METER USER MANUAL

ELKOR TECHNOLOGIES INC. - Page 2 - WattsOn-Mark II – USER MANUAL

Installation Considerations

Installation and maintenance of the WattsOn device must only be performed by qualified, competent personnel who have appropriate training and experience with electrical high voltage and current installations. The WattsOn device must be installed in accordance with all Local and National Electrical Safety Codes.

WARNING

Failure to observe the following may result in severe injury or death:

 During normal operation of this device, hazardous voltages are present on the input terminals of the device and

throughout the connected power lines, including any potential transformers (PTs). With their primary circuit energized, current transformers (CTs) may generate high voltage when their secondary windings are open. Follow standard safety precautions while performing any installation or service work (i.e. remove line fuses, short CT secondaries, etc).

 This device is not intended for protection applications.  Do not HIPOT and/or dielectric test any of the digital outputs. Refer to this manual for the maximum voltage level

the meter can withstand.

 Do not exceed rated input signals as it may permanently damage the device.  The power supply input should be connected via a rated 12-35 VDC / 24VAC power supply and properly isolated

from the line voltage.

Danger

Line voltages up to 600 VRMS may be present on the input terminals of the device and throughout the connected line circuits during normal operation. These voltages may cause severe injury or death.

Installation and servicing must be performed only by qualified, properly trained personnel.

Limitation of Liability

Elkor Technologies Inc. (“Elkor”) reserves the right to make changes to its products and/or their specifications without notice. Elkor strongly recommends obtaining the latest version of the device specifications to assure the most current information is available to the customer. Specifications and manual are available at http://www.elkor.net

Elkor assumes no liability for applications assistance, customer’s system design, or infringement of patents or copyrights of third parties by/or arising from the use of Elkor’s devices.

ELKOR TECHNOLOGIES INC. SHALL NOT BE LIABLE FOR CONSEQUENTIAL DAMAGES SUSTAINED IN CONNECTION WITH ELKOR PRODUCTS, EXCEPT TO THE EXTENT PROHIBITED BY APPLICABLE LAW. FURTHERMORE, ELKOR NEITHER ALLOWS NOR AUTHORIZES ANY OTHER PERSON TO ASSUME FOR IT ANY SUCH OBLIGATION OR LIABILITY.

Although the information contained in this document is believed to be accurate, Elkor assumes no responsibility for any errors which may exist in this publication.

ELKOR TECHNOLOGIES INC. - Page 3 - WattsOn-Mark II – USER MANUAL

Installation Considerations ........................................................................................................................................ 3

WARNING................................................................................................................................................................ 3

Limitation of Liability ................................................................................................................................................ 3

Table of Contents .............................................................................................................................................. 4

1. Introduction .............................................................................................................................................. 5

1.1. Electrical Wiring ................................................................................................................................................ 5

1.2. Disclosure ......................................................................................................................................................... 5

1.3. Revision History ................................................................................................................................................ 5

1.4. Warranty .......................................................................................................................................................... 5

1.5. Product Description ........................................................................................................................................... 5

2. Specifications ............................................................................................................................................ 6

2.1. Indicators ......................................................................................................................................................... 7

3. Installation................................................................................................................................................ 8

3.1. Grounding Considerations .................................................................................................................................. 8

3.2. Power Supply .................................................................................................................................................... 8

3.3. Line Circuits Wiring ............................................................................................................................................ 8

3.4. Fusing of Voltage Sensing Inputs ....................................................................................................................... 8

3.5. Enclosure Mounting ........................................................................................................................................... 8

3.6. Commissioning Flowchart .................................................................................................................................. 9

3.7. Digital Communications ................................................................................................................................... 10

4. Communication ....................................................................................................................................... 11

4.1. Modbus Protocol ............................................................................................................................................. 11

4.2. Modbus Functions ........................................................................................................................................... 11

5. Register Map ........................................................................................................................................... 13

5.1. Register Addressing Conventions ...................................................................................................................... 13

5.2. Register Size ................................................................................................................................................... 13

5.3. Data Types ..................................................................................................................................................... 13

5.4. Instantaneous Data Registers .......................................................................................................................... 14

5.5. Accumulated Data Registers ............................................................................................................................. 15

5.6. Configuration and Status Registers ................................................................................................................... 21

5.7. System Registers ............................................................................................................................................. 28

5.8. Relay Output Configuration Registers ............................................................................................................... 31

6. Customizing the Register Map ................................................................................................................ 33

7. Firmware Updates and the Bootloader ................................................................................................... 35

8. Appendix A, Wiring Diagrams ................................................................................................................. 36

8.1. Four-Wire (Wye) Wiring Diagram ..................................................................................................................... 36

8.2. Three-Wire (Delta) Wiring Diagram (Three CTs) ................................................................................................ 37

8.3. Three-Wire (Delta) Wiring Diagram (Two CTs) .................................................................................................. 38

8.4. Split-Phase Wiring Diagram .............................................................................................................................. 39

8.5. CT Wiring Notes .............................................................................................................................................. 40

9. Appendix B, Modbus Protocol Details ..................................................................................................... 41

9.1. Modbus Frames ............................................................................................................................................... 41

9.2. Cyclic Redundancy Checksum .......................................................................................................................... 41

9.3. Read Holding Registers .................................................................................................................................... 42

9.4. Read Input Registers ....................................................................................................................................... 42

9.5. Write Single Register ....................................................................................................................................... 42

9.6. Write Multiple Registers ................................................................................................................................... 42

9.7. Mask Write Register ........................................................................................................................................ 43

9.8. Read/Write Multiple Registers .......................................................................................................................... 43

9.9. Diagnostic Functions ........................................................................................................................................ 44

9.10. Get Comm Event Counter............................................................................................................................... 46

9.11. Report Slave ID ............................................................................................................................................. 46

ELKOR TECHNOLOGIES INC. - Page 4 - WattsOn-Mark II – USER MANUAL

1. INTRODUCTION

Version

Date

Changes

Revision 1

October 2014

Original Version

Revision 2

December 2014

Clarified reserved registers in tables from section 5.4.1 through to 5.5.4. Corrected default threshold voltage in section 2.1 from 5V to 20V. Corrected frequency channel selection in section 5.6.15 to state that changes occur on voltages below 5V

Revision 3

February 2015

Corrected description of Report Slave ID in Appendix B to include the byte count

Revision 4

September 2015

Added Total Capacitive/Reactive Energy (FW > v10.52)

1.1. Electrical Wiring

Because of possible electrical shock or fire hazards, connection of this equipment should only be made by qualified personnel in compliance with the applicable electrical codes and standards.

1.2. Disclosure

This publication contains information proprietary to Elkor Technologies Inc. No part of this publication may be reproduced, in any form, without prior written consent from Elkor Technologies Inc.

1.3. Revision History

1.4. Warranty

The WattsOn-Mark II is warranted against defective material and workmanship. During the warranty period Elkor will repair or replace, at its option, all defective equipment that is returned freight prepaid. There will be no charge for repair provided there is no evidence that the equipment has been mishandled or abused. If the equipment is found to be in proper working order, a service fee will be billed to the customer. Warranty claims must be made via the original purchaser.

Standard Warranty duration is one (1) year from date of sale. Extended warranties are available to OEMs.

1.5. Product Description

The WattsOn-Mark II Precision Energy Meter utilizes advanced metering technology to implement a multi-functional power and energy meter into a small, cost-effective package. WattsOn-Mark II incorporates three meters into one to provide a unique solution for monitoring up to single phase, split phase and three phase loads.

The meter provides comprehensive per phase data, as well as cumulative data, including Volts, Amps, Real Power, Reactive Power, Apparent Power, Voltage Angle, Power Factor and Frequency, Quadrant, Import/Export/Net Wh/VAh and per Quadrant VARh.

WattsOn-Mark II features full four-quadrant metering, and all parameters are metered and accumulated on a per-phase basis. Additionally, the meter may be configured with per-phase CT ratios allowing for metering asymmetrical loads such as individual building branch circuits. Therefore, it is possible to use different CT sizes and ratios on each input.

The unit accepts up to 600V (line-to-line) directly without needing potential transformers. It may be configured for use with 333mV output CTs, mA output CTs (such as Elkor’s "safe" mA split and solid core CTs) or industry standard 5A CTs.

The WattsOn-Mark II meter features a proven high performance metering architecture, which allows for accurate and extremely high resolution measurements over a very wide dynamic range input. The data is updated up to two times per second. The true-RMS inputs may be used even with distorted waveforms such as those generated by variable frequency drives and SCR loads.

Information is available via the RS-485 (Modbus RTU) output port. In addition, two solid-state relay outputs are available and may be software configured for Wh pulse outputs, or alarm triggers, as well as direction of power. An on-board graphic LCD display, real-time clock and data logging is optionally available.

ELKOR TECHNOLOGIES INC. - Page 5 - WattsOn-Mark II – USER MANUAL

2. SPECIFICATIONS

Inputs

Control Power Input Rating

12-35V VDC / 24VAC, 100 mA max

System Types Supported

120/208V Delta, Wye 277/480V Delta, Wye 347/600V Delta, Wye Single-phase installations up to 347V RMS Split-phase (two phase) installations

Frequency

40-70 Hz

Voltage Input Rating

5 to 347V L-N (600 V L-L)

Voltage Continued Overload Rating

20%

Voltage Absolute Maximum Rating

450V L-N, 780V L-L

Voltage Input Impedance

1.5MΩ (line-to-neutral) minimum, 3.0MΩ (line-to-line) minimum

Voltage Wire Size

AWG 30-12, solid / stranded (AWG 16-22 recommended)

Current Input Rating

Up to 200 mA RMS (–mA model) Up to 333 mV RMS (–mV model) Up to 10A RMS (–5A model)

Current Continued Overload Rating

+20%

Current Absolute Maximum Rating

400 mA RMS (–mA model) 666 mV RMS (–mV model) 20A RMS (–5A model)

Current Burden/Input Impedance

1.5Ω total maximum(–mA model) 800kΩ minimum, 1.2MΩ typical (–mV model)

0.05Ω total maximum (–5A model)

Current Wire Size

AWG 24-12, solid / stranded (AWG12-16 recommended for 5A CTs)

Tightening Torque

7.0 Lb-In (Voltage), 4.4 Lb-In (Other)

Outputs

Serial

RS-485 2-wire Modbus RTU, 9600 (default) to 230400 baud Elkor Expansion Bus Port

Relay

2x Solid-State Relay Outputs (100 mA @ 50V max)

Indicators

LEDs for: Status, Voltage, Current, Relay State, Communication

Display

Back-lit Graphic LCD Display 128x32 (–DL models only)

Accuracy

Current (A)

0.05% typical

0.1% max

Voltage, Line-to-Neutral (V)

0.1% typical

0.2% max

Voltage, Line-to-Line (V)

0.2% typical

0.3% max

Real Power (W)

0.1% typical

0.2% max

Apparent Power (VA)

0.1% typical

0.2% max

Reactive Power (VAR)

0.1% typical

0.2% max

Energy

0.1% typical

0.2% max

Power Factor

0.2% max

Frequency

0.01% max

Sampling Rate

2 KHz

Data Update Time

2 Hz

Environmental

Operating Temperature

–40°C to +70°C

Storage Temperature

–65°C to +85°C

Humidity

10 to 90% non-condensing

Mechanical

Mass

0.15 kg (–mA and –mV models) - 0.23 kg (–5A-DL model)

Mounting

DIN Rail mounting 2-point screw mounting

Regulatory

Electromagnetic Emissions

FCC part 15 Class B (residential and industrial)

Safety

UL 508 listed

Accuracy

ANSI C12.20 Class 0.2

ELKOR TECHNOLOGIES INC. - Page 6 - WattsOn-Mark II – USER MANUAL

2.1. Indicators

Label

Color

Description

STATUS

Green/Red

Indicates the status of the device. See the Status Indicator Codes, below.

Green/Red

Indicates Modbus RS-485 communication. Green indicates transmission, red indicates reception. Solid red indicates that Modbus is wired backwards (+ and – terminals are reversed).

Green/Red

Indicates Elkor Expansion Bus communication. Green indicates transmission, red indicates reception. Solid red indicates that the Expansion bus is wired backwards (+ and – terminals are reversed).

Yellow

Indicates the state of the first relay output. Off indicates open, on indicates closed.

Yellow

Indicates the state of the second relay output. Off indicates open, on indicates closed.

3x Green

Voltage indicators. By default, the LED is on when the voltage is greater than 20V.

3x Green/Red

Current & Power Indicators. See Current & Power Indicators, below.

Code

Description

Solid green indicates that the device is operating normally.

Two periodic green blinks indicates that the meter has started in bootloader mode. See section 7, Firmware Updates and the Bootloader (p. 35) for details.

Alternating green and red indicates that the Modbus address is set to 0, which is used for debugging purposes. See section 5.7.2, Configuring Serial Parameters (p. 28) for details on using address 0.

Two periodic red blinks indicates that corrupt firmware has been on the device, halting the device in bootloader mode.

Flashing red indicates a product malfunction that prevents it from reading correctly.

Code

Description

Solid green indicates that current is present.

If voltage is present, solid green indicates that active power (kW) is being

imported

Blinking green indicates that power is being

exported

. (Voltage must be present).

Solid red indicates that active power (kW) is being

imported

, but absolute reactive

power (kVAR) exceeds absolute active power (kW). (Voltage must be present).

Blinking red indicates that active power is being

exported

, but absolute reactive power

(kVAR) exceeds absolute active power (kW). (Voltage must be present).

By default, the LED is off when the current is less than 0.1% of the full scale input.

A number of indicator LEDs are present on the WattsOn. They are described in the table below.

2.1.1. Status Indicator Codes

The status indicator uses a variety of patterns to indicate the device’s status, as described by the following table.

2.1.2. Current & Power Indicators

The WattsOn features three indicator LEDs which display the status of the metering inputs. The table below summarizes the LED states. The LED will not turn on (in any state) if the input current is less than 0.1% (default) of the full scale input.

ELKOR TECHNOLOGIES INC. - Page 7 - WattsOn-Mark II – USER MANUAL

3. INSTALLATION

3.1. Grounding Considerations

Output signal ground is usually provided by the controller (RTU, DDC, PLC etc). The output common (GND) IS ISOLATED (3500VAC minimum) from the input reference (N terminal), however the "-" terminal of the input power

supply and the output common (GND) are tied together internally.

3.2. Power Supply

The power supply must be properly isolated from the measurement line to maintain the required isolation voltage. A small dedicated transformer or DIN mount switching power supply is recommended to ensure the best isolation between system components. Contact Elkor to purchase recommended accessories.

For DC power supplies, the polarity must be observed. For AC power supplies, it must be noted that the RS-485 output common (G) and “-” power supply terminal are tied together. Care must be taken if multiple devices are powered using one AC supply to prevent shorting the supply.

The power supply may be shared by multiple devices.

3.3. Line Circuits Wiring

The WattsOn meter is a true 'three element' meter that can be used in any electrical system. For four-wire systems ('wye', with distributed neutral) the meter requires current and voltage information from each phase, therefore three current transformers (CTs) and three line voltages plus neutral must be wired to the unit.

WattsOn may be used in three wire systems ('delta', without a distributed neutral) as a 'three element' meter (three CTs required). The 5A meter version may be wired as a 'two element' meter utilizing only two CTs (and two PTs). When no neutral is present, the neutral connection should be omitted.

Standard wiring principles for electricity meters apply to the WattsOn meter, as for any other '3 element' electricity meter. The polarity of interfacing transformers must be observed. The left terminal of each current input connector is always associated with the 'X1' wire of the responding CT. Please refer to Appendix A for details on CT wiring.

All mV and mA CTs must be wired independently to the corresponding current inputs (two wires from each CT without shunts or jumpers). mA and mV CTs must components) in any way.

The use of a metering test switch containing fuses for voltage lines and shorting terminals for 5A CTs is recommended. A pre-assembled Elkor

A CT shorting mechanism is not required for mV and Elkor mA style CTs, since these are voltage clamped, however appropriate protection (fuse or breaker) for input line voltages is required.

See Section 8, Appendix A, Wiring Diagrams (p. 36) for details on wiring the meter for various system configurations.

i-BlockTM

may be used as a convenient and economical solution.

NOT

be grounded, or interconnected with each other (or any other

3.4. Fusing of Voltage Sensing Inputs

The input voltage lines should be protected as per electrical code requirements. This is also good practice to facilitate an easy disconnect means for servicing the meter. In some cases, the voltage may be tapped off of existing fuses or breakers. If this is not possible, Elkor recommends a 1A or lower fuse (fast acting) for protection of the installation wiring. The WattsOn voltage inputs are high impedance (> 1.5MΩ) and draw negligible current (less than 0.3mA max).

3.5. Enclosure Mounting

The WattsOn is housed in a UL 94V-0 plastic enclosure intended for either DIN mount installation or wall mounted installation All of the input (bottom) and output (top) signals are available on the exterior of the enclosure. The unit does not contain any user serviceable parts and thus should not be accessed by the user.

ELKOR TECHNOLOGIES INC. - Page 8 - WattsOn-Mark II – USER MANUAL

3.6. Commissioning Flowchart

Connect up to three current transformers to the current input terminals (bottom-right green) on the device. Observe the polarity as indicated on the CTs – reversing the leads or mounting the CTs backwards will result in negative power and energy accumulation.

Connect a 12-35 VDC / 24VAC power supply to the device’s black power terminal.

Connect the two or three-wire RS-485 line to the device’s top-right green terminal. The ground wire may be optional for short distances. The Modbus specification recommends the use of shielded RS-485 cabling. Twisted pair is recommended for noisy environments. Bus termination may be required for complex networks.

Connect the other end of the Modbus line to the Modbus master device (PLC, PC, etc.).

Program the CT Ratio primary (for 5A or millivolt CTs) or turn count (for milliamp CTs) into register 0x500 using the Modbus master device. See

Setting CT Ratios

(p. 21) for details. If voltage transformers are being used,

program the transformer ratio into register 0x508 and 0x509.

Read the

Debug Register

0x509 to test that the communications are functioning correctly. The register should

read 12345 (0x3039 in hexadecimal).

Configure the device’s Modbus address by setting the hardware address switch. The address of each device on the RS-485 line must be unique. If only one device on the line, it can be left at the default setting (1). Addresses from 1 to 15 can be set via the switch, and if necessary higher addresses can be set over Modbus once communication is established; see 3.7, Digital Communications (p. 10). The address must not be set to 0 for normal

For safety reasons, ensure that any live voltages are turned off while connecting the voltage leads. Connect line voltage leads to the voltage input terminals (bottom-left green. The device will accept up to 347V L-N (or 600V L-L) without a transformer. For higher voltages, potential transformers are required.

Relay outputs may be wired (for example, with pulse counters).

The following chart summarizes the procedure to install and set up the WattsOn device for basic use.

ELKOR TECHNOLOGIES INC. - Page 9 - WattsOn-Mark II – USER MANUAL

3.7. Digital Communications

Parameter

Default Setting

Modbus address

Baud rate

9600

Parity

None

Data bits

Stop bits

The WattsOn has an RS-485 port which communicates using the Modbus RTU protocol.

The RS-485 port comes factory-programmed with the indicated settings below. The baud rate, parity, and stop bit settings can be changed via Modbus; see 5.7.2, Configuring Serial Parameters (p. 28).

Every Modbus device on an RS-485 network must be assigned a unique Modbus Address. This address is used to specifically identify the target device for querying by the master. Valid Modbus addresses are between 1-247.

Using the rotary switch, addresses from 1-15 can be set. The switch indicates numbers as hexadecimal values, with 1-9 being shown as normal, “A” representing 10, “B” representing 11, and so on. When the rotary switch is set to F (15) the device will instead use an address programmed into the unit. The internally programmed address defaults to 15, to match the rotary switch setting. See section 5.7.1, Modbus Addresses above 15 (p. 28) for details on setting extended Modbus addresses using Modbus.

Address 0 is not a valid Modbus address; it is used for troubleshooting purposes only. See section 5.7.2, Configuring Serial Parameters (p. 28) for details on using address 0.

ELKOR TECHNOLOGIES INC. - Page 10 - WattsOn-Mark II – USER MANUAL

4. COMMUNICATION

Function Name

Function Code

Description

Read Holding Registers

03 (0x03)

Reads the data contained in one or more registers (identical to function 04 on this device).

Read Input Registers

04 (0x04)

Reads the data contained in one or more registers (identical to function 03 on this device).

Write Register

06 (0x06)

Writes data to a single register.

Diagnostics

08 (0x08)

Return Query Data

00 (0x00)

The Diagnostics function is a series of subfunctions that assist in diagnosing communication problems.

See Diagnostic Functions (below) for details on each one.

Clear Counters

10 (0x0A)

Bus Message Count

11 (0x0B)

Bus Comm Error Count

12 (0x0C)

Bus Exception Count

13 (0x0D)

Slave Message Count

14 (0x0E)

Get Event Counter

11 (0x0B)

Reads a count of successful messages since power-on, excluding function 11 messages.

Write Multiple Registers

16 (0x10)

Writes data to one or more registers.

Report Slave ID

17 (0x11)

Returns various information used to identify this device. See Slave ID (below).

Write Mask Register

22 (0x16)

Modifies data in a single register based on an OR mask and an AND mask.

Read/Write Registers

23 (0x17)

Writes data to one or more registers, and then reads data from one or more registers.

Read Device ID

43 (0x2B)/14 (0x0E)

Reads various text strings giving device parameters. See Device ID (next page).

Description

Sub-Function

Description

Return Query Data

00 (0x00)

Sends dummy data to the device, which is then returned as-is. Used for testing communication.

Clear Counters

10 (0x0A)

Clears all counters associated with the communication system, including the Bus Message Counter, the Bus Comm Error Counter, the Bus Exception Counter, the Slave Message Counter, and the Event Counter (also used in function 11).

Bus Message Count

11 (0x0B)

Returns the number of messages that the device has detected since power-up. These messages were not necessarily valid or addressed to this device.

Bus Comm Error Count

12 (0x0C)

Returns the number of CRC errors detected by the device since power-up. The messages containing these CRC errors were not necessarily addressed to this device.

Bus Exception Count

13 (0x0D)

Returns the number of exception responses returned by this device since power-up.

Slave Message Count

14 (0x0E)

Returns the count of messages addressed to this device that were received since power-up.

4.1. Modbus Protocol

The WattsOn communicates using Modbus RTU, a digital communication protocol over an RS-485 port. This protocol is supported by various PC software applications, PLCs, data logging devices, and other Modbus “master” devices, which can be used to communicate with the WattsOn. The WattsOn is defined as a Modbus “slave” device, meaning that it responds to queries sent by the Modbus “master” device.

A Modbus slave device defines blocks of “registers” that contain information, each with a particular address. Each register contains a 16-byte field of data which can be read by the master device. The registers defined by the WattsOn are described in section 5, Register Map (p. 13).

For technical details on the Modbus protocol, see Appendix B, Modbus Protocol Details (p. 41), or see the official Modbus Application Specification available for free from http://www.modbus.org/specs.php.

4.2. Modbus Functions

The WattsOn supports a number of different Modbus functions used to query the device or issue commands. Some Modbus software/devices require the user specify specific Modbus functions. Others are more sophisticated, and will automatically use the appropriate functions as needed, without requiring detailed knowledge of the Modbus protocol.

4.2.1. Supported Functions

The WattsOn supports the following Modbus functions:

4.2.2. Diagnostic Functions

The WattsOn implements various diagnostic functions to assist in verifying and diagnosing communication problems. The Diagnostic function is divided into a number of sub-functions each identified by a sub-function code. The following table summarizes the diagnostic sub-functions implemented by this device.

ELKOR TECHNOLOGIES INC. - Page 11 - WattsOn-Mark II – USER MANUAL

4.2.3. Slave ID

Field

Data

ID Code

130

Status

0xFF (ON) when running normally, 0x00 (OFF) when in bootloader mode.

Text String

An ASCII text string containing the name of the product, its input configuration (mA, mV, or 5A), and its hardware and software version. The string is null-terminated, meaning a 0 is transmitted after the last character. For example, “Elkor Technologies W2-M1-mA Hardware 1.00 Firmware 1.00”.

While in bootloader mode, the string returned contains the bootloader version, for example, “Elkor Technologies Bootloader 1.00”.

Object

Object ID

4.2.4. Device ID

The WattsOn implements the Read Device ID function, which provides access to various strings that identify various device properties. This is sub-function 14 (0x0E) of function 43 (0x2B), Encapsulated Interface Transport. The WattsOn implements this function at the highest Conformity Level of 0x83 (basic, regular, and extended identification, stream or individual access).

Each string, called an “object”, is accessed with a number, called the object ID. The WattsOn defines the following objects, which can be read using this function.

ELKOR TECHNOLOGIES INC. - Page 12 - WattsOn-Mark II – USER MANUAL

5. REGISTER MAP

Type

Code

Description

Unsigned Integer

Positive whole numbers (no sign). Can range from 0 to 65,535 for 16-bit registers, and 0 to 4,294,967,295 for 32-bit registers.

Signed Integer

Positive or negative whole numbers. Represented in 2’s complement format. Can range from -32,768 to +32,767 for 16-bit registers and -2,147,483,648 to +2,147,483,647 for 32-bit registers.

Floating-Point

Positive or negative decimal numbers. Represented in IEEE 754 format. Can represent values from negative infinity to positive infinity, at decreasing levels of resolution as the number because larger.

Boolean

True or false. False is represented by the value 0, true is represented by the value 1.

Examples Offset: 0x0

PLC-style: 40001 Register No: 1

Offset: 0x10 PLC-style: 40017 Register No: 17

Offset: 0x200 PLC-style: 40513 Register No: 513

5.1. Register Addressing Conventions

There are several different conventions for specifying the address of a particular register. Various conventions are used in different software programs, PLCs, and other devices. Three common conventions are described below.

 Offsets: Addresses are presented as hexadecimal numbers (shown with the “0x”

prefix) with the first address starting at address 0. This is how addresses are transmitted digitally over the serial cable, and many software packages describe Modbus addresses.

 PLC-style addresses: Addresses are presented as 5-digit decimal numbers, starting

with a “3” or a “4” indicating whether they are considered “input registers” which are read-only, or “holding registers” which are read-write (respectively). The first input register is defined as 30001, and the first holding register is defined as 40001. For ease of integration, this device treats both Holding Registers and Input Registers as identical; therefore, either 30000-based addresses or 40000-based addresses will work with the WattsOn, though only 40000-based addresses can be written to. Many PLCs and some other devices describe Modbus addresses in this manner.

 Register numbers: Addresses are presented as decimal numbers, with the first register defined as register 1.

These are similar to the PLC-style addresses described above, without “3” or “4” prefix. Some software packages describe Modbus addresses in this manner.

The address of each register is presented in the first two styles in this manual. The required convention that is used depends on the Modbus master software or device.

5.2. Register Size

Modbus registers are defined as each containing 16 bits of information. In this document, some registers are described as being 32-bits wide, rather than 16. In these cases, two consecutive registers are concatenated together in order to obtain the 32-bit value. Most modern Modbus software and hardware devices understand the notion of 32-bit registers, and will do this processing, provided the data is configured as a 32-bit register.

Example: Register 0x100 is a 32-bit register. Suppose a read of register 0x100 returns 0x0003, and a read of register 0x101 returns 0x0D40. Concatenate these two registers together to get a hexadecimal value of 0x00030D40, or a decimal value of 200,000.

By default, the higher-order 16-bit word of a 32-bit register is the register with the lower address, and the lower-order word is at the higher address. Most Modbus software and devices will interpret 32-bit registers this way. Alternatively, the WattsOn can be configured to reverse the byte ordering, so that the higher-order word is at the higher address, and the lower-order word is at the lower address. See 5.6.6, Setting 32-bit Endianness (p. 23) for details on how to configure this setting.

5.3. Data Types

Registers contain data in one of four different types. Data types are given in the register tables with a single letter code in the “Type” column to indicate the type. The types are as follows.

ELKOR TECHNOLOGIES INC. - Page 13 - WattsOn-Mark II – USER MANUAL

5.4. Instantaneous Data Registers

Name

Offset

Address

Size

Type

R/W

Units

Scale

Active Power Total

0x100

40257

32 S R W 10

Reactive Power Total

0x102

40259

32 S R

VAR

Apparent Power Total

0x104

40261

32 S R

Voltage Average

0x106

40263

32 S R V 100

Voltage L-L Average

0x108

40265

32 S R V 100

Current Average

0x10A

40267

32 S R A 1000

System Power Factor

0x10C

40269

32 S R - 10000

System Frequency

0x10E

40271

32 S R

1000

Voltage Phase Angle Average

0x110

40273

32 S R ° 10

System Quadrant

0x112

40275

32 U R - -

Reserved

0x114

40277

32 - R - -

…

Reserved

0x11E

40287

32 - R - -

Voltage A

0x120

40289

32 S R V 100

Voltage B

0x122

40291

32 S R V 100

Voltage C

0x124

40293

32 S R V 100

Voltage AB

0x126

40295

32 S R V 100

Voltage BC

0x128

40297

32 S R V 100

Voltage AC

0x12A

40299

32 S R V 100

Current A

0x12C

40301

32 S R A 1000

Current B

0x12E

40303

32 S R A 1000

Current C

0x130

40305

32 S R A 1000

Active Power A

0x132

40307

32 S R W 10

Active Power B

0x134

40309

32 S R W 10

Active Power C

0x136

40311

32 S R W 10

Reactive Power A

0x138

40313

32 S R

VAR

Reactive Power B

0x13A

40315

32 S R

VAR

Reactive Power C

0x13C

40317

32 S R

VAR

Apparent Power A

0x13E

40319

32 S R

Apparent Power B

0x140

40321

32 S R

Apparent Power C

0x142

40323

32 S R

Power Factor A

0x144

40325

32 S R - 10000

Power Factor B

0x146

40327

32 S R - 10000

Power Factor C

0x148

40329

32 S R - 10000

Voltage Phase Angle AB

0x14A

40331

32 S R ° 10

Voltage Phase Angle BC

0x14C

40333

32 S R ° 10

Voltage Phase Angle AC

0x14E

40335

32 S R ° 10

Quadrant A

0x150

40337

32 U R - -

Quadrant B

0x152

40339

32 U R - -

Quadrant C

0x154

40341

32 U R - -

Sliding Window Power

0x156

40343

32 S R W 10

Instantaneous data registers contain the real-time measurements from the input channels on the device, including current, voltage, power, power factor, and frequency. For energy registers, see 5.5, Accumulated Data Registers (p.

15). The instantaneous registers are presented in two different formats, each in a separate block of registers – as floating-point data (for modern systems), and as integer data (for systems which do not support floating-point data). It is recommended to read the floating-point data if possible, as there is then no need to scale the registers manually.

Both integer and floating-point registers incorporate the CT and PT ratios entered into the configuration registers described in section 5.6, Configuration and Status Registers (p. 21).

5.4.1. Integer Instantaneous Data Registers

The following registers are 32-bit integer representations of the measured parameters. To allow integer registers to represent decimal numbers, the integer registers are scaled according to a scaling factor. Divide the value read from these registers by the scaling factor in the

Scale

column to get a decimal value in the units specified by the

Units

column.

Example: If you read the value “4501” from the Current A register, divide 4501 by the scaling factor of 1000, to get a value of 4.501 Amps on channel A.

ELKOR TECHNOLOGIES INC. - Page 14 - WattsOn-Mark II – USER MANUAL

5.4.2. Floating-Point Instantaneous Data Registers

Name

Offset

Address

Size

Type

R/W

Units

Active Power Total

0x200

40513

32 F R

Reactive Power Total

0x202

40515

32 F R

kVAR

Apparent Power Total

0x204

40517

32 F R

kVA

Voltage Average

0x206

40519

32 F R V Voltage L-L Average

0x208

40521

32 F R

Current Average

0x20A

40523

32 F R A System Power Factor

0x20C

40525

32 F R - System Frequency

0x20E

40527

32 F R

Voltage Average Angle

0x210

40529

32 F R ° System Quadrant

0x212

40531

32 F R

Reserved

0x214

40533

32 - R

…

Reserved

0x21E

40543

32 - R

Voltage A

0x220

40545

32 F R V Voltage B

0x222

40547

32 F R V Voltage C

0x224

40549

32 F R

Voltage AB

0x226

40551

32 F R V Voltage BC

0x228

40553

32 F R

Voltage AC

0x22A

40555

32 F R V Current A

0x22C

40557

32 F R A Current B

0x22E

40559

32 F R

Current C

0x230

40561

32 F R A Active Power A

0x232

40563

32 F R

Active Power B

0x234

40565

32 F R

Active Power C

0x236

40567

32 F R

Reactive Power A

0x238

40569

32 F R

kVAR

Reactive Power B

0x23A

40571

32 F R

kVAR

Reactive Power C

0x23C

40573

32 F R

kVAR

Apparent Power A

0x23E

40575

32 F R

kVA

Apparent Power B

0x240

40577

32 F R

kVA

Apparent Power C

0x242

40579

32 F R

kVA

Power Factor A

0x244

40581

32 F R - Power Factor B

0x246

40583

32 F R

Power Factor C

0x248

40585

32 F R - Voltage Angle AB

0x24A

40587

32 F R ° Voltage Angle BC

0x24C

40589

32 F R

Voltage Angle AC

0x24E

40591

32 F R ° Quadrant A

0x250

40593

32 F R

Quadrant B

0x252

40595

32 F R - Quadrant C

0x254

40597

32 F R

Sliding Window Power

0x256

40599

32 F R

The following registers are 32-bit floating-point representations of the measured parameters, expressed in IEEE 754 format. Unlike the integer registers described above, these registers are capable of representing decimal numbers and therefore do not require any scaling.

5.5. Accumulated Data Registers

Accumulated data registers contain energy data accumulated over time from the input channels on the device, including real energy, apparent energy, and reactive energy. For instantaneous registers such as power and current, see 5.4, Instantaneous Data Registers (p. 14).

There are four blocks of accumulated data registers in total. Two blocks reflect resets – they can be reset to 0 at any time. The remaining two blocks do not reflect resets, and retain their total accumulated value despite any number of resets issued by the user. Revenue-grade metering applications or applications that do not require the ability to reset the meter should always read the non-resettable registers.

ELKOR TECHNOLOGIES INC. - Page 15 - WattsOn-Mark II – USER MANUAL

+ 33 hidden pages

ELKOR WattsOn-Mark II User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Installation Considerations

WARNING

Limitation of Liability

TABLE OF CONTENTS

1. INTRODUCTION

1.1. Electrical Wiring

1.2. Disclosure

1.3. Revision History

1.4. Warranty

1.5. Product Description

2. SPECIFICATIONS

2.1. Indicators

2.1.1. Status Indicator Codes

2.1.2. Current & Power Indicators

3. INSTALLATION

3.1. Grounding Considerations

3.2. Power Supply

3.3. Line Circuits Wiring

3.4. Fusing of Voltage Sensing Inputs

3.5. Enclosure Mounting

3.6. Commissioning Flowchart

3.7. Digital Communications

4. COMMUNICATION

4.1. Modbus Protocol

4.2. Modbus Functions

4.2.1. Supported Functions

4.2.2. Diagnostic Functions

4.2.3. Slave ID

4.2.4. Device ID

5. REGISTER MAP

5.1. Register Addressing Conventions

5.2. Register Size

5.3. Data Types

5.4. Instantaneous Data Registers

5.4.1. Integer Instantaneous Data Registers

5.4.2. Floating-Point Instantaneous Data Registers

5.5. Accumulated Data Registers