Danfoss VLT 2800, VLT 6000, VLT 8000 Operating guide

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Operating Instructions

Modbus RTU

VLT® 2800

VLT® 6000

VLT® 8000

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■ Contents

Overview

Introduction ............................................................................................................ 6

About This Manual ................................................................................................. 6

Assumptions .......................................................................................................... 6

What You Should Already Know ............................................................................. 6

Modbus RTU Overview .......................................................................................... 6

VLT 2800, VLT 6000 and VLT 8000 with Modbus RTU ........................................... 7

............................................................................................................. 6

Installation and Setup .................................................................................. 8

Network Connection ............................................................................................. 8

Hardware Setup VLT 2800 ..................................................................................... 9

Hardware Setup VLT 6000 and VLT 8000 ............................................................... 9

EMC Precautions ................................................................................................... 9

Modbus RTU Programming ....................................................................... 10

VLT 2800 Parameter Settings for Modbus Communication ..................................... 10

VLT 6000 Parameter Settings for Modbus Communication ..................................... 12

Installation and Set-up VLT 8000 ............................................................................ 13

VLT 8000 Parameter Settings for Modbus Communication ..................................... 13

Network Configuration ................................................................................. 14

Remote Terminal Unit ............................................................................................. 14

Modbus RTU Message Framing Structure .............................................................. 14

Parameter Handling ....................................................................................... 16

Parameter Handling ................................................................................................ 16

Storage of Data ...................................................................................................... 16

Process Data ......................................................................................................... 20

Status Coil Maps .................................................................................................... 20

Control Word Bit Descriptions for VLT 2800 ............................................................ 20

Status Word Bit Description for VLT 2800 ............................................................... 21

Control Word Bit Descriptions VLT 6000 / VLT 8000 ............................................... 23

Status Word Bit Descriptions VLT 6000 / VLT 8000 ................................................ 25

Serial communication reference .............................................................................. 26

Present output frequency ....................................................................................... 26

Supported Modbus RTU Function C odes ......................................... 28

Exception Codes ............................................................................................. 31

Exception Code Tables .......................................................................................... 31

Appendix A - Examples ............................................................................... 32

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Software Version VLT 2800, VLT 6000 and VLT 8000

VLT 2800 Series

Operating instructions Software version: 2.8x

These operating instructions can be used for all VLT 2800 Series frequency converters with software version 2.8x. The software version number can be seen from parameter 640 Software version no.

195NA009.17

VLT 6000 HVAC

Operating Instructions Software version: 3.0x

These Operating Instructions can be used for all VLT 6000 HVAC frequency converters with software version 3.0x. The software version number can be seen from parameter

624.

175ZA691.14

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

VLT 8000 AQUA

Operating Instructions Software version: 1.5x

176FA145.13

RTU

These Operating Instructions can be used for all VLT 8000 AQUA frequency converters with software version 1.5x. The software version number can be seen from parameter 624

Software version no.

■High Voltage Warning

Rotating shafts and electrical equipment can be hazardous. Therefore, it is stron

recommended that all electrical work conform to National Electrical Code (NEC) and all local regulations. Installation, s should be performed only by qualified personnel.

Motor control equipment and electronic controls are connected to hazardous line voltages. When servicing

■Warnings Against Unintended Start

1. While t

2. During programming of parameters, the motor

he frequency converter is connected to the AC line, the motor can be brought to a stop by means of external switch closures,

rial bus commands or references. If personal

se safety considerations make it necessary to ensure that no unintended start occurs, these stops are not sufficient.

may start. Be certain that no one is in the

tart-up and maintenance

gly

frequency converters and electronic controls, there will be exposed components at or above line pote Extreme care should be taken to protect against shock. Stand on an insulating pad and make it a habit to use only one hand when checking component work with another person in case of an emergency. Disconnect power whenever possible to check controls or to perform maintenance. Be properly grounded. Wear safety glasses whenever working on electric control or rotating equipment.

area of the motor or frequency converter driven

pment when changing parameters

equi

3. A motor that has been stopped may start unexpectedly if faults occur in the electronics

the frequency converter, or if an overload, a

of fault in the supply AC line or a fault in the motor connection or other fault clears.

f the "Local/Hand" key is activated, the motor

4.I can only be brought to a stop by means of the "Stop/Off" key or an external safety interlock.

sure equipment is

ntial.

s. Always

Safety - Modbus

■Electrostatic discharge (ESD)

Electronic components are sensitive to electrostatic discharge (ESD). ESD can

reduce performance or destroy sensitive electronic components. Follow proper ESD procedures during installation or servicing to prevent damage.

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

VLT 2800

It can be extremely dangerous to touch the electrical parts even when the mains

supply has been disconnected.

Also ensure that other voltage inputs are disconnected from load sharing through the

DC bus.

Wait at least 4 minutes after the input power has been removed before servicing the

drive.

195NA139.10

VLT 6000 HVAC

Warning:

Touching the electrical parts may be fatal - even after the equipment has been disconnected from mains.

Using VLT 6002 - 6005, 200-240 V: Wait at least 4 minutes Using VLT 6006 - 6062, 200-240 V: Wait at least 15 minutes Using VLT 6002 - 6005, 380-460 V: Wait at least 4 minutes Using VLT 6006 - 6072, 380-460 V: Wait at least 15 minutes Using VLT 6102 - 6352, 380-460 V: Wait at least 20 minutes Using VLT 6400 - 6550, 380-460 V: Wait at least 15 minutes Using VLT 6002 - 6006, 525-600 V: Wait at least 4 minutes Using VLT 6008 - 6027, 525-600 V: Wait at least 15 minutes

Using VLT 6032 - 6275, 525-600 V: Wait at least 30 minutes

175HA490.11

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

VLT 8000 AQUA

Touching the electrical parts may be fatal - even after the equipment has been disconnected from line.

Warning:

VLT 8006-8062, 200-240 V: wait at least 15 minutes VLT 8006-8072, 380-480 V: wait at least 15 minutes VLT 8102-8352, 380-480 V: wait at least 20 minutes VLT 8450-8600, 380-480 V: wait at least 15 minutes VLT 8002-8006, 525-600 V: wait at least 4 minutes VLT 8008-8027, 525-600 V: wait at least 15 minutes VLT 8032-8300, 525-600 V: wait at least 30 minutes

176FA159.12

RTU

Safety - Modbus

MG.10.S2.02 - VLT is a registered Danfoss trademark

■Overview

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Introduction

These operating instructions provide comprehensive instructions on the installation and set up of the

Modbus RTU for VLT

and VLT

8000 AQUA Frequency Converter to

2800, VLT®6000 HVAC

communicate over a Modbus network.

For specific information on installation and operation

2800 6000

of the frequency converter, refer to the VLT Operating Instructions, MG.28.AX.YY / VLT HVAC Operating Instructions, MG.61.AX.YY /

8000 Operating Instructions, MG.80.AX.YY.

VLT

■About This Manual

These operating instructions are intended to be used for both instruction and reference. It only briefly touches on the basics of the Modbus protocol whenever necessary to gain an understanding of the Modbus RTU.

These operating instructions are also intended to serve as a guideline when you specify and optimise your communication system. Even if you are an experienced Modbus programmer, it is suggested that you read these operating instructions in its entirety before you start programming since impor information can be found in all sections.

■Assumptions

These operating instructions assume that you have a controller that supports the interfaces

in this document and that all the requirements stipulated in the controller, as well as the frequency converter, are strictly observed, along with all l

imitations therein.

tant

other devices, and how errors will be detected and reported. It establishes a common format for the layout and contents of message fields.

During communications on a Modbus RTU network, the protocol determines how each controller will know its device address, recognise a message addressed to it, determine the kind of action to be taken, and extract any data or other information contained in the message. If a reply is required, the controller will construct the reply message and send it.

Controllers communicate using a master-slave technique in which only one device (the master) can initiate transactions (called queries). The other devices (slaves) respond by supplying the requested data to the master, or by taking the action requested in the query.

The master can address individual slaves, or can initiate a broadcast message to all slaves. Slaves return a message (called a response) to queries that are addressed to them individually. Responses are not returned to broadcast queries from the master.

The Modbus RTU protocol establishes the format

for the master’s query by placing into it the device

(or broadcast) address, a function code defi

ning

the requested action, any data to be sent, and an

error-checking field. The slave’s response message

is also constructed using Modbus pro

tocol. It contains fields confirming the action taken, any data to be returned, and an error-checking field. If an error occurred in receipt of the m

essage, or if the slave is unable to perform the requested action, the slave will construct an error message and send it in response or a time-out wi

ll occur.

■What You Should Already Know

The Modbus RTU is designed to communicate with any controller that supports the interfaces defined in this document. It is assumed that yo

u have full knowledge

of the capabilities and limitations of the controller.

■Modbus RTU Overview

Modbus RTU (Remote Terminal Unit) protocol defines a message structure that co

ntrollers will recognise and use, regardless of the type of physical networks over which they communicate. It describes the process a controller use

s to request access to another

device, how it will respond to requests from the

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■VLT 2800, VLT 6000 and VLT 8000 with Modbus RTU

The frequency converter communicates in Modbus RTU format over an EIA-485 (formerly RS-485) network. Modbus RTU allows access to the frequency

converter’s Control Word and Bus Reference.

The Control Word allows the Modbus master to control several important functions of the frequency converter:

• Start

• Stop the frequency converter in several ways:

Coast stop Quick stop DC Brake stop Normal (ramp) stop

• Reset after a fault trip

• Run at a variety of preset speeds

• Runinreverse

• Change the active setup

• Control the frequency converter’s two built-in relays

The Bus Reference is commonly used for speed control.

It is also possible to access the parameters, read their values, and, where possible, write values to them. This permits a range of control possibilities,

including controlling the frequency converter’ssetpoint

when its internal PID controller is used.

Overview

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Installation and Setup

Modbus RTU is a transmission protocol developed for process control systems. The Modbus standard does not specify the physical interface for the protocol i.e. a number of different interfaces can be chosen. The Modbus RTU protocol is based on the build-in RS-485 (EIA-485) interface. RS-485 is a two-wire bus-interface that allows multi-drop network topology i.e. nodes can be connected as a bus, or via drop cables from a common trunk line. A total number of 32 nodes can be connected to one Modbus RTU network segment, and a total of 247 nodes in a network are supported. Network segments are divided with repeaters. Please note that each repeater counts for a node

in each segment it’sinstalled.

Every node connected to the same network must have an unique nodes address, across all segments.

Every segment must be terminated in both ends, either with the termination switches (switch 2 &

3) of the VLT 6000 / VLT 8000 or with a biased termination resistor network.

It is very important to have a low impedance ground connection of the screen, also at high frequencies. This can be obtained by connecting a large surface of the screen to ground, for example by means of a cable clamp or a conductive cable gland. Particularly in installation where there is long cable lengths, it can be necessary to apply potential equalizing cables to ensure same ground potential throughout the network. To prevent impedance mismatch, always use cable of same type across the entire network. When connecting a motor to the frequency converter, make sure always to use screened motor cable.

Address range:

1-247

Baud Rate:

300 - 9600 bps

Cable:

Screened twisted pair (STP) Impedance: 120 Ohm

For bus-cabling always use cable of screened twisted pair type (STP), and make sure to follow good common installation practice. Make sure the screen of the Modbus RTU cable must always be connected to ground at all nodes.

■Network Connection

Connect the frequency converter to the Modbus RTU in accordance with the following procedure (see Figure 1).

1. Connect signal wires to terminal 68 (P+) and

terminal 69 (N-) on main control board of the frequency converter.

2. The shield of the cable must be connected

to the cable clamps.

NB!:

It is recommended to use shielded, twisted-pair cables to reduce noise between conductors.

Cable length:

Max. 1200 m (including drop lines) Max. 500 m station-to-station

Figure 1 Network Terminal Connection

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Hardware Setup VLT 2800

The VLT 2800 control card does not have build-in termination network for RS 485. To terminate with the

■Hardware Setup VLT 6000 and VLT 8000

A terminator dip switch on the main control board of the frequency converter is used to terminate the Modbus RTU bus. The switch positions shown in Figure 2 demonstrate the factory setting. Table 1 lists the switch functions and settings required for Modbus RTU operation.

correct impedance in the network the following resistors shouldbeappliedatthefirstandthelaststation.

Figure 2 Terminator Switch Factory Setting

NB!:

Factory setting for DIP Switch is on.

Table 1 Terminator Switch Functions and Modbus RTU Switch Setting

Switches 2 & 3 Used for terminating an RS-485 interface. On first and last devices in a multiple device

network, or on the only device in a single device network, switches 2 and 3 must be ON. On all other devices in a multiple device network, 2 and 3 must be OFF.

NB!:

Terminator switch positions must be set correctly in accordance with Table 1 for proper Modbus RTU serial communication.

■EMC Precautions

The following EMC precautions are recommended in order to achieve interference-free operation of the Modbus RTU network.

NB!:

Relevant national and local regulations, for example regarding protective earth connection, must be observed.

The Modbus RTU communication cable must be kept away from motor and brake resistor cables to avoid coupling of high frequency noise from one cable to the other. Normally a distance of 200 mm (8 inches) is sufficient, but it is generally recommended to keep the greatest possible distance between the cables, especially where cables run in parallel over long distances. If the Modbus RTU cable has to cross a motor and brake resistor cable they must cross each other at an angle of 90 degrees.

Setup

Installation and

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■VLT 2800 Parameter Settings for Modbus

Communication

Using the Modbus RTU Protocol requires setting of the below listed parameters.

NB!:

Please make sure that par. 512 Te le gr am Profile is set to FC PROFILE.

See the VLT 2800 Operating Instructions MG.28.AX.YY for details on selecting and changing parameter values, if necessary.

500 Address

(BUS ADDRESS)

Value:

Parameter 500 Protocol = FC protocol [0]

0 - 247

Parameter 500 Protocol = Metasys N2 [1]

1 - 255

Parameter 500 Protocol = MODBUS RTU [3]

1 - 247

Function:

This parameter allows the allocation of an address to each frequency converter in a serial communication network.

Description of choice:

The individual frequency converter must be allocated a unique address. If the number of units connected (frequency converters + master) is higher than 31, a repeater must be used. Parameter 500 Address cannot be selected via the serial communication, but must be preset via the control unit.

✭ 1

Description of choice:

The frequency converter’s transmission speed

must be set at a value corresponding to the transmission speed of the master. Parameter 501 Baudrate cannot be selected via the serial port, but must be preset via the operating unit.

561 Protocol

(PROTOCOL)

Value:

✭FC protocol (FC PROTOCOL)

Metasys N2 (METASYS N2) MODBUS RTU (MODBUS RTU)

Function:

There is a choice of three different protocols.

Description of choice:

Select the required control word protocol.

570 Modbus parity and message framing

(M.BUS PAR./FRAME)

Value:

(EVEN/1 STOPBIT) (ODD/1 STOPBIT)

✭(NO PARITY/1 STOPBIT)

(NO PARITY/2 STOPBIT)

Function:

This parameter sets up the drive’sModbusRTU

interface to communicate properly with the master controller. The parity (EVEN, ODD, or NO PARITY) must be set to match the setting of the master controller.

[1] [2] [3]

[0] [1] [2] [3]

Description of choice:

501 Baudrate

(BAUDRATE)

Value:

300 Baud (300 BAUD) 600 Baud (600 BAUD) 1200 Baud (1200 BAUD) 2400 Baud (2400 BAUD) 4800 Baud (4800 BAUD)

✭9600 Baud (9600 BAUD)

Function:

This parameter is for programming the speed at which data is transmitted via the serial port. Baud rate is defined as the number of bits transmitted per second.

✭ = factory setting. () = display text [] = value for use in communication via serial communication port

[0] [1] [2] [3] [4] [5]

Select the parity that matches the setting for the Modbus master controller. Even or odd parity is sometimes used to allow a transmitted word to be checked for errors. Because Modbus RTU uses the more efficient CRC (Cyclic Redundancy Check) method of checking for errors, parity checking is seldom used in Modbus RTU networks.

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

571 Modbus communications timeout

(M.BUS COM.TIME.)

Value:

10 ms - 2000 ms

Function:

This parameter determines the maximum amount

of time that the drive’sModbusRTUwillwait

between characters that are sent by the master controller. When this amount of time expires, the

drive’s Modbus RTU interface will assume that it

has received the entire message.

Description of choice:

Generally, the value of 100 ms is sufficient for Modbus RTU networks, although some Modbus RTU networks may operate on a time-out value as short as 35 ms.

If this value is set too short, the drive’sModbusRTU

interface may miss a part of the message. Since the CRC check will not be valid, the drive will ignore the message. The resulting retransmissions of messages will slow communications on the network. If this value is set too long, the drive will wait longer than necessary to determine that the message is

completed. This will delay the drive’s response to the

message and possibly cause the master controller to time out. The resulting retransmissions of messages will slow communications on the network.

✭ 100 ms

✭ = factory setting. () = display text [] = value for use in communication via serial communication port

MG.10.S2.02 - VLT is a registered Danfoss trademark

Modbus RTU

Programming

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■VLT 6000 Parameter Settings for Modbus

Communication

Using the Modbus RTU Protocol requires setting of the below listed parameters. See the VLT 6000 Operating Instructions MG.61.AX.YY for details on selecting and changing parameter values, if necessary.

500 Protocol

(PROTOCOL)

Value:

✭FC protocol (FC PROTOCOL)

Metasys N2 (METASYS N2) Landis/Staefa Apogee FLN (LS FLN) Modbus RTU (MODBUS RTU)

Function:

There is a choice of four different protocols.

Description of choice:

Select the required control word protocol.

[0] [1] [2] [3]

570 Modbus parity and message framing

(M.BUS PAR./FRAME)

Value:

(EVEN/1 STOPBIT) (ODD/1 STOPBIT)

✭(NO PARITY/1 STOPBIT)

(NO PARITY/2 STOPBIT)

Function:

This parameter sets up the drive’sModbusRTU

interface to communicate properly with the master controller. The parity (EVEN, ODD, or NO PARITY) must be set to match the setting of the master controller.

Description of choice:

[0] [1] [2] [3]

501 Address

(ADDRESS)

Value:

Parameter 500 Protocol = FC protocol [0]

0 - 126

Parameter 500 Protocol = Metasys N2 [1]

1 - 255

Parameter 500 Protocol = LS FLN [2]

0-98

Parameter 500 Protocol = MODBUS RTU [3]

1 - 247

Function:

In this parameter it is possible to allocate an address in a serial communication network to each frequency converter.

Description of choice:

The individual frequency converter must be given a unique address. If the number of units connected (frequency converters + master) exceeds 31, an amplifier (repeater) must be used. Parameter 501 Address cannot be chosen via serial communication, but must be set via the LCP control unit.

✭ 1

571 Modbus communications timeout

(M.BUS COM.TIME.)

Value:

10 ms - 2000 ms

Function:

This parameter determines the maximum amount

of time that the drive’sModbusRTUwillwait

between characters that are sent by the master controller. When this amount of time expires, the

drive’s Modbus RTU interface will assume that it

has received the entire message.

Description of choice:

Generally, the value of 100 ms is sufficient for Modbus RTU networks, although some Modbus RTU networks may operate on a time-out value as short as 35 ms.

If this value is set too short, the drive’sModbusRTU

completed. This will delay the drive’s response to the

message and possibly cause the master controller to time out. The resulting retransmissions of messages will slow communications on the network.

✭ 100 ms

✭ = factory setting. () = display text [] = value for use in communication via serial communication port

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■VLT 8000 Parameter Settings for Modbus

Communication

Using the Modbus RTU Protocol requires setting of the below listed parameters. See the VLT 8000 Operating Instructions MG.80.AX.YY for details on selecting and changing parameter values, if necessary.

500 Protocol

(PROTOCOL)

Value:

✭FC protocol (FC PROTOCOL)

Modbus RTU (MODBUS RTU)

Function:

There is a choice of two different protocols.

Description of choice:

Select the required control word protocol.

501 Address

(ADDRESS)

Value:

Parameter 500 Protocol = FC protocol [0]

0 - 126

Parameter 500 Protocol = MODBUS RTU [1]

1 - 247

Function:

In this parameter it is possible to allocate an address in a serial communication network to each frequency converter.

Description of choice:

[0] [1]

✭ 1

Function:

This parameter sets up the drive’sModbusRTU

interface to communicate properly with the master controller. The parity (EVEN, ODD, or NO PARITY) must be set to match the setting of the master controller.

Description of choice:

571 Modbus communications timeout

(M.BUS COM.TIME.)

Value:

10 ms - 2000 ms

Function:

This parameter determines the maximum amount

of time that the drive’sModbusRTUwillwait

between characters that are sent by the master controller. When this amount of time expires, the

drive’s Modbus RTU interface will assume that it

has received the entire message.

Description of choice:

Generally, the value of 100 ms is sufficient for Modbus RTU networks, although some Modbus RTU networks may operate on a time-out value as short as 35 ms.

If this value is set too short, the drive’sModbusRTU

completed. This will delay the drive’sresponse

message and possibly cause the master controller to time out. The resulting retransmissions of messages will slow communications on the network.

✭ 100 ms

to the

Modbus RTU

Programming

570 Modbus parity and message framing

(M.BUS PAR./FRAME)

Value:

(EVEN/1 STOPBIT) (ODD/1 STOPBIT)

✭(NO PARITY/1 STOPBIT)

(NO PARITY/2 STOPBIT)

✭ = factory setting. () = display text [] = value for use in communication via serial communication port

MG.10.S2.02 - VLT is a registered Danfoss trademark

[0] [1] [2] [3]

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Network Configuration

■Remote Terminal Unit

The controllers are setup to communicate on the Modbus network using RTU (Remote Terminal Unit) mode, with each 8-bit byte in a message contains two 4-bit hexadecimal characters. The format for each byte is shown below.

Coding System: 8-bit binary, hexadecimal 0-9, A-F

Two hexadecimal characters contained in

each 8-bit field of the message

Bits Per Byte: 1startbit

8 data bits, least significant bit sent first

1 bit for even/odd parity; no bit for no parity

1 stop bit if parity is used; 2 bits if no parity

Error Check Field: Cyclical Redundancy Check (CRC)

Start bit Data bit Stop/

■Modbus RTU Message Framing Structure

A Modbus RTU message is placed by the transmitting device into a frame with a known beginning and ending point. This allows receiving devices to begin

monitor the network bus continuously, including ‘silent’

intervals. When the first field (the address field) is received, each frequency converter or device decodes

it to determine whether it is the addressed device. at the start of the message, read the address portion, determine which device is addressed (or all devices, if the message is broadcast), and to know when the message is completed. Partial messages are detected and errors set as a result.

Modbus RTU messages addressed to zero are

broadcast messages. No response is permitted

on broadcast messages.

A typical message frame is shown below.

The allowable characters transmitted for all fields are hexadecimal 00 to FF. The frequency converter

Start Address Function Data CRC Check End

T1-T2-T3-T4 8Bits 8Bits nx8bits 16 Bits T1-T2-T3-T4

Typical Modbus RTU Message Structure

Stop

parity

■Start/Stop Field

Messages start with a silent interval of at least 3.5 character times. This is implemented as a multiple of character times at the selected network baud rate (shown as Start T1-T2-T3-T4). The first field then transmitted is the device address. Following the last transmitted character, a similar interval of at least 3.5 character times marks the end of the message. A new message can begin after this interval.

Theentiremessageframemustbetransmittedasa continuous stream. If a silent interval of more than

1.5 character times occurs before completion of the frame, the receiving device flushes the incomplete

message and assumes that the next byte will be

the address field of a new message.

Similarly, if a new message begins earlier that 3.5

character times following a previous message, the

receiving device will consider it a continuation of the

previous message. This will cause a time-out (no

response from the slave), since the value in the final

CRC field is not valid for the combined messages.

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Address Field

The address field of a message frame contains 8 bits. Valid slave device addresses are in the range of 0 – 247 decimal. The individual slave devices are assigned addresses in the range of 1 – 247. (0 is reserved for broadcast mode, which all slaves recognize.) A master addresses a slave by placing the slave address in the address field of the message. When the slave sends its response,itplacesitsownaddressinthisaddressfield to let the master know which slave is responding.

■Function Field

The function field of a message frame contains 8 bits. Valid codes are in the range of 1-FF. (See section Modbus RTU Function Codes.) When a message is sent from a master to a slave device, the function code field tells the slave what kind of action to perform.

When the slave responds to the master, it uses the function code field to indicate either a normal (error-free) response, or that some kind of error occurred (called an exception response). For a normal response, the slave simply echoes the original function code. For an exception response, the slave returns a code that is equivalent to the original function code with its most-significant bit set to a logic 1. In addition, the slave places a unique code into the data field oftheresponsemessage. Thistellsthemaster what kind of error occurred, or the reason for the exception. See the chapter Exception Codes in these operating instructions for definitions.

appends the CRC as the last field in the message. The

receiving device recalculates a CRC during receipt of

the message and compares the calculated value to

the actual value received in the CRC field. If the two

values are not equal, a bus time-out results.

The error checking field contains a 16-bit binary

value implemented as two 8-bit bytes. When this is

done, the low-order byte of the field is appended first,

followed by the high-order byte. The CRC high-order

byteisthelastbytesentinthemessage.

■Coil/Register Addressing

All data addresses in Modbus messages are referenced

to zero. The first occurrence of a data item is

addressed as item number zero. For example:

The coil known as ‘coil 1’ in a programmable controller

is addressed as coil 0000 in the data address

field of a Modbus message. Coil 127 decimal is

addressed as coil 007E

(126 decimal).

HEX

Holding register 40001 is addressed as register

0000 in the data address field of the message.

The function code field already specifies a ‘holding

is implicit. Holding register 40108 is addressed

as register 006B

(107 decimal).

HEX

■Data Field

The data field is constructed using sets of two hexadecimal digits, in the range of 00 to FF hexadecimal. These are made from one RTU character. The data field of messages sent from a master to slave device contains additional information which the slave must use to take the action defined by the function code. This can include items like coil or register addresses, the quantity of items to be handled, and the count of actual data bytes in the field.

■CRC Check Field

Messages include an error-checking field that is based on a cyclical redundancy check (CRC) method. The CRC field checks the contents of the entire message. It is applied regardless of any parity check method used for the individual characters of the message. The CRC value is calculated by the transmitting device, which

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Network

Configuration

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Parameter Handling

PNU (Parameter Number) is translated from the register address contained in the Modbus read/write message. The parameter number is translated to Modbus as (10 x parameter number)

DECIMAL

■Storage of Data

Coil 65 decimal determines whether data written to the frequency converter are stored in EEPROM and RAM (coil 65 = 1) or just RAM (coil 65 = 0).

■IND

Array index is set in Holding Register 9 and used when accessing array parameters in the frequency converter such as parameter 606-617 (Logs).

■Text Blocks

Parameters stored as text strings are accessed in the same way as the other parameters. The maximum text block size is 20 characters. If a read request for a parameter is for more characters than the parameter stores, the response is space filled. If the read request for a parameter is for less characters than the parameter stores, the response is truncated.

Index Factor

74 3.6

2 100.0 1 10.0 0 1.0

-1 0.1

-2 0.01

-3 0.001

-4 0.0001

■Parameter Values

Standard Data Types

Standard data types are int16, int32, uin

t8, uint16 and uint32. They are stored as 4x registers (40001 – 4FFFF). The parameters are read using function 03 "Read Holding Registers." Par function 6 bits), and function 10

"Preset Single Register" for 1 register (16

HEX

2registers(32bits). Vali

ameters are written using

"Preset Multiple Registers" for

d sizes to read are 1 register

(16 bits) and through 10 registers (20 characters).

Nonstandard D ata Types

Nonstandard data types are text strings and are stored as 4x registers (4000 read using function 03 and written using function 10 Registers." Va

1 – 4FFFF). The parameters are

"Read Holding Registers"

HEX

"Preset Multiple

HEX

lid sizes to read are 1 register (2

characters) through 10 registers (20 characters).

HEX

■PCD1/PCD

PCD contains the process word block. The parameter value block consists of 2 words (4 bytes). The process word block is divided into two blocks of 16 bits and is stored in Modbus as status coils. The map

ping

of the PCD is shown in the table below.

■Conversion Factor

The different attributes for each parameter can be seen in the section on factory settings. Si

nce a parameter value can only be transferred as a whole number, a conversion factor must be used to transfer decimals.

Parameter 201: Minimum Frequency,conversion factor 0.1. If parameter 201 is

to be set to 10 Hz, a value of 100 must be transferred, since a conversion factor of 0.1 means that the transferred value will be multiplied by 0

.1. A value of 100 will,

therefore, be understood as 10.0.

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■Register Maps VLT 2800

Note: the Holding Register number shown in the following table must be transmitted as ("shown value-1") in MODBUS telegrams (e.g. Holding Register 4:00001 is transmitted as address 0 in MODBUS telegrams).

Holding Register

Description

(decimal)

00001-00008 Reserved 00009 Array index (1-255) 00010 Parameter 001, Language

↓ ↓

00250 Parameter 025, Quick Menu Setup 00260-00999 Reserved 01000 Parameter 100, Configuration

↓ ↓

01460 Parameter 146, Reset Voltage Vector 01470-1999 Reserved 02000 Parameter 200, Output Frequency Range

↓ ↓

02310 Parameter 231, Frequency Bypass 2 02320-02999 Reserved 03020 Parameter 302, Digital Input, Terminal 18

↓ ↓

03490 Parameter 349, Speed Compensation Delay 03500-03999 Reserved 04000 Parameter 400, Reset Function

↓ ↓

04560 Parameter 456, Brake Voltage Reduce 04570-04999 Reserved 05000 Parameter 500, Protocol

↓ ↓

05440 Parameter 544, Pulse Count 05450-05999 Reserved 06000 Parameter 600, Operating Data: Operating Hours

↓ ↓

06420 Parameter 642, Power Card Identification 06430-65536 Reserved

Handling

Parameter

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Register Maps VLT 6000

Holding Register

Description

(decimal)

00001-00008 Reserved 00009 Array index (1-255) 00010 Parameter 001, Language

↓ ↓

00170 Parameter 017, Operating State at Power-up 00180-00999 Reserved 01000 Parameter 100, Configuration

↓ ↓

01180 Parameter 118, Motor Power Factor 01190-1999 Reserved 02000 Parameter 200, Output Frequency Range

↓ ↓

02280 Parameter 228, Warning: High Feedback 02290-02999 Reserved 03000 Parameter 300, Terminal 16 Digital Input

↓ ↓

03650 Parameter 365, Terminal 45, Bus Control 03660-03999 Reserved 04000 Parameter 400, Reset Function

↓ ↓

04830 Parameter 483, Dynamic DC Link Compensation 04840-04999 Reserved 05000 Parameter 500, Protocol

↓ ↓

05710 Parameter 571, Modbus Communications Timeout 05720-05999 Reserved 06000 Parameter 600, Operating Data: Operating Hours

↓ ↓

06310 Parameter 631, Nameplate: Communication Option Ordering No. 06320-06999 Reserved 07000 Parameter 700, Relay 6, Output Function

↓ ↓

07110 Parameter 711, Relay 9, Off Delay 07120-65536 Reserved

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Register Maps VLT 8000

Holding Register

Description

(decimal)

00001-00008 Reserved 00009 Array index (1-255) 00010 Parameter 001, Language

↓ ↓

00170 Parameter 017, Operating State at Power-up 00180-00999 Reserved 01000 Parameter 100, Configuration

↓ ↓

01240 Parameter 124, Stator Reactance 01250-1999 Reserved 02000 Parameter 200, Output Frequency Range

↓ ↓

02310 Parameter 231, Filled Set Point 02320-02999 Reserved 03000 Parameter 300, Terminal 16 Digital Input

↓ ↓

03650 Parameter 365, Terminal 45, Bus Control 03660-03999 Reserved 04000 Parameter 400, Reset Function

↓ ↓

04830 Parameter 483, Dynamic DC Link Compensation 04840-04999 Reserved 05000 Parameter 500, Protocol

↓ ↓

05710 Parameter 571, Modbus Communications Timeout 05720-05999 Reserved 06000 Parameter 600, Operating Data: Operating Hours

↓ ↓

06310 Parameter 631, Nameplate: Communication Option Ordering No. 06320-06999 Reserved 07000 Parameter 700, Relay 6, Output Function

↓ ↓

07110 Parameter 711, Relay 9, Off Delay 07120-65536 Reserved

Handling

Parameter

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Process Data

Process Data is illustrated as coils in Modbus RTU.

■Status Coil Maps

(128 coils total)

Note: The coil number shown in the following table must be transmitted as ("shown value-1") in MODBUS telegrams (e.g. Coil number 0:00001 is transmitted as address 0000 in the MODBUS telegram).

■Control Word Bit Descriptions for VLT 2800

The control word is used to send commands from a master (e.g. a PC) to a slave (frequency converter).

Bit Bit = 0 Bit =1 00 Preset ref. lsb 01 Preset ref. msb 02 DC braking 03 Coasting stop 04 Quick stop 05 Freeze outp. freq. 06 Ramp stop Start 07 Reset 08 Jog 09 Ramp 1 Ramp 2 10 Data not valid Data valid 11 No function Relay 01 activated 12 No function Digital output

Te rm i na l 4 6

activated 13 Select Setup, lsb 14 Select Setup, msb 15 Reversing

Bit 00/01: Bit 00/01 is used to select between the two pre-programmed references (parameters 215-218 Preset reference) according to the following table:

Coil

Description

Number

1-16 PCD

17-32 PCD

Control Word (master → slave)

Reference Value (master →

slave)

33-48 PCD

Status Word (slave → master)

49-64 PCD2Given output frequency (slave

→ master)

65 Write parameters to eeprom (1 = true

/0=false)

66-128 Reserved

Preset ref. Parameter Bit 01 Bit 00

1 215 0 0 2 216 0 1 3 217 1 0 4 218 1 1

NB!:

In parameter 508 Selection of preset reference a selection is made to define how

Bit 00/01 gates with the corresponding

function on the digital inputs.

it 02, DC brake:

Bit 02 = ’0’ causes DC braking and stop. Brake

voltage and duration are preset in parameters 132 DC brake voltage and parameter 126 DC braking time. Note: In parameter 504 DC brake a selection is made to define how Bit 02 gates with the corresponding function on a digital input.

it 03, Coasting stop:

Bit 03 = ’0’ causes the frequency converter to

immediately "let go" of the motor (the output transistors are "shut off"), so that it coasts to a standstill.

Bit 03 = ’1’ causes the frequency converter to be able

start the motor if the other starting conditions have been fulfilled. Note: In parameter 502 Coasting stop a selection is made to define how Bit 03 gates with the corresponding function on a digital input.

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Bit 04, Quick stop:

Bit 04 = ’0’ causes a stop, in which the motor’s

speed is ramped down to stop via parameter 212 Quick stop ramp-down time.

it 05, Freeze output frequency:

Bit 05 = ’0’ causes the present output frequency

(in Hz) to freeze. The frozen output frequency can now only be changed by means of the digital inputs programmed to Speed up and Speed down.

NB!:

If Freeze output is active, the frequency converter cannot be stopped via Bit 06 Start or via a digital input. The frequency converter

can only be stopped by the following:

• Bit 03 Coasting stop

• Bit 02 DC braking

• Digital input programmed to DC braking, Coasting

stop or Reset and coasting stop.

it 06, Ramp stop/start:

Bit 06 = ’0’ causes a stop, in which the motor’s

speed is ramped down to stop via the selected ramp down parameter.

Bit 06 = ’1’ causes the frequency converter to be able

to start the motor, if the other starting conditions have been fulfilled. Note: In parameter 505 Start a selection is made to define how Bit 06 Ramp stop/start gates with the corresponding function on a digital input.

it 07, Reset:

Bit 07 = ’0’ does not cause a reset. Bit 07 = ’1’ causes the reset of a trip. Reset is activated on the signal’s leading edge, i.e. when changing from logic ’0’ to logic ’1’.

it 08, Jog:

Bit 08 = ’1’ causes the output frequency to be

determined by parameter 213 Jog frequency.

it 11, Relay 01:

B Bit 11 = "0" Relay not activated. Bit 11 = "1" Relay 01 activated, provided Control word bit has been chosen in parameter 323.

it 12, Digital output, terminal 46:

B Bit 12 = "0" Digital output has not been activated. Bit 12 = "1" Digital output has been activated, provided Control word bit has been chosen in parameter 341.

it 13/14, Selection of Setup:

B Bits 13 and 14 are used to choose from the four menu Setups according to the following table:

Setup Bit 14 Bit 13 100 201 310 411

The function is only possible when Multi-Setups is selected in parameter 004 Active Setup . Note: I parameter 507 Selection of Setup a selection is made to define how Bit 13/14 gates with the corresponding function on the digital inputs.

it 15 Reversing:

Bit 15 = ’0’ causes no reversing. Bit 15 = ’1’ causes reversing.

Note: In the factory setting reversing is set to digital in parameter 506 Reversing. Bit 15 only causes reversing when either Ser. communication, Logic or or Logic and is selected.

■Status Word Bit Description for VLT 2800

Handling

Parameter

it 09, Selection of ramp 1/2:

B Bit 09 = "0" means that ramp 1 is active (parameters 207/208). Bit 09 = "1" means that ramp 2 (parameters 209/210) is active.

it 10, Data not valid/Data valid:

B Is used to tell the frequency converter whether the

control word is to be used or ignored. Bit 10 = ’0’ causes the control word to be ignored, Bit 10 = ’1’

causes the control word to be used. This function is relevant, because the control word is always contained in the telegram, regardless of which type of telegram is used, i.e. it is possible to turn off the control word if you do not wish to use it in connection with updating or reading parameters.

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The status word is used to inform the master

(e.g. a PC) of the slave’s (frequency converter)

mode. Slav

e⇒Master.

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

Bit Bit = 0 Bit =1 00 Control ready 01 Drive ready 02 Coasting stop 03 No trip Trip 04 Not used 05 Not used 06 Trip lock 07 No warning Warning

08 Speed ≠ ref. Speed = ref.

09 Local control Ser. communi. 10 Outside

frequency range

Frequency limit

OK 11 Motor running 12 13 Voltage warn. 14 Current limit 15 Thermal warn.

Bit 00, Control ready:

Bit 00 = ’1’. The frequency converter is

ready for operation.

Bit 00 = ’0’. The frequency converter is not

ready for operation.

it 01, Drive ready:

Bit 01 = ’1’. The frequency converter is ready for

operation, but there is an active coasting command via the digital inputs or via serial communication.

it 02, Coasting stop:

Bit 02 = ’0’. The frequency converter has

released the motor.

Bit 02 = ’1’. The frequency converter can start the

motor when a start command is given.

it 03, No trip/trip:

Bit 03 = ’0’ means that the frequency converter

is not in fault mode.

Bit 03 = ’1’ means that the frequency converter

istripped,andthatitneedsaresetsignalfor operation to be re-established.

it 04, Not used:

B Bit 04 is not used in the status word.

it 07, No warning/warning:

Bit 07 = ’0’ means that there are no warnings. Bit 07 = ’1’ means that a warning has occurred.

it 08, Speed≠ ref/speed = ref.:

Bit 08 = ’0’ means that the motor is running, but that

the present speed is different from the preset speed reference. It might, for example, be the case while the speed is being ramped up/down during start/stop.

Bit 08 = ’1’ means that the motor’s present speed

is the same as the preset speed reference.

it 09, Local operation/serial communication control:

Bit 09 = ’0’ means that [STOP/RESET] is activated

on the control unit, or that Local control in parameter 002 Local/remote operation is selected. It is not possible to control the frequency converter via serial communication.

Bit 09 = ’1’ means that it is possible to control the

frequency converter via serial communication.

it 10, Outside frequency range:

Bit 10 = ’0’, if the output frequency has reached

the value in parameter 201 Output frequency

low limit or parameter 202 Output frequency high limit. Bit 10 = "1" means that the output

frequency is within the defined limits.

it 11, Running/not running:

Bit 11 = ’0’ means that the motor is not running. Bit 11 = ’1’ means that the frequency converter

has a start signal or that the output frequency is greater than 0 Hz.

it 13, Voltage warning high/low:

Bit 13 = ’0’ means that there are no voltage warnings. Bit 13 = ’1’ means that the DC voltage in the frequency converter’s intermediate circuit is too low or too high.

it 14, Current limit:

Bit 14 = ’0’ means that the output current is less than

the value in parameter 221 Current Limit I

Bit 14 = ’1’ means that the output current is greater than

the value in parameter 221 Current Limit I the frequency converter will trip after a set period of time.

LIM

and that

it 05, Not used:

Bit 05 is not used in the status word.

it 06, Trip lock:

Bit 06 = ’0’ means that the frequency converter

is not trip locked.

Bit 06 = ’1’ means that the frequency converter

is trip locked and it cannot be reset before the mains supply has been removed. The trip can be reset either with 24 V external control back up or after the power is connected again.

it 15, Thermal warning:

Bit 15 = ’0’ means that there is no thermal warning. Bit 15 = ’1’ means that the temperature limit has been

exceeded in either the motor, frequency converter or from a thermistor that is connected to a digital input.

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Serial communication reference

The serial communication reference is transferred to the frequency converter as a 16-bit word. The value is transferred in whole numbers 0 - ±32767 (±200%). 16384 (4000 Hex) corresponds to 100%.

The serial communication reference has the following format: 0-16384 (4000 Hex) Minimum ref. - Par. 205 Maximum ref.).

It is possible to change the direction of rotation via the serial reference. This is done by converting the binary

reference value to 2’ complement. See example.

xample - Control word and serial communication ref.:

E The frequency converter is to receive a start command and the reference is to be set to 50% (2000 Hex) of the reference range. Control word = 047F Hex ⇒ Start command. Reference = 2000 Hex ⇒ 50% reference.

0-100% (Par. 204

■Present output frequency

The value of the frequency converter’s present output

frequency is transferred as a 16-bit word. The value is transferred as whole numbers 0 - ±32767 (±200%). 16384 (4000 Hex) corresponds to 100%.

Output frequency has the following format: 0-16384 (4000 Hex)

Output frequency low limit - Par. 202 Output frequency high limit).

xample - Status word and current output frequency:

E The master receives a status message from the frequency converter that the current output frequency is 50% of the output frequency range. Par. 201 Output frequency low limit =0Hz Par. 202 Output frequency high limit =50Hz

Status word = 0F03 Hex. Output frequency = 2000 Hex ⇒ 50% of the frequency range, corresponding to 25 Hz.

0-100% (Par. 201

Handling

Parameter

The frequency converter is to receive a start command and the reference is to be set to -50% (-2000 Hex) of the reference range.

The reference value is first converted to 1’ complement, and then 1 is added binarily to obtain 2’ complement:

2000 Hex 0010 0000 0000 0000 0000

1’ complement 1101 1111 1111 1111 1111

2’ complement 1110 0000 0000 0000 0000

Control word = 047F Hex ⇒ Start command. Reference = E000 Hex ⇒ -50% reference.

■Control Word Bit Descriptions VLT 6000 / VLT 8000

The control word is used for transmitting commands from a master (e.g. a PC) to a slave.

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Bit Bit = 0 Bit =1 00 Preset ref. lsb 01 Preset ref. msb 02 DC braking 03 Coasting stop 04 Quick stop 05 Freeze output frequency 06 Ramp stop Start 07 Reset 08 Jog 09 No function No function 10 Data not valid Data valid 11 Activate relay 1 12 Activate relay 2 13 Choice of setup lsb 14 Choice of setup msb 15 Reversing

Bit 00/01: Bits 00 and 01 are used for choosing between the four pre-programmed references (parameters 211- 214 Preset reference) in accordance with the following table:

Preset ref. Parameter Bit 01 Bit 00

12110 0 22120 1 32131 0 42141 1

Bit 05 = "0" means that the given output frequency (in Hz) is frozen. The frozen output frequency can now only be changed via the digital inputs programmed for Speed up and Speed down.

NB!:

If Freeze output is active, the frequency converter cannot be stopped via Bit 06 Start or via terminal 18. The frequency converter

can only be stopped in the following ways:

• Bit 03 Coasting stop

• Te rm in al 2 7

• Bit 02 DC braking

• Terminal 19 programmed for DC braking

it 06, Ramp stop/start:

B wBit 04 = "0" leads to a stop in which the motor speedisrampeddowntostopviaparameter 207 Ramp-down time. Bit 06 = "1" means that the frequency converter is able to start the motor, provided the other conditions for starting are fulfilled. Note: In parameter 505 Start a choice is made of the way bit 06 Ramp stop/start is to be gated with the corresponding function of terminal 18.

NB!:

Parameter 508 Choice of preset reference is used to choose how bits 00/01 are to be gated with the corresponding

functions of the digital inputs.

it 02, DC BRAKE:

B Bit02=0leadstoDCbrakingandstop. Set braking current and duration in parameter 114 DC

braking current and in parameter 115 DC braking time. Note: Parameter 504 DC brake is used

for selecting how bit 02 is to be gated with the corresponding function of terminal 27.

it 03, Coasting stop:

B Bit 03 = "0" means that the frequency converter immediately "lets go" of the motor (the output transistors are "turned off"), which means that the motor runs freely until it stops. Bit 03 = "1" means that the frequency converter is able to start the motor, provided the other conditions for starting are fulfilled. Note: In parameter 503 Coasting stop thechoiceismadeofhowbit03istobegated with the corresponding function of terminal 27.

it 04, Quick stop:

B Bit04="0"leadstoastopinwhichthemotor speed is ramped down to stop via parameter 207 Ramp-down time.

it 05, Freeze output frequency:

it 07, Reset:

B Bit 07 = "0" leads to no reset. Bit07="1"meansthatatripisreset. Reset is activated on the leading edge of the signal,

i.e. at the change from logic ’0’ to logic ’1’.

it 08, Jog:

B Bit 08 = "1" means that the output frequency is determined by parameter 209 Jog frequency.

it 09, No function:

B Bit 09 has no function.

it 10, Data not valid/Data valid: Used for telling the frequency converter whether the control is to be used or ignored. Bit 10 = "0" means that the control word is ignored. Bit 10 = "1" means that the control word is used. This function is relevant because the control word is always contained in the telegram, regardless of the type of telegram used, i.e. it is possible to disconnect the control word if it is not to be used in connection with updating or reading of parameters.

it 11, Relay 1:

B Bit 11 = "0": Relay 1 is not activated. Bit 11 = "1": Relay 1 is activated, provided Control word bits 11/12 has been selected in parameter 323 Relay outputs.

it 12, Relay 2:

B Bit 12 = "0": Relay 2 is not activated.

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Bit 12 = "1": Relay 2 is activated, provided Control word bits 11/12 has been selected in parameter 326 Relay outputs.

NB!:

If the time-out period set in parameter 556 Bus time interval function is exceeded, relays 1 and 2 will lose their voltage if they have

been activated via serial communication.

its 13/14, Choice of Setup:

B Bits 13 and 14 are used to choose among the four menu Setups in accordance with the following table:

Setup Bit 14 Bit 13 100 201 310 411

This function is only possible if Multi-setups has been selected in parameter 0 Note: In parameter 507 Choice of Setup achoiceis made of the way bits 13/14 are to be gated with the corresponding function of

it 15, No function/re

B Bit 15 = "0" leads to no reversing. Bit 15 = "1" leads to reversing.

Please note that, in the factory setting, reversing has been selected as digit which means that bit 15 only leads to reversing, if

bus, logic or orlogic and has been selected (however, logic and only to

■Status Word Bi

The status word is used to inform the master (e.g. a PC) of the condition of the slave (VLT 6000 HVAC / VL

versing:

al in parameter 506 Reversing,

gether with terminal 19).

t Descriptions VLT 6000 / VLT 8000

T 8000 AQUA).

04.

the digital inputs.

Bit Bit = 0 Bit = 1 00 Trip Control ready 01 Drive ready 02 Stand by 03 No trip Trip 04 Not in use 05 Not in use 06 Not in use 07 No warning Warning

08 Speed ≠ref. Speed = ref.

09 Local operation Serial com. control 10 Out of frequency range 11 Running 12 No function No function 13 Voltage warning

high/low 14 Current limit 15 Thermal warning

Bit 00, Control ready: Bit 00 = "1". The frequency converter is ready for operation. Bit 00 = "0". The frequency converter has tripped.

it 01, Drive ready:

B Bit 01 = "1". The frequency converter is ready for

operation, but terminal 27 is a logic ’0’and/or a coasting

command has been received via serial communication.

it 02, Stand by:

B Bit 02 = "1". The frequency converter is able to start the motor when a start command is given.

it 03, No trip/trip:

B Bit 03 = "0" means that the VLT 6000 HVAC is not in an error state. Bit 03 = "1" means that the VLT 6000 HVAC has tripped and needs a reset signal in order for operation to be resumed.

it 04, Not in use:

B Bit 04 is not used in the status word.

it 05, Not in use:

Bit 05 is not used in the status word.

it 06, Trip lock:

Bit 06: "1" means that there is a trip lock.

Handling

Parameter

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it 07, No warning/warning: Bit 07 = "0" means there is no warning. Bit 07 = "1" means a warning has occurred.

NB!:

All warnings are described in the Operating Instructions.

it 08, Speed ≠ref./speed = ref.:

B Bit 08 = "0" means that the motor is running, but that the present speed is different from the preset

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

speed reference. This may be the case, i.e. when the speed is ramped up/down at start/stop. Bit 08 = "1" means that the present motor speed equals the preset speed reference.

it 09, Local operation/serial communication control:

B Bit 09 = "0" means that OFF/STOP has been activated on the control unit, or that the VLT 6000 HVAC is in Hand mode. It is not possible to control the VLT frequency converter via serial communication. Bit 09 = "1" means that it is possible to control the frequency converter via serial communication.

it 10, Out of frequency range:

B Bit 10 = "0" if the output frequency has reached the value in parameter 201 Output frequency

low limit or parameter 202 Output frequency high limit. Bit 10 = "1" means that the output

frequency is within the limits stated.

it 11, Not running/running:

B Bit 11 = "0" means that the motor is not running. Bit 11 = "1" means that the VLT 6000 HVAC has a start signal, or that the output frequency is greater than 0 Hz.

The serial communication reference is transmitted to the frequency converter in the form of a 16-bit word. The value is transmitted as whole numbers 0 - ±32767 (±200 %). 16384 (4000 Hex) corresponds to 100 %.

The serial communication reference has the following format:

0-16384 (4000 Hex) - 0-100 % (par. 204 Minimum ref. - Par. 205 Maximum ref.).

It is possible to change the direction of rotation via the serial reference. This is done by converting the

binary reference value to 2’s complement.

See example.

xample - control word and serial communication ref.:

E The frequency converter must receive a start command, and the reference is to be set to 50 % (2000 Hex) of the reference range.

Control word = 047F Hex. Start command Reference = 2000 Hex. 50 % reference

it 12, No function:

B Bit 12 has no function.

it 13, Voltage warning high/low: Bit 13 = "0" means that there is no voltage warning. Bit 13 = "1" means that the DC voltage of the VLT 6000 HVAC intermediate circuit is too low or too high. See the voltage limits on page 160.

it 14, Current limit:

B Bit 14 = "0" means that the output current is smaller than the value in parameter 215 Current limit I Bit 14 = "1" means that the output current is higher than the value in parameter 215 Current limit I the frequency converter will trip after the time set in parameter 412 Trip delay overcurrent, I

it 15, Thermal warning:

Bit 15 = "0" means there is no thermal warning. Bit 15 = "1" means that the temperature limit has been exceeded either in the motor, in the frequency converter or from a thermistor connected to an analogue input.

LIM

and

LIM

has passed.

The frequency converter is to receive a start command, and the reference is to be set to -50 % (-2000 He The reference value is first converted to the first complement; then 1 binary is added to

get 2’sc

2000 Hex

1 komplement =

x) of the reference range.

omplement:

0010 000

0 0000 0000 binary

1101 1111

1111 1111 binary

+1binary

2 komplement =

1110 0000 0000 0000 binary

Control word = 047F Hex. Start command Reference = E000 Hex. -50 % reference

■Serial communication reference

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Present output frequency

The value of the present output frequency of the frequency converter at any given time is transmitted as a 16-bit word. The value is transmitted in the form of whole numbers 0 - ±32767 (±200 %). 16384 (4000 Hex) corresponds to 100 %.

The output frequency has the following format:

Handling

Parameter

0-16384 (4000 Hex)

Output frequency low limit - Par. 202 Output frequency high limit).

xample - Status word and present output frequency:

E and present output frequency: The master receives a status message from the frequency converter saying that the present output frequency is 50 % of the output frequency range.

Par. 201 Output

0-100 % (Par. 201

0Hz frequency low limit = Par. 202 Output

50 Hz frequency high limit =

Status word = 0F03 Hex. Status

message Output frequency = 2000 Hex. 50 % of

the frequency range,

correspondingto25Hz.

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Supported Modbus RTU Function Codes

This section describes the following functions supported by the Modbus RTU.

Read Coil Status (01 Force Single Coil (05 Force Multiple Coils (0F

■Read Coil Statu

Description

Reads the ON/OFF status of discrete outputs (0X reference is never supported for reads.

Query

The query message specifies the starting coil and quantity starting at zero. Coils 1-16 are addressed as 0-15.

Example of a request to read coils 33-48 (Status Word) from slave device 01.

of coils to be read. Coils are addressed

s(01

s, coils) in the slave. Broadcast

) Read Holding Registers (03

HEX

) Preset Single Register (06

HEX

) Preset Multiple Registers (10

HEX

)

HEX

Field Name Example (HEX)

Slave Address 01

Functi

01 Starting Address HI 00 Starting Address LO 20 No. of Poin

ts HI

00 No. of Points LO 10 Error Check (CRC) -

Response

The coil status in the response message is packed as one coil per bit of the data field. Status is indicated as: 1 = ON; 0 = OFF. The LSB of the first data byte contains the coil addressed in the query. The other coils follow toward the high order end of this byte, and from ‘low

order to high order’ in subsequent bytes. If the returned

coil quantity is not a multiple of eight, the remaining bits in the final data byte will be padded with zeros (toward thehighorderendofthebyte). TheByteCountfield specifies the quantity of complete bytes of data.

Field Name Example (HEX)

Slave Address 01 Function 01 Byte Count 02 Data (Coils 40-33) 55 Data (Coils 48-41) AA Error Check (CRC) -

)

HEX

)

HEX

)

HEX

■ForceSingleCoil(05

Description

Forces a single co OFF. When broadcast, the function forces the same coil references in all attached slaves.

Query

The query me to be forced. Coils are addressed starting at zero.Coil1isaddressedas0.ForceData=00 00HEX (O

See exa

Field

FF) or FF 00HEX (ON).

mple 1 Start Motor, Run Speed 40%.

Name

il (0X reference) to either ON or

ssage specifies the coil reference

)

HEX

Examp

le (HEX)

Slave Address 01 Function 05 Coil Addr

ess HI

00 Coil Address LO 00 ForceDataHI FF Force Data

00 Error Check (CRC) -

Response

The normal response is an echo of the query, returned after the coil state has been forced.

Field Name Example (HEX)

Slave Address 01 Function 05 ForceDataHI FF Force Data LO 00 Quantity of Coils HI 00 Quantity of Coils LO 0A Error Check (CRC) -

■Force Multiple Coils (0F

Description

Forces each coil (0X reference) in a sequence of coils to either ON or OFF. When broadcast, the function forces the same coil references in all attached slaves.

HEX

)

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

Query

The query message specifies the coil references to be forced. Coils are addressed starting at zero. Coil 1 is addressed as 0.

See example 1 Start Motor, Run Speed 40 %.

Field Name Example (HEX)

Slave Address 01 Function 0F Coil Address HI 00 Coil Address LO 00 Quantity of Coils HI 00 Quantity of Coils LO 0A Byt Count 02 ForceDataHI(Coils

FF 8-1) Force Data LO (Coils

03 10-9) Error Check (CRC) -

Response

The normal response returns the slave address, function code, starting address, and quantity of coils forced.

Field Name Example (HEX)

Slave Address 01 Function 0F Coil Address HI 00 Coil Address LO 00 Quantity of Coils HI 00 Quantity of Coils LO 0A Error Check (CRC) -

Field Name Example (HEX)

Slave Address 01 Function 03 Starting Address HI 00 Starting Address LO 00 No. of Points HI 00 No. of Points LO 03 Error Check (CRC) -

Response

The register data in the response message are packed as two bytes per register, with the binary contents right justified within each byte. For each register, the first byte contains the high order bits and second contains the low order bits.

Field Name Example (HEX)

Slave Address 01 Function 03 Byte Count 06 Data HI (Register

40001) Data LO (Register

40001) Data HI (Register

40002) Data LO (Register

40002) Data HI (Register

40003) Data LO (Register

40003) Error Check (CRC) -

Function Codes

Supported Modbus RTU

■Read Holding Registers (03

Description

Reads the binary contents of holding registers (4x references) in the slave. Broadcast is never supported for reads.

Query

The query message specifies the starting register and quantity of registers to be read. Registers are addressed starting at zero. Registers 1-4 are addressed as 0-3.

See example 4 Write Parameter 104, Motor Frequency.

MG.10.S2.02 - VLT is a registered Danfoss trademark

HEX

)

■Preset Single Register (06

Description

Presets a value into a single holding register (4x reference). When broadcast, the function presets the same register reference in all attached slaves.

Query

The query message specifies the register reference to be preset. Registers are addressed starting at zero. Register 1 is addressed as 0.

See example 4 Write Parameter 104, Motor Frequency.

HEX

)

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

Field Name Example (HEX)

Slave Address 01 Function 06 Register Address HI 00 Register Address LO 01 Preset Data HI 00 Preset Data LO 03 Error Check (CRC) -

Response

The normal response is an echo of the query, returned after the register contents have been passed.

Field Name Example (HEX)

Slave Address 01 Function 06 Register Address HI 00 Register Address LO 01 Preset Data HI 00 Preset Data LO 03 Error Check (CRC) -

Field Name Example (HEX)

Slave Address 01 Function 10 Starting Address HI 04 Starting Address LO 19 No. of Registers HI 00 No of Registers LO 02 Error Check (CRC) -

■Preset Multiple Registers (10

Description

Presets values into a sequence of holding registers (4x references). When broadcast, the function presets the same register references in all attached slaves.

Query

The query message specifies the register references to be preset. Registers are addressed starting at zero. Register 1 is addressed as 0.

Exampleofarequesttopresettworegisters(set parameter 105 = 738 (7,38 A))

HEX

)

Field Name Example (HEX)

Slave Address 01 Function 10 Starting Address HI 04 Starting Address LO 19 No. of Registers HI 00 No of Registers LO 02 Byte Count 04 Write Data HI (Register 4:1049) 00 Write Data LO (Register 4:1049) 00 Write Data HI (Register 4:1050) 02 Write Data LO (Register 4:1050) E2 Error Check (CRC) -

Response

The normal response returns the slave address, function code, starting address, and quantity of registers preset.

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Exception Codes

■Exception Code Tables

When the frequency converter responds to the master via the Modbus serial network, it uses the function code field to indicate either a normal (error-free) response or an error (called an exception response). In an error-free response, the frequency converter simply echoes the original function code. For an exception response, the

Modbus Code (decimal)

00 The parameter number does not exist 01 There is no write access to the parameter 02 The data value exceeds the parameter limits 03 The used sub-index does not exist 04 The parameter is not of the array type 05 Thedatatypedoesnotmatchtheparametercalled 06 Only Reset 07 Not changeable 11 No write access 17 Data change in the parameter called is not possible in the present mode of the freq

converter. Some parameters can only be changed when the motor has stopped.

18 Other error 130 There is no bus access to the parameter called 131 Data Change is not possible because factory setup is selected

frequency converter will return a code that is equivalent to the original function code with its most-significant bit set to a logic 1. In addition, the frequency converter places a unique code into the data field of the response message. This tells the master what kind of error occurred, or the reason for the exception. The tables below identify the codes and describe their meaning.

Errors

Meaning

uency

Modbus RTU Errors Modbus Code

Meaning

(decimal)

64 Invalid Data Address 65 Invalid Message Length 66 Invalid Data Length or Value 67 Invalid Function Code

Codes

Exception

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VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■Appendix A - Examples

The following examples illustrate different Modbus RTU commands.

In case of malfunction please refer to the section Exception Codes.

■EXAMPLE 1: Start Motor, Run Speed 40%

Modbus function 0F

Message sent to Modbus RTU from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Slave

Address

01 0F 00 00 00 20 04 7C

Byte 8 Byte 9 Byte 10 Byte 11+12 Force Data

Coils (8-15) 04 99 19 [37] [43]

Function Coil Addr HI Coil AddrLONo. of CoilsHINo. of CoilsLOByte Count ForceDateHI

ForceDataHI

Coils (16-23)

(Force Multiple Coils).

HEX

Force Data

Coils (24-31)

Coils (0-7)

Error Check

Modbus message string: [01] [0F] [00] [00] [00] [20] [04] [7C] [04] [99] [19] [37] [43]

[7C]+[04]: Start Command: 0000010001111100 = 047C

(reversed)

HEX

(See Control Word Bit Descriptions)

Modbus message string: [01] [0F] [00] [00] [00] [20] [04] [7C] [04] [99] [19] [37] [43] [99]+[19]: NOTE: Speed Command: 4000

40% of 4000

Message returned to Modbus master from Modbus RTU

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 + 7 Slave

Address

01 0F 00 00 00 20 [54] [13]

Function Coil Addr HI Coil Addr LO No. of Coils HI No. of Coils LO Error Check

HEX

= 1999

(reversed)

HEX

=100%speed

HEX

All values are in hexadecimal.

■EXAMPLE 2: Ramp Stop Motor

Message sent to Modbus RTU from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Slave

Address

01 0F 00 00 00 20 04 3C

Byte 8 Byte 9 Byte 10 Byte 11+12 Force Data

Coils (8-15) 04 99 19 [89] [19]

Function Coil Addr HI Coil AddrLONo. of CoilsHINo. of CoilsLOByte Count ForceDateHI

Coils (0-7)

ForceDataHI

Coils (16-23)

Force Data

Coils (24-31)

Error Check

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

Modbus message string: [01] [0F] [00] [00] [00] [20] [04] [3C] [04] [00] [00] [89] [19]

[3C]+[04]: Stop Command: 000001000111100 = 043C

(reversed)

HEX

(See Control Word Bit Descriptions)

Speed Command: 0%

Message returned to Modbus master from Modbus RTU

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 + 7 Slave

Address

01 0F 00 00 00 20 [54] [13]

Function Coil Addr HI Coil Addr LO No. of Coils HI No. of Coils LO Error Check

All values are in hexadecimal.

■EXAMPLE 3: Coast Stop Motor

Message sent to Modbus RTU from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Slave

Address

01 0F 00 00 00 20 04 20

te 8

ce Data

For

Coils (8-15) 04 00 00 [0E] [81]

Function Coil Addr HI Coil AddrLONo. of CoilsHINo. of CoilsLOByte Count ForceDateHI

Coils (0-7)

te 9

ce Data HI

For

Coils (16-23)

te 10

ce Data

For

Coils (24-31)

te 11+12

or Check

Err

Modbus message string: [01] [0F] [00] [00] [00] [20] [20] [2C] [00] [00] [--]

[20]+[2C]: Coast Command: 0010110000100000 = 2C20

(reversed)

HEX

(See Control Word Bit Descriptions)

Speed Command: 0%

Message returned to Modbus master from Modbus RTU

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 + 7 Slave

Addres

01 0F 00 00 00 20 [54] [13

Function Coil Addr HI Coil Addr LO No. of Coils HI No. of Coils LO Error Check

All values are in hexadecimal.

]

- Examples

Appendix A

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

■EXAMPLE 4: Write Parameter 104

Motor Frequency, with 60 Hz

(DataType6: UINT16) (Conversion factor = 0) Modbus Function 06

Message sent to Modbus RTU from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6+7 Slave

Address

01 06 04 0F 00 3C --

Function Register AddrHIRegister AddrLOPreset Data HI Preset Data LO Error Check

Modbus message string: [01] [06] [04] [0F] [00] [3C] [error check]

Preset Single Register

HEX

[04]+[0F]: Parameter 104 = 040F

HEX

Note that the starting address of a register is the parameter number x 10 - 1 in HEX.

104 x 10 = 1040 - 1 = 1039 = 040F

HEX

[01] [06] [04] [0F] [00] [3C] [error check] [00+[3C]: Speed (60 Hz) = 3C

Message returned to Modbus master from Modbus RTU

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 + 7 Slave

Address

01 06 04 0F 00 3C --

Function Register AddrHIRegister AddrLOPreset Data HI Preset Data LO Error Check

HEX

All values are in hexadecimal.

■EXAMPLE 5: Read Parameter 514

Motor Current =3Amps

(DataType7: UINT32) (Conversion factor = -2) Modbus Function 03

Read Holding Registers

HEX

Message sent to Modbus RTU from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6+7 Slave

Address

01 03 14 13 00 02 --

Parameter 514 (5139) = 1413

Function Start Addr HI Start Addr LO No. of Points HI No. of PointsLOError Check

HEX

Note that the starting address of a register is the parameter number x 10 - 1 in HEX.

MG.10.S2.02 - VLT is a registered Danfoss trademark

VLT®2800, VLT®6000 HVAC and VLT®8000 AQUA Modbus RTU

Message sent to Modbus master from Modbus RTU

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7+8 Slave

Address

01 03 04 00 00 01 2C --

Function Byte Count Data HI (Reg

45140)

Data LO (Reg

45141)

Preset DataLOData LO (Reg

45141)

Error Check

Byte 3-byte 6: Value 0000012C

= 300 = 3 Amps

HEX

All values are in hexadecimal.

■EXAMPLE 6: Read Parameter 609 [8]

"Log: Reference"

This example shows how to read an index parameter. Holding register 9 - Array Index. Modbus Function 06

Preset Single Register

HEX

Set Array Index to 8

Message sent to Modbus RTU from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6+7 Slave

Address

01 06 00 08 00 08 --

Message sent to Modbus master from Modbus RTU

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6+7 Slave

Address

01 06 00 08 00 08 --

Function Register AddrHIRegister AddrLOPreset Data HI Preset Data LO Error Check

Modbus Function 03 Read value of para

Message sent to Modbus RTU card from Modbus master

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6+7 Slave

Address

01 03 17 69 00 01 --

Message sent to Modbu

Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 6+7 Slave

Address

01 03 02 01 90 --

Function Start Addr HI Start Addr LO No. of

Read Holding register

HEX

meter 609 [8]

No. of

Registers HI

s master from Modbus RTU

Function Byte Count Data HI Data LO Error Check

Registers LO

Error Check

Note that the starting address of a register is the parameter number x 10 -1 in HEX.

Byte 3+byte 4: 0190

=400=40%

HEX

All values are in hexadecimal.

- Examples

Appendix A

MG.10.S2.02 - VLT is a registered Danfoss trademark

www.danfoss.com/drives

175R0998 MG10S202

Rev. 2005-03-08

*MG10S202*

Danfoss VLT 2800, VLT 6000, VLT 8000 Operating guide

Specifications and Main Features

Frequently Asked Questions

User Manual