Endress+Hauser EngyVolt RV12 Operating Instructions Manual

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Operating Instructions

EngyVolt RV12

Multifunction electrical energy meter

BA01039K/09/EN/03.13
71211948

EngyVolt RV12 Table of contents

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Table of contents

1 Safety instructions .................. 4

1.1 Workplace safety ....................... 4

1.2 Requirements concerning the staff .......... 4

1.3 Operational safety ...................... 4

1.4 Designated use ........................ 4

1.5 Technical improvement .................. 5

1.6 Return ............................... 5

1.7 Notes on safety conventions and icons ....... 5

2 Identification ....................... 7

2.1 Device designation ...................... 7

2.2 Scope of delivery ....................... 7

2.3 Certificates and approvals ................ 7

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

3.1 Incoming acceptance, transport, storage ...... 8

3.2 Installation conditions ................... 8

3.3 Dimensions ........................... 8

3.4 Installation instructions .................. 9

3.5 Post-installation check ................... 9

4 Wiring ............................ 10

4.1 Supply voltage ........................ 10

4.2 Electrical connection ................... 10

4.3 Connecting the outputs ................. 13

4.4 Post-connection check .................. 14

5 Operation ......................... 15

5.1 Display ............................. 15

5.2 Operating elements .................... 15

5.3 Display mode ......................... 15

5.4 Configuration mode .................... 16

5.5 Power-up screen ...................... 17

6 Commissioning .................... 18

6.1 Post-installation check and switching on the

device .............................. 18

6.2 Menu structure ....................... 18

6.3 Device settings ........................ 20

7 Maintenance ...................... 25

8 Troubleshooting .................. 26

8.1 Spare parts .......................... 26

8.2 Return .............................. 26

8.3 Disposal ............................ 26

9 Accessories ....................... 27

10 Technical data .................... 28

11 Appendix ......................... 34

11.1 Basis of measurement and calculations ...... 34

11.2 Modbus implementation ................ 35

11.3 RS485 general information .............. 41

11.4 Modbus protocol general information ....... 43

11.5 RS485 Implementation of Johnson Controls

Metasys ............................ 55

Index .................................. 59

Safety instructions EngyVolt RV12

4

1 Safety instructions

The reliable and safe operation of the device is only ensured if the user reads these
Operating Instructions and complies with the safety instructions they contain.

1.1 Workplace safety

For work on and with the device:

‣

Wear the required personal protective equipment according to federal/national
regulations.

1.2 Requirements concerning the staff

The personnel for installation, commissioning, diagnostics and maintenance must fulfill
the following requirements:

‣

Trained, qualified specialists: must have a relevant qualification for this specific
function and task

‣

Are authorized by the plant owner/operator

‣

Are familiar with federal/national regulations

‣

Before beginning work, the specialist staff must have read and understood the
instructions in the Operating Instructions and supplementary documentation as well as
in the certificates (depending on the application)

‣

Following instructions and basic conditions

The operating personnel must fulfill the following requirements:

‣

Being instructed and authorized according to the requirements of the task by the
facility's owner-operator

‣

Following the instructions in these Operating Instructions

1.3 Operational safety

Risk of injury.

‣

Operate the device in proper technical condition and fail-safe condition only.

‣

The operator is responsible for interference-free operation of the device.

Conversions to the device

Unauthorized modifications to the device are not permitted and can lead to unforeseeable
dangers.

‣

If, despite this, modifications are required, consult with Endress+Hauser.

Repair

To ensure continued operational safety and reliability,

‣

Carry out repairs on the device only if they are expressly permitted.

‣

Observe federal/national regulations pertaining to repair of an electrical device.

‣

Use original spare parts and accessories from Endress+Hauser only.

Environmental requirements

If a plastic transmitter housing is permanently exposed to certain steam and air mixtures,
this can damage the housing.

‣

If you are unsure, please contact your Endress+Hauser Sales Center for clarification.

‣

If used in an approval-related area, observe the information on the nameplate.

1.4 Designated use

The multifunction electrical energy meter is designed to record, display and transmit
electrical measured values in low-voltage systems with a maximum nominal voltage of

EngyVolt RV12 Safety instructions

5

500 V L-L (289 V L/N), power connection via low-voltage current transformer x/5A at a
nominal frequency of 45 to 66 Hz. It is suitable for use in single-phase power systems, and
in three-phase power systems with three or four wires.

Among other values, the electrical energy meter measures the voltage, frequency, current,
power, power factor, total harmonic distortion (THD) as well as active energy and reactive
energy.

• The manufacturer accepts no liability for damages resulting from incorrect use or use
other than that designated. It is not permitted to convert or modify the device in any
way.

• The device is designed for mounting on a top-hat rail according to DIN 43880 and must
only be operated in an installed state.

1.5 Technical improvement

The manufacturer reserves the right to modify technical data without prior notice. Please
contact your sales center for information on modifications or updates to the Operating
Instructions.

1.6 Return

The device must be packed in protective packaging if it is being returned for repair, for
example. The original packaging offers the best protection. Repairs may only be performed
by your supplier's service organization.

When returning the device for repair, enclose a note with a description of the problem
and the application.

1.7 Notes on safety conventions and icons

1.7.1 Warnings

!

DANGER

Causes (/consequences)

Consequences of non-compliance (if applicable)

‣

Corrective action

‣

This symbol alerts you to a dangerous situation. Failure to avoid the situation will result
in a fatal or serious injury.

!

WARNING

Causes (/consequences)

Consequences of non-compliance (if applicable)

‣

Corrective action

‣

This symbol alerts you to a dangerous situation. Failure to avoid the situation can result
in a fatal or serious injury.

!

CAUTION

Causes (/consequences)

Consequences of non-compliance (if applicable)

‣

Corrective action

‣

This symbol alerts you to a dangerous situation. Failure to avoid this situation can
result in minor or more serious injuries.

Safety instructions EngyVolt RV12

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NOTICE

Causes (/consequences)

Consequences of non-compliance (if applicable)

‣

Corrective action

‣

This symbol alerts you to situations which may result in damage to property.

1.7.2 Document symbols

Permitted
Indicates procedures, processes or actions that are permitted.

Preferred
Indicates procedures, processes or actions that are preferred.

Forbidden
Indicates procedures, processes or actions that are forbidden.

Additional information, tips

Reference to documentation

Reference to a page in this manual

Reference to a graphic

EngyVolt RV12 Identification

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2 Identification

2.1 Device designation

2.1.1 Nameplate

RV12

Made in UK 2012

D-87484 Nesselwang

Ord. cd.: RV12-XXXX/XX
Ser. no.: XXXXXXXXXXXX
Ext. ord. cd.: X

INPUT: 100-289V AC L-N, 173-500V AC L-L
INPUT: 5A AC
FREQ.: 45-66 Hz

Caution: refer to
installation instruction

1

2

3

4

AUX: 120-350V DC, 110-400V AC, 5 VA

A0016768

 1 EngyVolt RV12 nameplate (example)

1 Device designation
2 Order code, serial number and extended order code of the device
3 Input variables and power supply
4 Year of manufacture and manufacturer address

2.2 Scope of delivery

The scope of delivery comprises:

• Multifunction electrical energy meter for top-hat rail mounting

• Brief Operating Instructions

• Comprehensive Operating instructions are available for download at www.endress.com/
download

2.3 Certificates and approvals

2.3.1 CE mark, declaration of conformity

The device is designed to meet state-of-the-art safety requirements, has been tested and
left the factory in a condition in which it is safe to operate. The device meets the relevant
standards and directives as per EN 61 010-1 "Safety requirements for electrical equipment
for measurement, control and laboratory use".

Thus, the device described in these Operating Instructions meets the legal requirements
for the EU directives. The manufacturer confirms successful testing of the device by
affixing to it the CE mark.

For an overview of all available certificates and approvals, refer to the "Technical data"
chapter.

Installation EngyVolt RV12

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3 Installation

3.1 Incoming acceptance, transport, storage

Compliance with the permitted storage and transportation conditions is mandatory.
Precise specifications are provided in the "Technical data" section (→  28).

3.1.1 Incoming acceptance

On receipt of the goods, check the following points:

• Is the packaging or the content damaged?

• Is the delivery complete? Compare the scope of delivery against the information on your
order form.

3.1.2 Transport and storage

Please note the following:
Pack the device so that is protected against impact for storage and transport. The original
packaging provides optimum protection.

3.2 Installation conditions

The device can be mounted on a standard top-hat rail.

Measuring devices must be mounted in a dry location at stable ambient temperatures that
do not exceed or drop below the range of –10 to 55 °C (14 to 131 °F). There should be
minimum tension from vibrations. If possible, the measuring device should be mounted in
such a way that the contrast of the display is not affected by direct sunlight or strong
lighting. The LCD display is optimized for vertical reading. If the display is read
horizontally, lighting conditions can affect the readability of the display.

3.3 Dimensions

58 (2.28)

48 (1.89)

32.2 (1.27)

61.5 (2.42)

45 (1.77)

mm (in)

93.6 (3.69)

N

L3 L2 L1

AUX

PULSE MODBUS CT INPUTS

B A G -I3+ -I2+ -I1+

VOLTAGE INPUTS

90.5 (3.56)

71.3 (2.81)

A0016363

 2 Device dimensions

EngyVolt RV12 Installation

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3.4 Installation instructions

1.

2.

A0016514

1. Fit the device on the top-hat rail from above.

2. Push the bottom of the device back until it locks into place.

To remove the device from the top-hat rail, lever down the black tab at the bottom of the
device (use a suitable tool such as a screwdriver).

3.5 Post-installation check

Is the device securely mounted on the top-hat rail and locked in place?

Wiring EngyVolt RV12

10

4 Wiring

!

WARNING

Danger! Electric voltage!

‣

The entire electrical connection must be performed when the device is de-energized.

‣

Establish the protective ground connection before making any other connections.

NOTICE

Cable heat load

‣

Use suitable cables for temperatures that are 5 °C (9 °F) above the ambient
temperature.

Incorrect supply voltage can damage the device or cause malfunctions

‣

Before commissioning the device, make sure that the supply voltage matches the
voltage specifications on the nameplate.

Incorrect wiring can damage the device

‣

Observe the terminal designations on the device.

Electrical overloading can damage the device

‣

Provide overcurrent protection elements for the power cables.

‣

Provide a suitable switch or power-circuit breaker for emergency shutdown in building
installations. This switch must be provided close to the device (within easy reach) and
marked as a circuit breaker.

4.1 Supply voltage

The supply voltage is designed for the range from 100 to 400 V AC and 120 to 350 V DC.
Preferably, the supply voltage should be provided from a source other than the measured
voltage. The measured voltage can be used if it is within the tolerance limits of the supply
voltage.

4.2 Electrical connection

To ensure maximum accuracy, we recommend that the current signal connecting cables
pass through additional ferrite cores (e.g. of type 742 701 110 from Würth Elektronik) at
least six times.

EngyVolt RV12 Wiring

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4.2.1 Connection in single-phase, 2-wire power network

N

L3 L2 L1

AUX

PULSE MODBUS CT INPUTS

B A G -I3+ -I2+ -I1+

L1
N

S1

P1

VOLTAGE INPUTS

1

2

3

4

4

L1
N

A0016399

 3 Connection in single-phase, 2-wire power network

1 Fast-acting fuse 1 A
2 Slow-blow fuse 1 A
3 Supply voltage
4 Load

4.2.2 Connection in 3-phase, 3-wire power network

!

WARNING

The neutral wire connection (terminal N) is indirectly connected with the voltage
input terminals (terminals L1, L2, L3). If connected to a 3-wire system, the neutral
wire adopts a potential between the other wires.

Danger! Electric voltage!

‣

If the external wiring is connected to terminal N, it must be connected either to the
neutral wire or protective ground to prevent the risk of electric shock from the neutral
terminal.

Wiring EngyVolt RV12

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N

L3 L2 L1

AUX

PULSE MODBUS CT INPUTS

S1

P1

VOLTAGE INPUTS

S1

P1

2

3

4

4

B A G -I3+ -I2+ -I1+

1

L1
L2
L3

L1

L2

L3

A0016403

 4 Connection in 3-phase, 3-wire power network

1 Fast-acting fuse 1 A
2 Slow-blow fuse 1 A
3 Supply voltage
4 Load

The "S2" secondary terminals of the current transformers are connected in the
multifunction electrical energy meter. Only one protective ground connection  must be
provided for this reason.

EngyVolt RV12 Wiring

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4.2.3 Connection in 3-phase, 4-wire power network

N

L3 L2 L1

AUX

PULSE MODBUS CT INPUTS

S1

VOLTAGE INPUTS

L1

L2

L3
N

2

3

4

4

B A G -I3+ -I2+ -I1+

1

P1

L1
L2
L3
N

S1

S1

A0016405

 5 Connection in 3-phase, 4-wire power network

1 Fast-acting fuse 1 A
2 Slow-blow fuse 1 A
3 Supply voltage
4 Load

The "S2" secondary terminals of the current transformers are connected in the
multifunction electrical energy meter. Only one protective ground connection  must be
provided for this reason.

4.3 Connecting the outputs

4.3.1 RS485 interface for communication via Modbus RTU or
Metasys N2

The RS485 Modbus RTU interface is connected to the terminals labeled A, B, G which are
provided for this purpose (→  3,  11).

A shielded, two-wire cable is recommended for the connection between the RS485 master
and the measuring device. A cable that is specially designed for connecting RS485
interfaces should be used where possible. However, satisfactory results can be achieved
with most shielded cables for connection distances of just a few meters. Cat IV network
cables also deliver satisfactory results. Given that the measuring device communicates with
an external device via an RS485 connection, distances of up to 1200 m can be covered
under good conditions. Electrical interference or other negative conditions can reduce the
distance over which reliable operation is possible.

Wiring EngyVolt RV12

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4.3.2 Pulse output

The pulse output is connected to the terminals marked "pulse" which are provided for this
purpose.

A semi-conductor relay is provided. The nominal power is 250 V, 50 mA. Connecting
cables must be as short as possible, meet the specific requirements and be filtered where
necessary.

4.4 Post-connection check

Device condition and specifications Notes

Are cables or the device damaged? Visual inspection

Electrical connection Notes

Does the supply voltage match the specifications in the "supply voltage"
section?

(→  10)

Are the mounted cables strain-relieved? -

Are the power supply and signal cables correctly connected? (→  10) and (→  13)

EngyVolt RV12 Operation

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5 Operation

5.1 Display

The display screen is used in 2 operating modes:

• Display mode (→  15) to display measured values

• Configuration mode (→  15) of the multifunction electrical energy meter. The possible

settings are described in the "Commissioning" section (→  18).

5.2 Operating elements

You can directly access various measured values via the 4 keys on the front of the
multifunction electrical energy meter. The keys are used to configure the device in the
configuration mode.

A0016376

Is used to display voltage and frequency. Press this key repeatedly to select voltage,
frequency and %THD (total harmonic distortion). This is the "Back" function in the setup
mode.

A0016377

Is used to display current. Press repeatedly to select phase and neutral currents (3P4W),
maximum values and total harmonic distortion of currents. This is the "Up" function in the
setup mode.

A0016379

Is used to display power instantaneous values. Press repeatedly to select power (W, var &
VA), power maximum values and power factor. This is the "Down" function in the setup
mode.

A0016378

Is used to display energy. Press repeatedly to select imported/exported Wh and varh.
Flashing of the current figure indicates that data is being added.
The "1%" symbol means that values < 1 %the upper range value are not included in the
energy calculation. This is the "Enter" function in the setup mode.

5.3 Display mode

The measured values are shown on the backlit liquid crystal display.

Order in which measured values are displayed in the display mode

Key View No. Description

3-phase, 4-wire

View No. Description

3-phase, 3-wire

View No. Single-phase, 2-wire

A0016376

1 V L1-N (voltage L1/N)

V L2-N (voltage L2/N)
V L3-N (voltage L3/N)

1 V L1-L2 (voltage L1/L2)

V L2-L3 (voltage L2/L3)
V L3-L1 (voltage L3/L1)

1 V L1 (voltage L1)

2 V L1-L2 (voltage L1/L2)

V L2-L3 (voltage L2/L3)
V L3-L1 (voltage L3/L1)

3 Frequency 2 Frequency 2 Frequency

4 V L1-N %THD*

(%THD voltage L1/N)
V L2-N %THD*
(%THD voltage L2/N)
V L3-N %THD*
(%THD voltage L3/N)

5 V L1-L2 %THD*

(%THD voltage L1/L2)
V L2-L3 %THD*
(%THD voltage L2/L3)
V L3-L1 %THD*
(%THD voltage L3/L1)

3 V L1-L2 %THD*

(%THD voltage L1/L2)
V L2-L3 %THD*
(%THD voltage L2/L3)
V L3-L1 %THD*
(%THD voltage L3/L1)

3 V L1 %THD*

*) %THD = % Total Harmonic Distortion

Operation EngyVolt RV12

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Key View No. Description

3-phase, 4-wire

View No. Description

3-phase, 3-wire

View No. Single-phase, 2-wire

A0016377

1 A L1 (current L1)

A L2 (current L2)
A L3 (current L3)

1 A L1 (current L1)

A L2 (current L2)
A L3 (current L3)

1 A L1 (current L1)

2 A neutral current

3 A L1 MAX

(Current L1, maximum value,
time-integrated, maximum
indicator function)
A L2 MAX
(Current L2, maximum value,
time-integrated, maximum
indicator function)
A L3 MAX
(Current L3, maximum value,
time-integrated, maximum
indicator function)

2 A L1 MAX

(Current L1, maximum value,
time-integrated, maximum
indicator function)
A L2 MAX
(Current L2, maximum value,
time-integrated, maximum
indicator function)
A L3 MAX
(Current L3, maximum value,
time-integrated, maximum
indicator function)

2 A L1 MAX

(Current L1, maximum value,
time-integrated, maximum
indicator function)

4 A neutral current MAX

(Maximum value, time­integrated, maximum indicator
function)

5 I %THD* L1

(%THD current L1)
I %THD* L2
(%THD current L2)
I %THD* L3
(%THD current L3)

3 I %THD* L1

(%THD current L1)
I %THD* L2
(%THD current L2)
I %THD* L3
(%THD current L3)

3 I %THD* L1

(%THD current L1)

A0016379

1 kW active power

kvar reactive power
kVA apparent power

1 kW active power

kvar reactive power
kVA apparent power

1 kW active power

kvar reactive power
kVA apparent power

2 kW MAX (active power,

maximum value, time­integrated, maximum indicator
function)

2 kW MAX (active power,

maximum value, time­integrated, maximum indicator
function)

2 kW MAX (active power,

maximum value, time­integrated, maximum indicator
function)

3 PF power factor (with symbol:

coil = inductive, capacitor =
capacitance)

3 PF power factor (with symbol:

coil = inductive, capacitor =
capacitance)

3 PF power factor (with symbol:

coil = inductive, capacitor =
capacitance)

A0016378

1 kWh imported electrical energy

(active component)

1 kWh imported electrical energy

(active component)

1 kWh imported electrical energy

(active component)

2 kWh exported electrical energy

(active component)

2 kWh exported electrical energy

(active component)

2 kWh exported electrical energy

(active component)

3 kvarh imported electrical energy

(reactive component)

3 kvarh imported electrical energy

(reactive component)

3 kvarh imported electrical energy

(reactive component)

4 kvarh exported electrical energy

(reactive component)

4 kvarh exported electrical energy

(reactive component)

4 kvarh exported electrical energy

(reactive component)

*) %THD = % Total Harmonic Distortion

5.4 Configuration mode

The abbreviation for the parameter is displayed in the top display row in the configuration
mode. The middle row displays the parameter value. The bottom row is used to confirm
the set value of the parameter.

To enter the configuration mode, press and hold the and keys simultaneously for 5
seconds. The screen to enter the 4-digit password is displayed. No default password is set.
A password can be used to prevent unauthorized access to the device settings. Once the
correct password has been entered, the device is on the first level of the menu structure. If

EngyVolt RV12 Operation

17

a password was not configured for the device beforehand, the setup is called up by
pressing the key four times.

The parameter to be configured is selected with the and keys. When the key is
pressed, the parameter is selected and the user enters the second level of the menu
structure. Values can be changed at this level, such as the values of the system
configuration, for example. There is a third level in the menu structure for some
parameters, such as the parameters for communication. This level is reached in the same
way. Once the necessary settings have been made, press the key to return to the first level
in the menu structure.

Generally speaking, the and keys change the value of the parameter; the key
confirms the change / setting and skips to the next display screen (next parameter).

You can exit the configuration mode at any time by pressing the and keys
simultaneously for 5 seconds. Any changes that have already been made are retained. You
can also exit the configuration mode by repeatedly pressing the key. In both cases, the
device switches back to the last measured values displayed.

The possible settings are described in the "Commissioning" section (→  18).

5.4.1 Entering numbers

Users must frequently change digits in the configuration mode, usually in the middle row
of numbers.

The key is used to increase and the key to decrease a value.

The current digit to be changed flashes on the screen. Pressing the key accepts the set
value and switches to the next digit. In each particular row of numbers, the digits are set in
succession from left to right.

Pressing the key takes you back to the previous digit.

Once the last digit has been accepted, "SET" is displayed in the bottom row of the display.

5.5 Power-up screen

After powering up the energy meter (switching on the supply voltage), a number of
screens are displayed by way of a self-test.

1st screen: All the LCD segments are displayed. This is used as a self-test for the display.

2nd screen: The firmware version of the energy meter is displayed.

3rd screen: Displays the result of the self-test when powering up the energy meter.

The device then switches to the first measured value display and displays the voltage
values.

Commissioning EngyVolt RV12

18

6 Commissioning

6.1 Post-installation check and switching on the device

Perform all the final checks before commissioning the device.

• Checklist for "post-installation check" (→  9)

• Checklist for "post-connection check" (→  14)

When the operating voltage is applied, a number of screens are first displayed by way of a
self-test (→  17).

If you are commissioning the device for the first time, program the setup as described in
the following sections. If you are commissioning a device that is already configured, the
device starts measuring immediately as defined in the settings and the values are shown
on the display.

6.2 Menu structure

First level Second level Third level

CHNG PASS
Change password

NPWd
(new password)

Change the value of the password.
Range for selection: 0 to 9 999

Main menu Password entry SYS (system configuration) Choose from:

• 1P2W (single-phase, 2-wire)

• 3P3W (3-phase, 3-wire)

• 3P4W (3-phase, 4-wire)

CT (current transformer primary
value)

Change the value. Range for
selection: 1 to 9 999 A

dIT (integration time of average
values for maximum indicator
function)

Choose from:

• 60 minutes

• 30 minutes

• 20 minutes

• 15 minutes

• 10 minutes

• 8 minutes

• 5 minutes

• OFF

RSET (reset) Choose from:

• dmd (maximum time-integrated
average values - maximum
indicator function)

• ALL

• hour (kWh & kvarh)

COMS (communication) FMT (protocol) Choose from:

• Modb (Modbus RTU)

• N2 (Johnson Controls Metasys
N2)

bAUd (baud rate) Choose from:

• 2 400

• 4 800

• 9 600

• 19 200

• 38 400

PARI (parity) Choose from:

• None

• Odd

• Even

EngyVolt RV12 Commissioning

19

First level Second level Third level

STOP (stop bits) Choose from:

• 1

• 2

Addr (device address) Choose value from between

1 to 247

RLY (relay) OP1 (value assignment to pulse

output relay 1)

Choose from:

• NONE

• kWh EXPORT

• kWh IMPORT

• kvarh EXPORT

• kvarh IMPORT

RATE (pulse value) Choose from:

• 0.1

• 1

• 10

• 100

• 1 000

PULS (pulse length) Choose from:

• 60 ms

• 100 ms

• 200 ms

NRGY (energy) Choose from:

• KILO

• MEGA

Lmt Choose from:

• OFF

• ON

TEST Choose from:

• disp ON (tests the segments of
the LC display)

• disp TOGL (display toggle. Tests
the segments of the LC display
alternately)

• PHAS SEQ (checks the phase
sequence)

SOFT (software) Displays the version number of the

internal software (firmware)

6.2.1 Configuration example for the current transformer primary
value

1.

A0016388

Press the and keys simultaneously and hold for 5 seconds.


A0016389

The screen to enter the password is displayed.

2. To enter the default password "0000" which is set at the factory, press the key four
times or enter a password that has already been configured and press to confirm.

Commissioning EngyVolt RV12

20



A0016390

The screen to make the settings for the system configuration is displayed.

3. Repeatedly press the key until the screen to set the current transformer primary
value "CT" is displayed.



A

A0016391

4. Press the key.
 The first digit starts flashing.

5. Use the and keys to set the desired value.

6. Press the key to confirm the set value.
 The next digit starts flashing.

7. Repeat this procedure until the last digit has been set and confirmed.
 The set value is displayed as follows, for example: 0100 = 100 A, 1000 = 1 000 A,

etc. "SET" now also appears on the display.

The current transformer primary value is now configured. Press the key to return to the
first level in the menu structure. Other parameters can now be selected for configuration
in the first level.

If no more settings need to be made, press the key again to switch to the display mode.

6.3 Device settings

Calling up the Setup menu

1. Press the and keys simultaneously for 5 seconds.
 The screen to enter the password is displayed.

2. To enter the default password "0000" which is set at the factory, press the key four
times or enter a password that has already been configured and press to confirm.

 The screen to make the settings for the system configuration is displayed.

6.3.1 Changing the password - CHNG PASS

1. Call up the Setup menu.

2. Press the key.
 CHNG PASS is displayed.

3. Press the key.
 The first digit starts flashing.

4. Use the and keys to select the value of the first digit.

5. Press the key to confirm.
 The next digit starts flashing.

6. Repeat this procedure until the last digit has been set and confirmed.
 "SET" now also appears on the display.

EngyVolt RV12 Commissioning

21

6.3.2 System configuration - SYS

1. Call up the Setup menu.

2. Press the key.

3. Use the and keys to choose from the following configuration options: 1P2W
(single-phase, 2-wire = alternating current system), 3P3W (3-phase, 3-wire = three­phase system without a neutral wire), 3P4W (3-phase, 4-wire = three-phase system
with a neutral wire)

4. Press the key to confirm your selection.

"SET" is displayed.

6.3.3 Current transformer primary value (CT)

The transformer primary current must be configured in the range from 1/5 A to 9 999/5 A
to ensure current, power and energy values are displayed and recorded correctly. The setup
sequence is explained in the (→  19) configuration example. Factory setting "0005".

6.3.4 Setting the demand integration time (maximum indicator
function) - dIT

This function specifies the integration time for determining the maximum value for the
current and power (details, ). The values are displayed with "minutes" as the unit. Factory
setting "60".

1. Call up the Setup menu.

2. Press the or keys until dIT is displayed.

3. Press the key.

4. Use the and keys to choose from the following configuration options: 60, 30,
20, 15, 10, 8, 5, OFF (= no integration time, the maximum value displayed refers to
the peak value measured directly)

5. Press the key to confirm your selection.

"SET" is displayed.

6.3.5 Reset – RSET

This function resets saved values.

1. Call up the Setup menu.

2. Press the or keys until RSET is displayed.

3. Press the key. Initial display: "dmd"

4. Use the and keys to choose from the following functions: dmd (reset the
maximum values), ALL (reset kWh, kvarh and maximum values), hour (reset kWh
and kvarh)

5. Press the key to reset the value.

"RSET" is displayed.

6.3.6 Communication settings – COMS

This function is used to make the settings for the RS485 interface which enables the
device to communicate via the Modbus or the Metasys N2 protocol.

1. Call up the Setup menu.

2. Press the or keys until COMS is displayed.

3. Press the key.

Commissioning EngyVolt RV12

22

4. Press the or keys until the desired parameter is displayed.

5. Use the key to start configuring the parameter.

6. Proceed as described in the following sections.

Protocol - PROT

The multifunction electrical energy meter is designed for communication via the RS485
interface via Modbus RTU or alternatively via Metasys N2.

1. Use the and keys to choose from the following values: Modb (Modbus protocol),
N2 (Metasys N2 protocol)

2. Press the key to confirm your selection.
 If "N2" is selected, it is only possible to configure the device address (→  22).

The other communication parameters cannot be modified.

"SET" is displayed.

Setting the baud rate - bAUd

The baud rate needed for Modbus RTU communication via the RS485 interface is selected
in this function. Factory setting: "9600"

1. Use the and keys to choose from the following values: 2400, 4800, 9600,
19200, 38400.

2. Press the key to confirm your selection.

"SET" is displayed.

Setting the parity - PARI

This function sets the parity of the RS485 interface. Factory setting: "NONE"

1. Use the and keys to choose from the following values: None, Odd, Even.

2. Press the key to confirm your selection.

"SET" is displayed.

Stop bits - STOP

This function sets the number of stop bits for communication via the RS485 interface. As a
prerequisite, the parity must be set to "NONE". Factory setting: "1"

1. Use the and keys to choose from the following values: 1 = 1 stop bit, 2 = 2 stop
bits.

2. Press the key to confirm your selection.

"SET" is displayed.

Setting the device address - Addr

The device address must be configured for the multifunction electrical energy meter to
communicate in a Modbus RTU or a Metasys N2 network. Factory setting: "1", display: "001"

The possible setting for Modbus is between 1 and 247, and between 1 and 255 for
Metasys N2.

1. The first digit starts flashing once the parameter has been called up. Use the and

keys to set the desired value.

2. Press the key to confirm.
 The next digit starts flashing.

3. Set all 3 digits as required.

4. Press the key to confirm.

EngyVolt RV12 Commissioning

23

"SET" is displayed.

Setting the floating point - Ordr

This function displays the direction of the floating point. Changes to the setting cannot be
made from the energy meter. This setting can only be changed if an RS485 interface is
available and the device is integrated into a Modbus RTU network.

6.3.7 Setting the relay output - RLY

This function defines the settings for the output relay (pulse output for energy).

1. Call up the Setup menu.

2. Press the or keys until RLY is displayed.

3. Press the key. Initial display: "IMPORT", "RLY", "kWh"

4. Press the key again to assign the desired function to the pulse output.

5. Use the and keys to choose from the following values: kwH IMPORT (= use as
pulse output for kWh Import), kWh EXPORT (= use as pulse output for kWh Export),
kvarh IMPORT (= use as pulse output for kvarh Import), kvarh EXPORT (= use as pulse
output for kvarh Export), NONE (= not used)

6. Press the key to confirm your selection.

"SET" is displayed. The device goes to the next parameter "RATE".

Pulse rate - RATE

This function defines the pulse rate of the pulse output. Factory setting: "1"

1. Press the key.

2. Use the and keys to choose from the following values: 0.1 (= 1 pulse
corresponds to 0.1 kWh / kvarh, 1 (= 1 pulse corresponds to 1 kWh / kvarh), 10 (= 1
pulse corresponds to 10 kWh / varh, 100 (= 1 pulse corresponds to
100 kWh / kvarh), 1000 (= 1 pulse corresponds to 1 000 kWh / kvarh).

3. Press the key to confirm your selection.

"SET" is displayed. The device goes to the next parameter "PULS".

Pulse length - PULS

This function defines the length of a pulse. Values displayed are in the unit "ms". Factory
setting: "200"

1. Press the key.

2. Use the and keys to choose from the following values: 60, 100, 200

3. Press the key to confirm your setting.

"SET" is displayed. The device returns to the first menu level.

6.3.8 Setting the display of energy values – NRGY and setting the
measurement limit (low energy cut-off) - Lmt

This function specifies whether the energy values are displayed with the "k" or "M" sign
(kWh & kvarh MWh & Mvarh).

1. Call up the Setup menu.

2. Press the or keys until NRGY is displayed.

3. Press the key. To skip the setting and continue configuring the "Lmt" press the or
key instead.

Commissioning EngyVolt RV12

24

4. Use the and keys to choose from the following values: KILO (for kWh / kvarh), X
1 (for Wh / varh), MEGA (for MWh / Mvarh).

5. Press the key to confirm your selection.
 "SET" is displayed. The device goes to the next parameter "Lmt".

6. Press the key.
 The display shows "Lmt" at the top and "ON" in the middle row. In addition "1 %" is

displayed on the bottom left.

7. Press the or keys to switch between "ON" and "OFF".
 If Lmt is active, "1 %" appears on the bottom left of the display. The function is

used to activate measurement signal suppression to suppress incorrect
measurements caused by noise on the measuring cables. This can be required if
the measuring cables - particularly the cables between the multifunction electrical
energy meter and the external current transformers are not shielded and/or are
routed in the immediate vicinity of the primary circuits. The 1% limit always
refers to the full scale value of the power measurement, which results from the
maximum input voltage and the set transformer primary current, while taking the
interlinkage factor into consideration if necessary. If the function is switched on,
"1 %" also appears on the bottom left of the display in the display mode.

8. Press the key to confirm your selection.

"SET" is displayed. The device returns to the first menu level.

6.3.9 Self-test – TEST

This screen contains several functions for performing self-tests on the multifunction
electrical energy meter.

1. Call up the Setup menu.

2. Press the or keys until TEST is displayed.

3. Press the key.

4. Use the and keys to choose from the following values: diSP ON (when selected
by pressing the key, all the segments of the LCD display are switched on to allow
users to detect a segment failure); diSP TOGL (when selected by pressing the key,
the display alternates between two different display modes. This helps the user
identify whether individual segments do not switch off); PHAS SEQ (when selected by
pressing the key, this function checks whether the voltage and current connections
have been established correctly on the energy meter. PSEQ (phase sequence), V 123, I
123 is displayed if all the connections are correct. If PSEQ, V 132, I 123, for example,
is displayed, this indicates that a voltage connection is faulty. If PSEQ, V 12_, I 123,
for example, is displayed, this indicates that a voltage connection is missing.

6.3.10 Displaying the software version – SOFT

This function directly displays the version of the internal software (firmware).

1. Call up the Setup menu.

2. Press the or keys until SOFT is displayed.

3. Press the key.

EngyVolt RV12 Maintenance

25

7 Maintenance

!

WARNING

The device is energized.

Danger! Risk of electric shock!

‣

Before performing any cleaning work on the device, the device must be de-energized.
Live transformer cables must never be opened to remove any dust or dirt that may have
accumulated.

In normal use, the measuring device does not require any maintenance.

The front of the measuring device should be wiped with a dry cloth only. Use minimum
pressure and never apply pressure to the tinted viewing window. If necessary, the rear can
also be wiped with a dry cloth. Only isopropyl alcohol can be used as a cleaning agent and
should be used sparingly. Never use water. If the rear of the device or the terminals should
be accidentally contaminated with water, the measuring device must be dried carefully
before further service. If it is suspected that water or another contaminant might have
entered the device, the device must be examined and overhauled at the factory.

All terminals must be examined regularly for corrosion and to ensure that the terminal
connections have not become loose. This is particularly important if the device is exposed
to vibrations.

Troubleshooting EngyVolt RV12

26

8 Troubleshooting

8.1 Spare parts

No spare parts are available for the EngyVolt devices since the devices do not contain any
components that can be replaced or configured by the user.

8.2 Return

Observe the following points when returning the device:

• Contact your Endress+Hauser Sales Center to obtain information about the procedure
and basic conditions.

• Enclose a description of the error if sending in a device for repair.

8.3 Disposal

The device contains electronic components and must therefore be disposed of as electronic
waste. Please pay particular attention to the national disposal regulations in your country.

EngyVolt RV12 Accessories

27

9 Accessories

No accessories are available for this device.

Technical data EngyVolt RV12

28

10 Technical data

10.1 Input

Measured variable Measured process variables

Current (L1, L2, L3,), voltage (L1/N, L2/N, L3/N or L1/L2, L2/L3, L3/L1 respectively),
frequency in low-voltage systems

Calculated process variables

EngyVolt RV12: active, reactive and apparent power, power factor (Cos-Phi), imported and
exported active and reactive energy, total harmonic distortion (current L1, L2, L3; voltage
L1/N, L2/N, L3/N or L1/L2, L2/L3, L3/L1 respectively), neutral current, max. current (L1,
L2, L3, N)

1)

, max. active power

1)

.

EngyVolt RV15: active, reactive and apparent power, total harmonic distortion (current L1,
L2, L3; voltage L1/N, L2/N, L3/N or L1/L2, L2/L3, L3/L1 respectively), active and reactive
energy, neutral current, max. current (L1, L2, L3, N)

1)

, max. active power

1)

.

Measuring range

Nominal voltage 100 to 289 V AC L-N (173 to 500 V AC L-L)

Voltage measuring range 25 to 600 V

Maximum short-duration
overvoltage

2 x nominal voltage for 1-second application repeated 5 times in 5-minute
intervals

Nominal current (secondary) 5 A AC RMS

Secondary current measuring
range

0.05 to 6 A

Maximum short-duration
overcurrent

10 x nominal current for 1-second application repeated 5 times in 5-minute
intervals

Primary current measuring
range

1 to 9 999 A (per phase)

Frequency 45 to 66 Hz

Nominal power (secondary) 1 445 W (3-phase 4 325 W)

Power measuring range
(secondary)

14.45 to 2 080 W (3-phase: 43.25 to 6 228 W)

1)

Power measuring range
(primary)

5 to 12 450 000 W (12.45 MW)

1)

Power consumption voltage
circuits

<0.2 VA per phase

Power consumption current
circuits

<0.6 VA per phase

1) depending on CT

Energy counter 0 to 9 999 999.9 Wh, kWh, MWh / varh, kvarh, Mvarh

1) calculated from the integrated averages and representation as maximum value over an adjustable interval of 5, 8, 10, 15, 20, 30, 60 min

EngyVolt RV12 Technical data

29

10.2 Output

Output signal Pulse output

Number EngyVolt RV12: 1

EngyVolt RV15: max. 2 (optional, via extension modules)

Contact load 50 mA maximum at 250 V AC

Version Semiconductor relay

RS485 MODBUS

Number EngyVolt RV12: 1

EngyVolt RV15: 1 (optional, via extension module)

Type Two-wire, half-duplex

Baud rate 2400, 4800, 9600, 19200, 38400

10.3 Power supply

Supply voltage

AC nominal voltage 110 to 400 V AC ±10 %

DC nominal voltage 120 to 350 V DC ±20 %

Power consumption 5 VA

Electrical connection The measuring device is designed exclusively for operation on external current

converters.

The multifunction EngyVolt RV12 and RV15 electrical energy meters are suitable for
single-phase and three-phase power systems with 3 or 4 wires.

The "S2" secondary terminals of the current converters are connected in the electrical
energy meter. Only one protective ground connection  is provided for this reason.

Terminals Screw-clamp terminals 0.05 to 2.5 mm² (30 to 14 AWG)

10.4 Performance characteristics

Reference operating
conditions

Reference temperature 23 °C ±1 °C (73.4 °F ±1.8 °F)

Input wave form 50 or 60 Hz ±2 %

Sinusoidal (distortion factor < 0.005)

Supply voltage Nominal voltage ±1 %

Supply voltage frequency (with
AC)

Nominal frequency ±1 %

Supply voltage wave form Sinusoidal (distortion factor < 0.05)

Technical data EngyVolt RV12

30

Maximum measured error Extended measured error: IEC 688: 1992

Current (A) 0.5 % of nominal current

Voltage (V) 0.5 % of max. nominal voltage (4 % for I2 in 3-phase 3-wire operation)

Calculated neutral current (A) 4 % of nominal current

Frequency (Hz) 0.1 Hz

Power factor (PF = Cos-Phi) 0 to 1

Power factor is only indicated when the measured VA is over 3 % of range
maximum

Active power (W) ±1 % of nominal power

Reactive power (var) ±1 % of nominal power

Apparent power (VA) ±1 % of nominal power

Active energy (kWh) Class 1 (IEC 62053-21)

Reactive energy (kvarh) ±1 % of measuring range

THD 1 % up to 31st harmonic

Display repetition rate

1 s typically up to >99 % of the full scale value

Measurement and calculation interval

Max. 300 ms (maximum with %THD measurement)

Influence of ambient
temperature

Current and voltage: 0.013 %/°C (0.0072 %/°F) of nominal value

Power: 0.018 %/°C (0.01 %/°F) of measuring range

Error change due to
variation of an influence
quantity in the manner
described in Section 6 of
IEC 688:1992

2 x error allowed for the reference condition applied in the test. Error due to temperature
variation as above.

Error in measurement
when a measurand is
within its measuring range,
but outside its reference
range

2 x error allowed at the end of the reference range adjacent to the section of the
measuring range, where the measurand is currently operating / being tested.

Warm-up period 1 minute

10.5 Installation

Mounting location EngyVolt RV12

Housing for top hat rail mounting as per DIN 43880

Orientation Vertical

EngyVolt RV12 Technical data

31

10.6 Environment

Ambient temperature
range

–10 to 55 °C (14 to 131 °F)

Storage temperature –20 to 70 °C (–4 to 158 °F)

Humidity 0 to 90 %, non-condensing

Altitude Up to 2 000 m (6 560 ft)

Degree of protection

EngyVolt RV12 EngyVolt RV15

IP30 minimum Degree of protection at front IP52

Degree of protection at rear IP30

Shock resistance 30 g in 3 planes

Vibration resistance 10 to 50 Hz, IEC 60068-2-6, 2 g

Electromagnetic
compatibility

EMC emissions: BS EN 61326, Class A

Interference immunity: BS EN 61326, Class A

Dielectric strength 3.25 kV for 1 minute between communication outputs and measuring inputs,

communication outputs and supply voltage. Supply voltage and measuring inputs

10.7 Mechanical construction

Dimensions EngyVolt RV12 (top-hat rail)

58 (2.28)

48 (1.89)

32.2 (1.27)

61.5 (2.42)

45 (1.77)

mm (in)

93.6 (3.69)

N

L3 L2 L1

AUX

PULSE MODBUS CT INPUTS

B A G -I3+ -I2+ -I1+

VOLTAGE INPUTS

90.5 (3.56)

71.3 (2.81)

A0016363

 6 Device dimensions

Weight 300 g (0.66 lb)

Technical data EngyVolt RV12

32

Materials Polycarbonate as per UL94V0

10.8 Operability

Local operation

N

L3 L2 L1

AUX

PULSE MODBUS CT INPUTS

B A G -I3+ -I2+ -I1+

VOLTAGE INPUTS

1

2

3

RV12

RV15

A0016505

 7 Display and operating elements of the EngyVolt devices

1 Three-line display
2 Symbol for parameter displayed
3 Operating keys

The display screen is used in 2 operating modes:

• Display mode to indicate measured values

• Configuration mode of the multifunction electrical energy meter

Display mode

The measured values are shown on the backlit liquid crystal display. The user can call up
and run through 15 different views using the operating elements on the front panel.

Configuration mode

The abbreviation for the parameter is displayed in the top display row in the configuration
mode. The middle row displays the parameter value. The bottom row is used to confirm
the set value of the parameter. Generally speaking, the "A" and "P/PF" keys change the
value of the parameter; the "E" key confirms the change / setting and skips to the next
display screen (next parameter).

EngyVolt RV12 Technical data

33

10.9 Certificates and approvals

 mark Declaration of Conformity

The product meets the requirements of the harmonized European standards.

As such, it complies with the legal specifications of the EC directives.

The manufacturer confirms successful testing of the product by affixing to it the  mark.

Other standards and
guidelines

• IEC 60529:
Degrees of protection provided by enclosures (IP code)

• IEC 61010-1: 2001
Safety requirements for electrical equipment for measurement, control and laboratory
use

Appendix EngyVolt RV12

34

11 Appendix

11.1 Basis of measurement and calculations

11.1.1 Phase to Phase voltages for 3 phase 4 wire devices

Phase to Phase voltages are measured directly and calculated as RMS values. Situations
where the phases are not spaced 120 degrees apart (e.g. 4 wire open delta) are indicated
correctly.

11.1.2 Reactive and Apparent Power

Active powers are calculated directly by multiplication of voltage and current samples.
Reactive powers are calculated using the frequency corrected quarter phase time delay
method. Apparent power is calculated as the square root of the sum of the squares of
active and reactive powers.

11.1.3 Energy resolution

Cumulative energy counts are reported using the standard IEEE floating point format.
Reported energy values in excess of 1 000 000 one million may show a small non
cumulative error in the integer digits due to the limitations of the number format.
Internally the count is maintained with greater precision. The reporting error is less than 1
part per 1 000 000 and is automatically corrected when the count increases.

11.1.4 Power factor

The magnitude of Per Phase Power Factor is derived from the per phase active power and
per phase reactive power. The power factor value sign is set to negative for an inductive
load and positive for a capacitive load. The magnitude of the System Power Factor is
derived from the sum of the per phase active power and per phase reactive power.
Individual phases whose apparent power is less than 2 % of nominal are not included in
power factor determinations. The system power factor value sign is set to negative for an
inductive load and positive for a capacitive load. The load type, capacitive or inductive, is
determined from the signs of the sums of the relevant active powers and reactive powers.
If both signs are the same, then the load is inductive, if the signs are different then the
load is capacitive. The magnitude of the phase angle is the ArcCos of the power factor. Its
sign is taken as the opposite of the VAr's sign.

11.1.5 Maximum demand (drag indicator)

The maximum power consumption of an installation is provided as power utilities often
levy related charges. Many utilities use a thermal maximum demand indicator (MDI) to
measure this peak power consumption. An MDI averages the power consumed over a
number of minutes, reflecting the thermal load that the demand places on the supply
system. The Integra Ci3 digital meter uses a sliding window algorithm to simulate the
characteristics of a thermal MDI instrument, with the demand period being updated every
minute.

Demand Integration Times can be set to various values. Maximum Demand is the
maximum power or current demand that has occurred since the unit was last reset. This is
maintained as a continuous record of the highest demand value that has been reached.
Note: During the initial period when the “sliding window” does not yet contain a full set of
readings (e.g. during initial commissioning). Then maximum demands may not be true
due to the absence of immediate historical data.

EngyVolt RV12 Appendix

35

11.1.6 Total harmonic distortion – THD

The calculation used for Total Harmonic Distortion is: THD = ((RMS of total waveform –
RMS of fundamental) / RMS of total waveform) x 100. This is often referred to as THD–R,
and lies in the range 0 to 100 %. THD measurement is subject to the 'range of use' limits.
The device may give erratic or incorrect readings where the THD is very high and the
fundamental is essentially absent. For low signal levels the noise contributions from the
signal may represent a significant portion of the “RMS of total waveform” and may thus
generate unexpectedly high values of THD. In this case the product will produce a display
of 0 (zero). Typically, display of THD will only produce the 0 (zero) value when the THD
calculation has been suppressed due to a low signal level being detected. It should also be
noted that spurious signals (for example, switching spikes) may be included in the “RMS of
the total waveform” and will be used in the calculation of THD. The display of THD may be
seen to fluctuate under these conditions.

11.1.7 Testing the phase sequence

The voltage and current inputs must be greater than 5 % of nominal for the test to operate
reliably.

In the 3 phase 4 wire operating mode the measured values are referenced from L1.

For the voltage sequence test, the phase of L2 relative to L1 must be within the window
240 ±48 degrees and L3 relative to L1 must be within the window 120 ±48 degrees to
record the sequence V123.

Alternatively, the phase of L2 relative to L1 must be within the window 120 ±48 degrees
and L3 relative to L1 must be within the window 240 ±48 degrees to record the sequence
V132.

For the current sequence test, the phase of I1 relative to L1 must be within the window 0
±48 degrees, I2 relative to L1 must be within the window 240 ±48 degrees, and I3 relative
to L1 must be within the window 120 ±120 degrees to record the sequence i123.

Alternatively the phase of I1 relative to L1 must be within the window 0 ±48 degrees, I2
relative to L1 must be within the window 120 ±48 degrees, and I3 relative to L1 must be
within the window 240 ±48 degrees to record the sequence i132.

In the 3 phase 3 wire operating mode measurements are referenced from L1-L2.

For the voltage sequence test, the phase of L2-L3 relative to L1-L2 must be within the
window 240 ±48 degrees L3-L1 relative to L1-L2 must be within the window 120 ±48
degrees to record the sequence V123.

Alternatively, the phase of L2-L3 relative to L1-L2 must be within the window 120 ±48
and L3 relative to L1-L2 must be within the window 240 ±48 degrees to record the
sequence V132.

For the current sequence test, the phase of I1 relative to L1-L2 must be within the window
330 ±48 degrees, I2 relative to L1-L2 must be within the window 210 ±48 degrees, and I3
relative to L1-L2 must be within the window 90 ±48 degrees to record the sequence i123.

Alternatively, the phase of I1 relative to L1-L2 must be within the window 330 ±48
degrees, I2 relative to L1-L2 must be within the window 90 ±48 degrees, and I3 relative to
L1-L2 must be within the window 210 ±48 degrees to record the sequence i132.

11.2 Modbus implementation

11.2.1 Modbus protocol overview

This section provides basic information for interfacing a multifunctional electrical energy
meter to a Modbus protocol network. If background information or more details of the
EngyVolt implementation is required please refer to the following sections of this
document. EngyVolt devices offer the option of an RS485 communication facility for direct

Appendix EngyVolt RV12

36

connection to SCADA or other communications systems using the Modbus Protocol RTU
slave protocol. The Modbus Protocol establishes the format for the master's query by
placing into it the device address, a function code defining the requested action, any data
to be sent, and an error checking field. The slave's response message is also constructed
using Modbus Protocol. It contains fields confirming the action taken, any data to be
returned, and an error-checking field. If an error occurs in receipt of the message, the
device will make no response. If the device is unable to perform the requested action, it will
construct an error message and send it as the response.

The electrical interface is 2-wire RS485, via 3 screw terminals. Connection should be made
using twisted pair screened cable and the following electrical data:

Nominal inductivity 0.2 µH/ft

Nominal capacity line-line 24 pF/ft

Maximum operating voltage 300 V RMS

All "A" and "B" connections are daisy chained together. The screens should also be
connected to the “Gnd” terminal. To avoid the possibility of loop currents, an Earth
connection should be made at only one point on the network. Line topology may or may
not require terminating loads depending on the type and length of cable used. Loop (ring)
topology does not require any termination load. The impedance of the termination load
should match the impedance of the cable and be at both ends of the line. The cable should
be terminated at each end with a 120 Ω resistor. The load capacity of the resistor should
be 0.25 W. A total maximum length of 1 200 m (3 900 ft) is allowed for the RS485
network. A maximum of 32 electrical nodes can be connected, including the controller.
The address of each EngyVolt device can be set to any value between 1 and 247. Broadcast
mode (address 0) is not supported. The maximum latency time of an EngyVolt device is
60 ms, i.e. this is the amount of time that can pass before the first response character is
output. The supervisory program must allow this period of time to elapse before assuming
that the device is not going to respond.

The format for each byte in RTU mode is:

Coding system 8-bit per byte

Data format 4 bytes (2 registers) per parameter.

Floating point format (to IEEE 754)
Most significant register first (Default).
The default may be changed if required - See Holding Register "Register Order" .

Error check field 2 byte Cyclical Redundancy Check (CRC)

Framing 1 start bit

8 data bits, least significant bit sent first
1 bit for even/odd parity (or no parity)
1 stop bit if parity is used; 1 or 2 bits if no parity

Data coding

All data values in the EngyVolt device are transferred as 32 bit IEEE 754 floating point
numbers, (input and output) therefore each device value is transferred using two Modbus
protocol registers. All register read requests and data write requests must specify an even
number of registers. Attempts to read/write an odd number of registers prompt the device
to return a Modbus protocol exception message.

The multifunctional electrical energy meters can transfer a maximum of 40 values in a
single transaction, therefore the maximum number of registers requestable is 80.
Exceeding this limit prompts the device to generate an exception response.

Data transmission speed is selectable between 2400, 4800, 9600, 19200 and 38400
baud.

EngyVolt RV12 Appendix

37

11.2.2 Input registers

Input registers are used to indicate the present values of the measured and calculated
electrical quantities. Each parameter is held in two consecutive 16 bit registers. The
following table details the 3X register address, and the values of the address bytes within
the message. A tick () in the column indicates that the parameter is valid for the
particular wiring system. Any parameter with a cross () will return the value Zero. Each
parameter is held in the 3X registers. Modbus Protocol Function Code 04 is used to access
all parameters.

For example, to request Amps 1 (current Phase1)Start address = 0006

No of registers = 0002

Amps 2 (current Phase2)Start address = 0008

No of registers = 0002

Each request for data must be restricted to 40 parameters or less. Exceeding the 40
parameter limit will cause a Modbus Protocol exception code to be returned.

Address

(Register)

Parameter

number

EngyVolt input register parameter description Modbus-Startadresse Hex 3 Ø 3 Ø 1 Ø

Unit Hi Byte Lo Byte 4W3W2

W

30001 1 Phase 1 line to neutral volts Volt 00 00   

30003 2 Phase 2 line to neutral volts Volt 00 02   

30005 3 Phase 3 line to neutral volts Volt 00 04   

30007 4 Phase 1 current Ampere 00 06   

30009 5 Phase 2 current Ampere 00 08   

30011 6 Phase 3 current Ampere 00 0A   

30013 7 Phase 1 power Watt 00 0C   

30015 8 Phase 2 power Watt 00 0E   

30017 9 Phase 3 power Watt 00 10   

30019 10 Phase 1 volt amps VA 00 12   

30021 11 Phase 2 volt amps VA 00 14   

30023 12 Phase 3 volt amps VA 00 16   

30025 13 Phase 1 volt amps reactive Var 00 18   

30027 14 Phase 2 volt amps reactive Var 00 1A   

30029 15 Phase 3 volt amps reactive var 00 1C   

30031 16 Phase 1 power factor (*1). - 00 1E   

30033 17 Phase 2 power factor (*1) - 00 20   

30035 18 Phase 3 power factor (*1) - 00 22   

30037 19 Phase 1 phase angle Degrees 00 24   

30039 20 Phase 2 phase angle Degrees 00 26   

30041 21 Phase 3 phase angle Degrees 00 28   

30043 22 Average line to neutral volts Volt 00 2A   

30047 24 Average line current Ampere 00 2E   

30049 25 Sum of line currents Ampere 00 30   

30053 27 Total system power. Watt 00 34   

30057 29 Total system volt amps VA 00 38   

30061 31 Total system Var. var 00 3C   

Appendix EngyVolt RV12

38

Address

(Register)

Parameter

number

EngyVolt input register parameter description Modbus-Startadresse Hex 3 Ø 3 Ø 1 Ø

Unit Hi Byte Lo Byte 4W3W2

W

30063 32 Total system power factor (*1) - 00 3E   

30067 34 Total system phase angle Degrees 00 42   

30071 36 Frequency of supply voltages Hz 00 46   

30073 37 Import Wh since last reset (*2) kWh/MWh 00 48   

30075 38 Export Wh since last reset (*2) kWh/MWh 00 4A   

30077 39 Import varh since last reset (*2) kvarh/Mvarh 00 4C   

30079 40 Export varh since last reset (*2) kvarh/Mvarh 00 4E   

30081 41 VAh since last reset (*2) kVAh/MVAh 00 50   

30083 42 Ah since last reset (*3) Ah/kAh 00 52   

30085 43 Total system power demand Δt (*4) Watt 00 54   

30087 44 Maximum total system power demand Δt (*4) Watt 00 56   

30101 51 Total system VA demand Δt VA 00 64   

30103 52 Maximum total system VA demand Δt VA 00 66   

30105 53 Neutral current demand Δt Ampere 00 68   

30107 54 Maximum neutral current demand Δt Ampere 00 6A   

30201 101 Line 1 to Line 2 volts Volt 00 C8   

30203 102 Line 2 to Line 3 volts Volt 00 CA   

30205 103 Line 3 to Line 1 volts Volt 00 CC   

30207 104 Average line to line volts Volt 00 CE   

30225 113 Neutral current Ampere 00 E0   

30235 118 Phase 1 L/N volts THD % 00 EA   

30237 119 Phase 2 L/N volts THD % 00 EC   

30239 120 Phase 3 L/N volts THD % 00 EE   

30241 121 Phase 1 Current THD % 00 F0   

30243 122 Phase 2 Current THD % 00 F2   

30245 123 Phase 3 Current THD % 00 F4   

30249 125 Average line to neutral volts THD % 00 F8   

30251 126 Average line current THD % 00 FA   

30255 128 -Total system power factor (*5) Degrees 00 FE   

30259 130 Phase 1 current demand Δt Ampere 01 02   

30261 131 Phase 2 current demand Δt Ampere 01 04   

30263 132 Phase 3 current demand Δt Ampere 01 06   

30265 133 Maximum phase 1 current demand Δt Ampere 01 08   

30267 134 Maximum phase 2 current demand Δt Ampere 01 0A   

30269 135 Maximum phase 3 current demand Δt Ampere 01 0C   

30335 168 Line 1 to line 2 volts THD % 01 4E   

30337 169 Line 2 to line 3 volts THD % 01 50   

30339 170 Line 3 to line 1 volts THD % 01 52   

30341 171 Average line to line volts THD % 01 54   

EngyVolt RV12 Appendix

39

*1) The power factor has its sign adjusted to indicate the nature of the load. Positive for capacitive and

negative for inductive.

2*) There is a user option to select either k or M for the energy prefix.

3*) The same user option as in 2 above gives a prefix of none or k for Amphours

4*) The power sum demand calculation is for import power only.

5*) The negative total system power factor is a sign inverted version of parameter 32, the magnitude is

the same as parameter 32.

6*) There is a user option to select None, k or M for the energy prefix.

11.2.3 Modbus protocol holding registers and EngyVolt set up

Holding registers are used to store and display instrument configuration settings. All
holding registers not listed in the table below should be considered as reserved for
manufacturer use and no attempt should be made to modify their values. The holding
register parameters may be viewed or changed using the Modbus Protocol. Each
parameter is held in two consecutive 4X registers. Modbus Protocol Function Code 03 is
used to read the parameter and Function Code 16 is used to write. Write to only one
parameter per message.

Address

(Register)

Parameter

number

Parameter

Holding register

Modbus start

address Hex

Valid range Mode

High
Byte

Low
Byte

40001 1 Demand time (Δt) 00 00 Read minutes into first demand calculation.

When the Demand Time reaches the Demand
Period then the demand values are valid.

ro

40003 2 Demand period (Δt) 00 02 Write demand period: 0, 5, 8, 10, 15, 20, 30

or 60 minutes.
Default: 60 minutes.
Setting the period to 0 will cause the demand
to show the current parameter value, and
demand max to show the maximum
parameter value since last demand reset.

r/w

40007 4 System Volts 00 06 289 (3p4w or 1p2w)

500 (3p3w)

ro

40009 5 System current 00 08 Valid range 1 to 9 999 A. r/w

40011 6 System type 00 0A 3p4w = 3

3p3w = 2
1p2w = 1

r/w

40013 7 Relay pulse width 00 0C Write relay on period in milliseconds: 60,

100, 200
Default: 200

r/w

40015 8 Password lock 00 0E Write any value to password lock protected

registers.
Read password lock status:
0 = locked
1 = unlocked
Reading will also reset the password timeout
back to one minute.

r/w

40019 10 Network parity stop 00 12 Write the network port parity/stop bits for

Modbus Protocol, where:
0 = One stop bit and no parity, default.
1 = One stop bit and even parity.
2 = One stop bit and odd parity.
3 = Two stop bits and no parity.
Requires a restart to become effective.

r/w

Appendix EngyVolt RV12

40

Address

(Register)

Parameter

number

Parameter

Holding register

Modbus start

address Hex

Valid range Mode

High
Byte

Low

Byte

40021 11 Note address 00 14 Write the network port node address.

Default: 1
Valid range 1 to 247.
Requires a restart to become effective. Note,
both the Modbus Protocol and Johnson
Controls node addresses can be changed via
the display setup menus.

r/w

40023 12 Relay pulse divisor 00 16 Write pulse divisor index:

N = 2 to 6 in Wh/10N.
Default: 3

r/w

40025 13 Password 00 18 Write password for access to protected

registers.
Default: 0000
Read zero. Reading will also reset the
password timeout back to one minute.

r/w

40029 15 Network baud rate 00 1C Write the network port baud rate for Modbus

Protocol.
Valid values:
0 = 2400 baud
1 = 4800 baud
2 = 9600 baud (default)
3 = 19200 baud
4 = 38400 baud
Requires a restart to become effective.

r/w

40031 16 Energy units prefix 00 1E Write the units prefix for energy output

values.
0 = no prefix (e.g. Wh)
1 = k prefix (e.g. kWh)
2 = M (e.g. MWh)

r/w

40033 17 Low power limit override 00 20 0 = limit on 1% symbol off

1 = limit off 1% symbol on
Default = 0

r/w

40037 19 System power 00 24 Read the total system power,

e.g. 3p4w returns System Volts x System
Amps x 3.

ro

40041 21 Register order 00 28 Write: 2141 only r/w

40043 22 High serial number 00 2A 0 - 16,777,215 ro

40045 23 Low serial number 00 2C 0 - 16,777,215 ro

40087 44 Relay1 energy type 00 56 Modbus Protocol input parameter for pulse

relay 1:
0 = relay off
37 = Import Wh
38 = Export Wh
39 = Import varh
40 = Export varh
Default = 38

r/w

40217 109 Reset logged data 00 D8 Write 1 to reset energy r/w

Register order

Register order controls the order in which the device receives or sends floating-point
numbers: - normal or reversed register order. In normal mode, the two registers that make
up a floating point number are sent most significant register first. In reversed register
mode, the two registers that make up a floating point number are sent least significant
register first. To set the mode, write the value '2141.0' into this register - the instrument

EngyVolt RV12 Appendix

41

will detect the order used to send this value and set that order for all Modbus Protocol
transactions involving floating point numbers.

It is perfectly feasible to change EngyVolt devices set-up using a general purpose Modbus
Protocol master, but often easier to use the device display, especially for gaining password
protected access.

Password

Some of the parameters described above are password protected and thus require the
password to be entered at the Password register before they can be changed. The default
password is 0000. When the password has been entered it will timeout in one minute
unless the Password or Password Lock register is read to reset the timeout timer. Once the
required changes have been made to the protected parameters the password lock should
be reapplied by

• allowing the password to timeout, or

• writing any value to the Password Lock register, or

• power cycling the instrument.

11.3 RS485 general information

Some of the information in this section relates to other product families, and is included to
assist where a mixed network is implemented.

RS485 or EIA (Electronic Industries Association) RS485 is a balanced line, half-duplex
transmission system allowing transmission distances of up to 1 200 m (3 900 ft). The
following table summarises the RS-485 Standard:

PARAMETER Value

Mode of Operation Differential

Number of Drivers and Receivers 32 Drivers, 32 Receivers

Maximum Cable Length 1 200 m (3 900 ft)

Maximum Data Rate 10 Mbaud

Maximum Common Mode Voltage 12 to –7 V

Minimum Driver Output Levels (Loaded) ±1.5 V

Minimum Driver Output Levels (Unloaded) ±6 V

Drive Load Minimum 60 Ω

Driver Output Short Circuit Current Limit 150 mA to GND

250 mA to 12 V
250 mA to –7 V

Minimum Receiver Input Resistance 12 kΩ

Receiver Sensitivity ±200 mV

Further information relating to RS485 may be obtained from either the EIA or the various
RS485 device manufacturers.

11.3.1 Half duplex

Half duplex is a system in which one or more transmitters (talkers) can communicate with
one or more receivers (listeners) with only one transmitter being active at any one time.
For example, a “conversation” is started by asking a question, the person who has asked
the question will then listen until he gets an answer or until he decides that the individual
who was asked the question is not going to reply. In a 485 network the “master” will start
the “conversation” with a “query” addressed to a specific “slave”, the “master” will then
listen for the “slave’s” response. If the “slave” does not respond within a pre-defined

Appendix EngyVolt RV12

42

period, (set by control software in the “master”), the “master” will abandon the
“conversation”.

11.3.2 Connecting the instruments

Screened twisted pair cable should be used. For longer cable runs or noisier environments,
use of a cable specifically designed for RS485 may be necessary to achieve optimum
performance. All “A” terminals should be connected together using one conductor of the
twisted pair cable, all “B” terminals should be connected together using the other
conductor in the pair. A line as described in (→  35) or any other line with equal
specification and a characteristic impedance of 120 Ω is recommended. The cable should
be terminated at each end with a 120 Ω, min. 0.25 W, resistor and a capacitor with 1 nF in
series with the resistor.

2

B A Gnd

B AGnd

2

B A Gnd

2

B A Gnd

1

1 nF 1 nF

120

W

120

W

A0016443

 8 Modbus connection

1 Modbus Master
2 EngyVolt Modbus Slave

There must be no more than two wires connected to each terminal, this ensures that a
“Daisy Chain or “straight line” configuration is used. A “Star” or a network with “Stubs
(Tees)” is not recommended as reflections within the cable may result in data corruption.

A0016444

 9 Correct straight line connection

A0016445

 10 Incorrect star or stubs connection

11.3.3 A and B terminals

The A and B connections to the EngyVolt devices can be identified by the signals present
on them whilst there is activity on the RS485 bus.

EngyVolt RV12 Appendix

43

1

2

3

A0016446

 11 RS485 signal

1 Start bit
2 Idle State (A) = no signal level on A
3 Idle State (B) = no signal level on

11.3.4 Troubleshooting

This section contains general information. Specific notes for your individual system can be
obtained from the technical support of the software used or from your system integrator.

• Start with a simple network, one master and one slave. With EngyVolt devices this is
easily achieved as the network can be left intact whilst individual instruments are
disconnected by removing the RS485 connection from the instrument.

• Check that the network is connected together correctly as described in (→  42).

• Confirm that the data “transmitted” onto the RS485 is not echoed back to the PC on the
RS232 lines. (This facility is sometimes a link option within the converter). Many PC
based packages seem to not perform well when they receive an echo of the message they
are transmitting.

• Confirm that the address of the instrument is the same as the “master” is expecting.

• If the “network” operates with one instrument but not more than one check that each
instrument has a unique address.

• Each request for data must be restricted to 40 parameters. Violating this requirement
will impact the performance of the instrument and may result in a response time in
excess of the specification.

• Check that the Modbus Protocol mode (RTU or ASCII) and serial parameters (baud rate,
number of data bits, number of stop bits and parity) are the same for all devices on the
network.

• Check that the “master” is requesting floating-point variables (pairs of registers placed
on floating point boundaries) and is not “splitting” floating point variables.

• Check that the floating-point byte order expected by the “master” is the same as that
used by EngyVolt device. (Various software systems can use a number of formats.)

• If possible obtain a second RS232 to RS485 converter and connect it between the RS485
bus and an additional PC equipped with a software package, which can display the data
on the bus. Check for the existence of valid requests.

• Especially for converters with USB connection, experience has shown that data
transmission may be incorrect. Due to the variety of converters on the market a general
type recommendation cannot be made. Use of a RS485/RS232 converter for connection
to the serial PC interface is recommended.

11.4 Modbus protocol general information

Communication on a Modbus Protocol Network is initiated (started) by a “Master” sending
a query to a “Slave”. The “Slave“, which is constantly monitoring the network for queries
addressed to it, will respond by performing the requested action and sending a response
back to the ”Master”. Only the “Master” can initiate a query.

In the Modbus Protocol the master can address individual slaves, or, using a special
“Broadcast” address, can initiate a broadcast message to all slaves. The EngyVolt devices
do not support the broadcast address.

Appendix EngyVolt RV12

44

11.4.1 Modbus data format

The Modbus Protocol defines the format for the master’s query and the slave’s response.
The query contains the device (or broadcast) address, a function code defining the
requested action, any data to be sent, and an error-checking field. The response contains
fields confirming the action taken, any data to be returned, and an error-checking field. If
an error occurred in receipt of the message then the message is ignored, if the slave is
unable to perform the requested action, then it will construct an error message and send it
as its response. The Modbus Protocol functions used by the EngyVolt devices copy 16 bit
register values between master and slaves. However, the data used by the EngyVolt device
is in 32 bit IEEE 754 floating point format. Thus each instrument parameter is
conceptually held in two adjacent Modbus Protocol registers.

Query

The following example illustrates a request for a single floating point parameter i.e. two
16-bit Modbus Protocol Registers.

First Byte Last Byte

"Slave"
address

Function
code

Start
address
(Hi)

Start
address
(Lo)

Number of
points (Hi)

Number of
points (Lo)

Error
check
(Lo)

Error check
(Hi)

"Slave" address:

8-bit value representing the slave being addressed (1 to 247), 0 is reserved for the
broadcast address. The EngyVolt devices do not support the broadcast address.

Function code:

8-bit value telling the addressed slave what action is to be performed. (3, 4, 8 or 16 are
valid)

Start address (Hi):

The top (most significant) eight bits of a 16-bit number specifying the start address of the
data being requested.

Start address (Lo):

The bottom (least significant) eight bits of a 16-bit number specifying the start address of
the data being requested. As registers are used in pairs and start at zero, then this must be
an even number.

Number of points (Hi):

The top (most significant) eight bits of a 16-bit number specifying the number of registers
being requested.

Number of points (Lo):

The bottom (least significant) eight bits of a 16-bit number specifying the number of
registers being requested. As registers are used in pairs, then this must be an even
number.

Error check (Lo):

The bottom (least significant) eight bits of a 16-bit number representing the error check
value.

EngyVolt RV12 Appendix

45

Error check (Hi):

The top (most significant) eight bits of a 16-bit number representing the error check value.

Response

The example illustrates the normal response to a request for a single floating point
parameter i.e. two 16-bit Modbus Protocol Registers.

First Byte Last Byte

"Slave" Function

code

Byte
count

First
register
(Hi)

First
register
(Lo)

Second
register
(Hi)

Second
register
(Lo)

Error check
(Lo)

Error
check (Hi)

"Slave" address:

8-bit value representing the address of slave that is responding.

Function code:

8-bit value which, when a copy of the function code in the query, indicates that the slave
recognized the query and has responded. (See also Exception Response (→  46)).

Byte count:

8-bit value indicating the number of data bytes contained within this response

First register (Hi)

2)

:

The top (most significant) eight bits of a 16-bit number representing the first register
requested in the query.

First register (Lo)

2)

:

The bottom (least significant) eight bits of a 16-bit number representing the first register
requested in the query.

Second register (Hi)

2)

:

The top (most significant) eight bits of a 16-bit number representing the second register
requested in the query.

Second register (Lo)

2)

:

The bottom (least significant) eight bits of a 16-bit number representing the second
register requested in the query.

Error check (Lo):

The bottom (least significant) eight bits of a 16-bit number representing the error check
value.

Error check (Hi)

2)

:

The top (most significant) eight bits of a 16-bit number representing the error check value.

2) Together, these four bytes represent the value of the floating point parameter requested in the query.

Appendix EngyVolt RV12

46

Exception response

If an error is detected in the content of the query (excluding parity errors and error check
mismatch), then an error response (called an exception response), will be sent to the
master. The exception response is identified by the function code being a copy of the query
function code but with the most-significant bit set. The data contained in an exception
response is a single byte error code.

First Byte Last Byte

"Slave" address Function code Error code Error check (Lo) Error check (Hi)

"Slave" address:

8-bit value representing the address of slave that is responding.

Function code:

8 bit value which is the function code in the query OR'ed with 80 hex, indicating that the
slave either does not recognize the query or could not carry out the action requested.

Error code:

-bit value indicating the nature of the exception detected, see table of error codes
(→  54).

Error check (Lo):

The bottom (least significant) eight bits of a 16-bit number representing the error check
value.

Error check (Hi):

The top (most significant) eight bits of a 16-bit number representing the error check value.

11.4.2 Serial transmission modes

There are two Modbus Protocol serial transmission modes, ASCII and RTU. EngyVolt
devices do not support the ASCII mode.

In RTU (Remote Terminal Unit) mode, each 8-bit byte is used in the full binary range and
is not limited to ASCII characters as in ASCII Mode. The greater data density allows better
data throughput for the same baud rate, however each message must be transmitted in a
continuous stream. This is very unlikely to be a problem for modern communications
equipment.

Coding system Full 8-bit binary per byte. In this document, the value of each byte will be shown as two

hexadecimal characters each in the range 0-9 or A-F.

Line protocol 1 start bit, followed by the 8 data bits. The 8 data bits are sent with least significant bit

first.

User option of parity
and stop bits:

a) no parity & 2 stop bits
b) no parity & 1 stop bit
c) even parity & 1 stop bit
d) odd parity & 1 stop bit

User option of baud
rate

a) 2 400 b) 4 800
c) 9 600 d) 19 200

The baud rate, parity and stop bits must be selected to match the master’s settings.

EngyVolt RV12 Appendix

47

11.4.3 Modbus protocol message timing

A Modbus protocol message has defined beginning and ending points. The receiving
device recognizes the start of the message, reads the “Slave Address” to determine if they
are being addressed and knowing when the message is completed they can use the Error
Check bytes and parity bits to confirm the integrity of the message. If the Error Check or
parity fails then the message is discarded.

In RTU mode, messages start with a silent interval of at least 3.5 character times. The first
byte of a message is then transmitted, the device address. Master and slave devices
monitor the network continuously, including during the ‘silent’ intervals. When the first
byte (the address byte) is received, each device checks it to find out if it is the addressed
device. If the device determines that it is the one being addressed it records the whole
message and acts accordingly, if it is not being addressed it continues monitoring for the
next message.

Following the last transmitted byte, a silent interval of at least 3.5 character times marks
the end of the message. A new message can begin after this interval.

The entire message must be transmitted as a continuous stream. If a silent interval of
more than 2.5 character times occurs before completion of the message, the receiving
device flushes the incomplete message and assumes that the next byte will be the address
byte of a new message. Similarly, if a new message begins earlier than 3.5 character times
following a previous message, the receiving device may consider it a continuation of the
previous message. This will result in an error, as the value in the final CRC field will not be
valid for the combined messages.

11.4.4 How characters are transmitted serially

When messages are transmitted on standard Modbus protocol serial networks each byte is
sent in this order (left to right):

Transmit Character = Start Bit + Data Byte + Parity Bit + 1 Stop Bit (11 bits total):

Least

Signific

ant Bit

(LSB)

Most

Signific

ant Bit
(MSB)

Start 1 2 3 4 5 6 7 8 Parity Stop

Transmit Character = Start Bit + Data Byte + 2 Stop Bits (11 bits total):

Least

Signific

ant Bit

(LSB)

Most

Signific

ant Bit
(MSB)

Start 1 2 3 4 5 6 7 8 Stop Stop

Transmit Character = Start Bit + Data Byte + 1 Stop Bit (10 bits total):

Least

Significa

nt Bit
(LSB)

Most

Significa

nt Bit

(MSB)

Start 1 2 3 4 5 6 7 8 Stop

The master is configured by the user to wait for a predetermined timeout interval. The
master will wait for this period of time before deciding that the slave is not going to
respond and that the transaction should be aborted. Care must be taken when determining

Appendix EngyVolt RV12

48

the timeout period from both the master and the slaves’ specifications. The slave may
define the ‘response time’ as being the period from the receipt of the last bit of the query
to the transmission of the first bit of the response. The master may define the ‘response
time’ as period between transmitting the first bit of the query to the receipt of the last bit
of the response. It can be seen that message transmission time, which is a function of the
baud rate, must be included in the timeout calculation.

Query transmission

time

Slave

processing time

Response transmission

time

Query Response

Start of
query

Query received
by slave

Start of
response

Response received

by master

A0016524-EN

 12 Modbus data transmission

11.4.5 Error checking methods

Standard Modbus protocol serial networks use two error checking processes, the error
check bytes mentioned above check message integrity whilst Parity checking (even or odd)
can be applied to each byte in the message.

Parity checking

If parity checking is enabled – by selecting either Even or Odd Parity - the quantity of “1’s”
will be counted in the data portion of each transmit character. The parity bit will then be
set to a 0 or 1 to result in an Even or Odd total of “1’s”.

Note that parity checking can only detect an error if an odd number of bits are picked up or
dropped in a transmit character during transmission, if for example two 1’s are corrupted
to 0’s the parity check will not find the error. If No Parity checking is specified, no parity
bit is transmitted and no parity check can be made. Also, if No Parity checking is specified
and one stop bit is selected the transmit character is effectively shortened by one bit.

CRC checking

The error check bytes of the Modbus Protocol messages contain a Cyclical Redundancy
Check (CRC) value that is used to check the content of the entire message. The error check
bytes must always be present to comply with the Modbus Protocol, there is no option to
disable it. The error check bytes represent a 16-bit binary value, calculated by the
transmitting device. The receiving device must recalculate the CRC during receipt of the
message and compare the calculated value to the value received in the error check bytes. If
the two values are not equal, the message should be discarded.

The error check calculation is started by first pre-loading a 16-bit register to all 1’s (i.e.
Hex (FFFF)) each successive 8-bit byte of the message is applied to the current contents of
the register.

Only the eight bits of data in each transmit character are used for generating the CRC,
start bits, stop bits and the parity bit, if one is used, are not included in the error check
bytes. During generation of the error check bytes, each 8-bit message byte is exclusive
OR'ed with the lower half of the 16 bit register.

The register is then shifted eight times in the direction of the least significant bit (LSB),
with a zero filled into the most significant bit (MSB) position. After each shift the LSB
prior to the shift is extracted and examined. If the LSB was a 1, the register is then
exclusive OR'ed with a pre-set, fixed value. If the LSB was a 0, no exclusive OR takes place.

EngyVolt RV12 Appendix

49

This process is repeated until all eight shifts have been performed. After the last shift, the
next 8-bit message byte is exclusive OR'ed with the lower half of the 16 bit register, and
the process repeated. The final contents of the register, after all the bytes of the message
have been applied, is the error check value. In the following pseudo code “ErrorWord” is a
16-bit value representing the error check values.

BEGIN

ErrorWord = Hex (FFFF)
FOR Each byte in message

ErrorWord = ErrorWord XOR byte in message
FOR Each bit in byte

LSB = ErrorWord AND Hex (0001)
IF LSB = 1 THEN ErrorWord = ErrorWord – 1
ErrorWord = ErrorWord / 2
IF LSB = 1 THEN ErrorWord = ErrorWord XOR Hex (A001)

NEXT bit in byte

NEXT Byte in message

END

11.4.6 Function codes

The function code part of a Modbus Protocol message defines the action to be taken by the
slave. EngyVolt devices support the following function codes:

Code Modbus protocol name Description

03 Read Holding Registers Read the contents of read/write location (4X

references).

04 Read Input Registers Read the contents of read only location (3X

references).

08 Diagnostics Only sub-function zero is supported. This returns the

data element of the query unchanged.

16 Pre-set Multiple Registers Set the contents of read/write location (4X

references).

11.4.7 IEEE floating point format

The Modbus Protocol defines 16 bit “Registers” for the data variables. A 16-bit number
would prove too restrictive, for energy parameters for example, as the maximum range of
a 16-bit number is 65535. However, there are a number of approaches that have been
adopted to overcome this restriction. Integra Digital meters use two consecutive registers
to represent a floating-point number, effectively expanding the range to ±1 x 1037.

The values produced by EngyVolt devices can be used directly without any requirement to
“scale” the values, for example, the units for the voltage parameters are volts, the units for
the power parameters are watts etc.

What is a floating point number?

A floating-point number is a number with two parts, a mantissa and an exponent and is
written in the form 1.234 x 105. The mantissa (1.234 in this example) must have the
decimal point moved to the right with the number of places determined by the exponent
(5 places in this example) i.e. 1.234 x 105 = 123 400.

If the exponent is negative the decimal point is moved to the left.

What is an IEEE 754 format floating-point number?

An IEEE 754 floating point number is the binary equivalent of the decimal floating-point
number shown above. The major difference being that the most significant bit of the

Appendix EngyVolt RV12

50

mantissa is always arranged to be 1 and is thus not needed in the representation of the
number. The process by which the most significant bit is arranged to be 1 is called
normalisation, the mantissa is thus referred to as a “normal mantissa”. During
normalisation the bits in the mantissa are shifted to the left whilst the exponent is
decremented until the most significant bit of the mantissa is one. In the special case where
the number is zero both mantissa and exponent are zero. The bits in an IEEE 754 format
have the following significance:

Data Hi Reg, Hi Byte. Data Hi Reg, Lo Byte. Data Lo Reg, Hi Byte. Data Lo Reg, Lo Byte.

SEEE
EEEE

EMMM
MMMM

MMMM
MMMM

MMMM
MMMM

Where:

S = represents the sign bit where 1 is negative and 0 is positive

E = is the 8-bit exponent with an offset of 127 i.e. an exponent of zero is represented by
127, an exponent of 1 by 128 etc.

M = the 23-bit normal mantissa. The 24th bit is always 1 and, therefore, is not stored.

Using the above format the floating point number 240.5 is represented as 43708000 hex:

Data Hi Reg, Hi Byte. Data Hi Reg, Lo Byte. Data Lo Reg, Hi Byte. Data Lo Reg, Lo Byte.

43 70 80 00

The following example demonstrates how to convert IEEE 754 floating-point numbers
from their hexadecimal form to decimal form. For this example, we will use the value for

240.5240.5 shown above.

The floating-point storage representation is not an intuitive format. To convert this
value to decimal, the bits should be separated as specified in the floating-point
number storage format table shown above.

For example:

Data Hi Reg, Hi Byte. Data Hi Reg, Lo Byte. Data Lo Reg, Hi Byte. Data Lo Reg, Lo Byte.

0100→0011 0111→0000 1000→0000 0000→0000

From this you can determine the following information.

• The sign bit is 0, indicating a positive number.

• • The exponent value is 10000110 binary or 134 decimal. Subtracting 127 from 134
leaves 7, which is the actual exponent.

• • The mantissa appears as the binary number 11100001000000000000000

There is an implied binary point at the left of the mantissa that is always preceded by a 1.
This bit is not stored in the hexadecimal representation of the floating-point number.
Adding 1 and the binary point to the beginning of the mantissa gives the following:

1.11100001000000000000000

Now, we adjust the mantissa for the exponent. A negative exponent moves the binary
point to the left. A positive exponent moves the binary point to the right. Because the
exponent is 7, the mantissa is adjusted as follows: 11110000.1000000000000000.

Finally, we have a binary floating-point number.

Binary bits that are to the left of the binary point represent the power of two
corresponding to their position. The result is the following decimal value:

.11110000 = (1 x 27) + (1 x 26) + (1 x 25) + (1 x 24) + (0 x 23)+ (0 x 22) + (0 x 21)+ (0 x

20) = 240

EngyVolt RV12 Appendix

51

Binary bits that are to the right of the binary point also represent a power of 2
corresponding to their position. As the digits are to the right of the binary point the
powers are negative. For example: .100… = (1 x 2-1) + (0 x 2-2)+ (0 x 2-3) + … = 0.5

Adding these two numbers together and making reference to the sign bit produces the
number +240.5.

For each floating point value requested two Modbus Protocol registers (four bytes) must be
requested. The received order and significance of these four bytes for EbgyVolt devices is
shown below:

Data Hi Reg, Hi Byte. Data Hi Reg, Lo Byte. Data Lo Reg, Hi Byte. Data Lo Reg, Lo Byte.

11.4.8 Modbus commands supported

All EngyVolt devices support the “Read Input Register” (3X registers), the “Read Holding
Register” (4X registers) and the “Pre-set Multiple Registers” (write 4X registers)
commands of the MODBUS Protocol RTU protocol. All values stored and returned are in
floating point format to IEEE 754 with the most significant register first.

Read input registers

MODBUS Protocol code 04 reads the contents of the 3X registers.

Example: The following query will request ‘Volts 1’ from an instrument with node address
1:

Field name Example (Hex)

Slave address 01

Function 04

Starting address High 00

Starting address Low 00

Number of points High 00

Number of points Low 02

Error check Low 71

Error check High CB

Data must be requested in register pairs i.e. the “Starting Address“ and the “Number
of Points” must be even numbers to request a floating point variable. If the “Starting
Address” or the “Number of points” is odd then the query will fall in the middle of a
floating point variable the product will return an error message.

The following response returns the contents of Volts 1 as 230.2.

But see also “Exception Response” later.

Field name Example (Hex)

Slave address 01

Function 04

Byte count 04

Data, High Reg, High Byte 43

Data, High Reg, Low Byte 66

Data, Low Reg, High Byte 33

Data, Low Reg, Low Byte 34

Appendix EngyVolt RV12

52

Field name Example (Hex)

Error check Low 1B

Erorr check High 38

11.4.9 Holding registers

Read holding registers

MODBUS Protocol code 03 reads the contents of the 4X registers.

Example: The following query will request the prevailing ‘Demand Time’:

Field name Example (Hex)

Slave address 01

Function 03

Starting address High 00

Starting address Low 00

Number of points High 00

Number of points Low 02

Error check Low C4

Error check High 0B

Data must be requested in register pairs i.e. the “Starting Address“ and the “Number
of Points” must be even numbers to request a floating point variable. If the “Starting
Address” or the “Number of points” is odd then the query will fall in the middle of a
floating point variable the product will return an error message.

The following response returns the contents of Demand Time as 1, But see also “Exception
Response” later.

Field name Example (Hex)

Slave address 01

Function 03

Byte count 04

Data, High Reg, High Byte 3F

Data, High Reg, Low Byte 80

Data, Low Reg, High Byte 00

Data, Low Reg, Low Byte 00

Error check Low F7

Error check High CF

Write holding registers

MODBUS Protocol code 10 (16 decimal) writes the contents of the 4X registers.

The following query will set the Demand Period to 60, which effectively resets the Demand
Time:

Field name Example (Hex)

Slave address 01

Function 10

EngyVolt RV12 Appendix

53

Field name Example (Hex)

Starting address High 00

Starting address Low 00

Number of registers High 00

Number of registers Low 02

Byte count 04

Data, High Reg, High Byte 00

Data, High Reg, Low Byte 00

Data, Low Reg, High Byte 00

Data, Low Reg, Low Byte 00

Error check Low F2

Error check High AF

Data must be written in register pairs i.e. the “Starting Address“ and the “Number of
Points” must be even numbers to write a floating point variable. If the “Starting
Address” or the “Number of points” is odd then the query will fall in the middle of a
floating point variable the product will return an error message.

In general only one floating point value can be written per query.

The following response indicates that the write has been successful. But see also
“Exception Response” later.

Field name Example (Hex)

Slave address 01

Function 10

Starting address High 00

Starting address Low 00

Number of registers High 00

Number of registers Low 02

Error check Low 41

Error check High C8

11.4.10 Exception response

If the slave in the “Write Holding Register” example above, did not support that function
then it would have replied with an Exception Response as shown below. The exception
function code is the original function code from the query with the MSB set i.e. it has had
80 hex logically OR'ed with it. The exception code indicates the reason for the exception.
The slave will not respond at all if there is an error with the parity or CRC of the query.
However, if the slave can not process the query then it will respond with an exception. In
this case a code 01, the requested function is not support by this slave.

Field name Example (Hex)

Slave address 01

Function 10 OR 80 = 90

Exception code 01

Error check Low 8D

Error check High C0

Appendix EngyVolt RV12

54

11.4.11 Exception codes

Table of exception codes

Exception code Modbus protocol name Description

01 Illegal function The function code is not supported by the product.

02 Illegal data address Attempt to access an invalid address or an attempt to

read or write part of a floating point value.

03 Illegal data value Attempt to set a floating point variable to an invalid

value.

05 Slave device failure An error occurred when the instrument attempted to

store an update to its configuration.

11.4.12 Diagnostics

MODBUS Protocol code 08 provides a number of diagnostic sub-functions. Only the
“Return Query Data” sub-function (sub-function 0) is supported on EngyVolt devices.

Example:

The following query will send a diagnostic “return query data” query with the data
elements set to Hex(AA) and Hex(55) and will expect these to be returned in the response:

Field name Example (Hex)

Slave address 01

Function 08

Sub-function High 00

Sub-function Low 00

Data byte 1 AA

Data byte 2 55

Error check Low 5E

Error check High 94

Exactly one register of data (two bytes) must be sent with this function.

The following response indicates the correct reply to the query, i.e. the same bytes as the
query.

Field name Example (Hex)

Slave address 01

Function 08

Sub-function High 00

Sub-function Low 00

Data byte 1 AA

Data byte 2 55

Error check Low 5E

Error check High 94

EngyVolt RV12 Appendix

55

11.5 RS485 Implementation of Johnson Controls Metasys

These notes briefly explain Metasys and EngyVolt device integration. Use these notes with
the Metasys Technical Manual, which provides information on installing and
commissioning Metasys N2 Vendor devices.

11.5.1 Application details

The EngyVolt multifunctional electrical energy meter is an N2 Vendor device that connects
directly with the Metasys N2 Bus. This implementation assigns key electrical parameters
to ADF points, each with override capability.

Components requirements:

• EngyVolt device with RS485 card and N2 port available.

• N2 bus cable

Metasys release requirements

• Metasys Software Release 12.04 or later

• NCM-361-8 or Metasys Extended Architecture NAE35,NAE45,NAE55

EngyVolt devices may be compatible with earlier releases of N2 software, but Johnson
Controls only supports integration issues on the above.

Support for Metasys integration

Please contact the nearest Jonson Controls Energy Efficency or Johnson Controls System &
Services representative. The address can be found on the Johnson Controls website.

Design considerations

When integrating the EngyVolt device equipment into a Metasys Network, keep the
following considerations in mind.

Make sure all EngyVolt device equipment is set up, started and running properly before
attempting to integrate with the Metasys Network.

A maximum of 32 devices can be connected to any one NCM N2 Bus segment, or up to
100 devices if repeaters are used.

From the instrument set-up screen, the Coms option must be set to N2, then the address
set to the required value. All port settings will then be set automatically, see below.

Device address 1 to 255

Port set up:

Baud rate

1)

9600

Duplex Half

Word length 8

Stop bits

1)

1

Parity

1)

no

Interface RS485

1) The user has to make sure that the values given are set up in the EngyVolt device in order to ensure
compatibility with the N2 protocol network.

Appendix EngyVolt RV12

56

11.5.2 EngyVolt Metasys N2 point mapping table

Name Description Unit ADF point

V1 Phase 1 line to neutral volts V 1

V2 Phase 2 line to neutral volts V 2

V3 Phase 3 line to neutral volts V 3

A1 Phase 1 current A 4

A2 Phase 2 current A 5

A3 Phase 3 current A 6

KP1 Phase 1 power kW 7

KP2 Phase 2 power kW 8

KP3 Phase 3 power kW 9

KVA1 Phase 1 volt amps kVA 10

KVA2 Phase 2 volt amps kVA 11

KVA3 Phase 3 volt amps kVA 12

KVAR1 Phase 1 volt amps reactive kvar 13

KVAR2 Phase 2 volt amps reactive kvar 14

KVAR3 Phase 3 volt amps reactive kvar 15

PF1 Phase 1 power factor - 16

PF2 Phase 2 power factor - 17

PF3 Phase 3 power factor - 18

PA1 Phase 1 phase angle Degrees 19

PA2 Phase 2 phase angle Degrees 20

PA3 Phase 3 phase angle Degrees 21

AN Neutral current A 22

V12 Line voltage P1-P2 V 23

V23 Line voltage P2-P3 V 24

V31 Line voltage P3-P1 V 25

VLNAVG Average line to neutral volts V 26

AAVG Average current A 27

ASUM Total system current THD V3 A 28

VLLAVG Average line voltage V 29

KPSUM Total system power kW 30

KVASUM Total system volt amps kVA 31

KVARSUM Total system Var kvar 32

PFTOT Total system power factor - 33

PATOT Total system phase angle Degrees 34

FREQ Frequency Hz 35

LO_EGY_IMP_P
OW*

Imported Wh, lower value 0.1 kWh 36

HI_EGY_IMP_P
OW*

Imported Wh, higher value 100 MWh 37

LO_EGY_EXP_P
OW*

Exported Wh, lower value 0.1 kWh 38

* The values represented refer to the prefix "k" for energy values. For prefix "M" they are larger by factor 1000.

EngyVolt RV12 Appendix

57

Name Description Unit ADF point

HI_EGY_EXP_P
OW*

Exported Wh, higher value 100 MWh 39

LO_EGY_IMP_V
AR*

Imported Varh, lower value 0.1 kvarh 40

HI_EGY_IMP_V
AR*

Imported Varh, higher value 100 Mvarh 41

LO_EGY_EXP_V
AR*

Exported Varh, lower value 0.1 kvarh 42

HI_EGY_EXP_V
AR*

Exported Varh, higher value 100 Mvarh 43

LO_EGY_VA* VAh, lower value 0.1 kVAh 44

HI_EGY_VA* VAh, higher value 100 MVAh 45

LO_EGY_AMP* Ah, lower value 0.1 Ah 46

HI_EGY_AMP* Ah, higher value 100 kAh 47

KPSUM_DMD Total system power demand kW 48

KPSUM_MAX_DMDMaximum total system power demand kW 49

KVASUM_DMD Maximum total system power demand kVA 50

KVASUM_MAX
_DMD

Maximum total system VA demand kVA 51

A1_DMD Phase 1 current demand A 52

A1_MAX_DMD Maximum phase 1 current demand A 53

A2_DMD Phase 2 current demand A 54

A2_MAX_DMD Maximum phase 2 current demand A 55

A3_DMD Phase 3 current demand A 56

A3_MAX_DMD Maximum phase 1 current demand A 57

AN_DMD Neutral current demand A 58

AN_MAX_DMD Maximum neutral current demand A 59

V1_THD Line 1 to neutral volts THD % 60

V2_THD Line 2 to neutral volts THD % 61

V3_THD Line 3 to neutral volts THD % 62

VLNAVG_THD Line to neutral volts THD average % 63

V12_THD Line 1 to line 2 volts THD % 64

V23_THD Line 2 to line 3 volts THD % 65

V31_THD Line 3 to line 1 volts THD % 66

VLLAVG_THD Line to line volts THD average % 67

A1_THD Phase 1 Current THD % 68

A2_THD Phase 2 Current THD % 69

A3_THD Phase 3 Current THD % 70

AAVG_THD Phase Current THD average % 71

RESET Reset - 72

* The values represented refer to the prefix "k" for energy values. For prefix "M" they are larger by factor 1000.

Appendix EngyVolt RV12

58

In order to generate a reset, write the following values to the register "RESET".

Reset Write

All energy values (electrical energy values) 1011

All demand average / maximum values 1012

Demand time base 1013

ADF points are one-based in the JCI compliance test software but zero-based on the
network.

EngyVolt RV12 Index

59

Index

0 … 9

3-phase, 3-wire .............................11

3-phase, 4-wire .............................13

A

Addr .....................................22

B

bAUd .................................... 22

C

Calling up the Setup menu .................. 20, 20

CHNG PASS ................................20

COMS .................................... 21

Configuration example

Current transformer primary value ............ 19

CT .......................................21

D

Device settings ............................. 20

Changing the password .................... 20

Communication settings ................... 21

Current transformer primary value ............ 21

Energy values ............................23

Integration time for recording maximum values .. 21

Measurement limit ....................... 23

Protocol ................................ 22

Pulse length .............................23

Pulse rate ...............................23

Relay output .............................23

Reset .................................. 21

Self-test ................................24

Setting the baud rate ...................... 22

Setting the device address ...................22

Setting the floating point ................... 23

Setting the parity .........................22

Software version ......................... 24

Stop bits ............................... 22

System configuration ......................21

dIT ...................................... 21

Drag indicator .............................. 34

E

Electrical connection

3-phase, 3-wire .......................... 11

3-phase, 4-wire .......................... 13

Single-phase, 2-wire .......................11

Energy resolution ........................... 34

Entering numbers ........................... 17

L

Lmt ..................................... 23

M

Maximum demand .......................... 34

Maximum indicator function ................... 21

Measuring device

Return ................................. 26

Metasys

Design considerations ......................55

Metasys N2

Application details ........................ 55

Point mapping table ....................... 56

Requirements ............................55

Modbus

A and B terminals ........................ 42

Commands ..............................51

Connecting the instruments ................. 42

Data coding ............................. 36

Data format ............................. 44

Diagnostics ............................. 54

Error checking methods .................... 48

Exception codes .......................... 54

Exception response .....................46, 53

Function codes ........................... 49

Half duplex ............................. 41

Holding registers ...................... 39, 52

IEEE floating point format .................. 49

Input registers ........................... 37

Message timing .......................... 47

Modes ................................. 46

Password ............................... 41

Protocol overview .........................35

Query ..................................44

Register order ........................... 40

Response ............................... 45

Serial data transmission .................... 47

Troubleshooting ..........................43

N

NRGY .................................... 23

O

Operational safety ............................4

Ordr ..................................... 23

Outputs

Pulse output .............................14

RS485 ................................. 13

P

PARI .....................................22

Phase to Phase voltages .......................34

Power factor ............................... 34

PROT .................................... 22

PULS .....................................23

Pulse output ............................... 14

R

RATE .................................... 23

Reactive and Apparent Power .................. 34

Return ................................... 26

RLY ......................................23

RS485 ....................................13

RSET .....................................21

Index EngyVolt RV12

60

S

Single-phase, 2-wire ......................... 11

SOFT .....................................24

Staff

Requirements .............................4

STOP .................................... 22

SYS ...................................... 21

T

TEST .....................................24

Testing the phase sequence .................... 35

THD ..................................... 35

Total harmonic distortion – THD ................ 35

W

Workplace safety ............................ 4

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