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Fantech EC Fans – Type 1 Direct Connectivity Guide

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INST-ECMODBUST1

Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
Fantech EC Fans Type 1 Direct Connectivity Guide
MODBUS Programming and Operation Guide

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide

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Service and Innovation

Australia
Adelaide Brisbane Canberra Darwin Launceston Melbourne H.O. Newcastle
Perth Sydney Townsville

(08) 8294 0530 (07) 3299 9888 (02) 6280 5511 (08) 8947 0447 (03) 6344 6888 (03) 9554 7845 (02) 4961 6088 (08) 9209 4999 (02) 8811 0400 (07) 4775 5222

New Zealand
Auckland H.O. Christchurch Wellington

(09) 444 6266 (03) 379 8622 (04) 566 0532

Asia For agents in Asian region call Eltafantech on (603) 7846 0340 or visit www.eltafantechasia.com

As part of our on-going program of product development and improvement, Fantech reserves the right to make changes to design or specification to products without notice or
obligation and to change or discontinue models.
No part of this guide may be reproduced, in any form, or by any means, without explicit written permission from Fantech.
The entire content of this catalogue is protected by copyright.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
Contents
Introduction ............................................................................................................................................ 4 Wiring configuration ............................................................................................................................... 5
Wiring Notes:..................................................................................................................................... 5 Operation registers and commands ....................................................................................................... 6
Requested Fan Speed.......................................................................................................................... 6 Motor status ....................................................................................................................................... 6 Actual Fan speed................................................................................................................................. 7 Registers for additional functionality...................................................................................................... 8 Maximal speed.................................................................................................................................... 8 MODBUS Communications General and Protocol Information.............................................................. 9 Structure of a byte .............................................................................................................................. 9 Communications process .................................................................................................................... 9
Commands from External Controller ............................................................................................ 10 Responses from the fan unit.............................................................................................................11 Read holding register ........................................................................................................................ 11 Read input register............................................................................................................................ 12 Write single register..........................................................................................................................13 Diagnostics ........................................................................................................................................ 13 Write multiple register......................................................................................................................14 Other commands .............................................................................................................................. 14

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
1. Introduction
The products within the Fantech range of EC products optionally come with RS485 serial interfaces supporting the MODBUS communication protocol for the control of fan speed and feedback of status information. This document covers the applications of MODBUS communication to achieve a level of functionality suitable for HVAC Applications. It is assumed that the reader is applying the document with the intent of configuring a control system interface to operate with a Fantech EC Fan Type 1 and has a working knowledge of MODBUS and high-level control in general.
Knowledge of general Modbus specifications is also required: - MODBUS over Serial Line Specification & Implementation guide V1.0 - MODBUS Application Protocol Specification V1.1
These documents are available in the internet at modbus.org
The general Modbus specifications form the basis for this document and are valid in full with the exception of the restrictions described in this document. Specific information relating to the data encoding and commands supported by the fan over MODBUS are outlined in Section 5 `MODBUS Communications General and Protocol Information'.
Specifics on minimum required registers to achieve functionality between an external MODBUS controller and the fan unit are described in Section 3 ` Operation registers and Commands' which denotes the register addresses and a description of the data encoding for these registers. Information for additional registers for functions above basic operation is noted in Section 4.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide

2. Wiring configuration

Fantech wiring diagram W028 denotes the overall wiring connection for all Fantech EC fans described in this document. Of all the wiring terminals available, only a number of wire connections are necessary.

This guide assumes that the following control wiring terminals are physically connected as follows:

Wiring Terminal RSA / RSA1 RSB / RSB1 GND1
NO
COM

Wire Colour Black White Blue
Red + Blue Spots Green + Red Spots

Description RS485 Interface Terminal A, D+ RS485 Interface Terminal B, DCommon ground for external controller and fan control circuit Forms alarm circuit with `COM' and opens when fan enters a fault condition. Forms alarm circuit with `NO' (optionally NC) and opens when fan enters a fault condition.

Wiring Notes:
Wires for the RS485 interface are to be of a screened twisted pair construction, 18AWG conductor size. Similar to Belden 8760.
Maximum wiring loop length for the RS485 connections on site is 1.5km with the use of the correct cabling type.
The ground terminals for the external controller and fan must be inkind through the screening of the RS485 cable interface or a suitable low resistance connection. Failure to do so may result in damage to the communications interface of the external control or fan control circuit through overvoltage. FANTECH WILL NOT WARRANT ANY PRODUCTS WHICH HAVE FAILED DUE TO OVERVOLTAGE APPLIED TO THE ONBOARD CONTROLS ELECTRONICS DUE TO MISAPPLICATION.
The NO and COM terminals of a number of fan units may be wired together to form a fault alarm `loop' that will go to open circuit upon the failure of any of the fans within the loop. However, this may not be sufficient for Run/Fault indication as the alarm does not indicate whether or not the fan is actually operating.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
3. Operation registers and commands
Fantech suggest a minimum of three operations that the external controller should be set to perform to achieve a suitable level of functionality with the Fantech EC Fan unit:
Setting Fan Speed Reading of fan fault byte periodically to check the fault status of the fan Reading of fan speed to determine run/stop status of the fan
Requested Fan Speed
Register Type: Holding Register Address : D001 Action Required: Write requested speed in % of maximum speed to the holding register address Encoding: The requested fan speed is in the form of a percentage value where 64000 represents 100% speed. 100% speed corresponds to the maximum speed (variable nMax rpm noted in the `optional parameters' section). To correlate requested speeds to an absolute speed in rpm units, follow the calculation below:
nMax [rpm] can be read as per its description in section 5.1 Maximum speed.
Motor status
Register Type: Input Register (read only) Address : D011 Action Required: Read appropriate bits in the register address to determine fan fault status The motor status register specifies errors currently detected in the fan. Encoding:

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide

Error detection for the External Modbus controller may be set to either register general errors (the FB bit notes general error status) or can provide more specific error codes if other bits are decoded in the controller software. The errors corresponding to the bits noted in the table above are as follows:

UeHigh UeLow UzLow UzHigh TFEI BLK HLL TFM FB SKF TFE PHA

Mains overvoltage Mains undervoltage DC-link undervoltage DC-link overvoltage Electronics interior overheated Locked motor Hall sensor error Motor overheated Fan bad (general error) * See note below. Communication error between master controller and slave controller Power mod overheated Phase failure

Note: Fan Bad is a general error flag and is active whenever any other error bit is set.

Actual Fan speed
Register Type: Input Register (read only) Address : D010 Action Required: Read register address to determine current fan speed in %
Encoding: The actual speed data is in the form of a percentage value where 64000 represents 100% speed. 100% speed corresponds to the maximum speed (variable nMax rpm noted in the `optional parameters' section). Therefore, if percentage speed for a data readout is not sufficient, actual operating speeds in rpm can be displayed as per the calculation below:

nMax [rpm] can be read as per its description in section 5.1 Maximum speed.
Note that if the actual speed of the fan unit exceeds the value of " nMax ", the display will be limited to a value of "1.02 * nMax.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
4. Registers for additional functionality
Maximal speed
Register Type: Holding Register Address : D119 Actions Possible : Read to determine actual speed values for the fan or limit maximum fan speed NOTE: This variable is stored in the fan controller's EPROM, and should not be written to continuously! It should only be written during initial commissioning. All parameters with speed specifications (set values, actual values) are related to this value. The value 64,000 in these speed specifications is equivalent to the maximum speed value specified here.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
5. MODBUS Communications General and Protocol Information
The MODBUS RTU protocol is used for data transmission between the external controller and fan. Data flow should be controlled by the external controller as the master, with all fan units responding as slave devices. It is important that no slave devices share the same address for this reason. MODBUS-ASCII cannot be supported. IMPORTANT NOTE: MODBUS-RTU communication with these fan units has a limitation of all communication responses being a maximum of 17 bytes in length. See the item `Read Holding Register' for more information.
Structure of a byte
According to the MODBUS over Serial Line Specification & Implementation guide V1.0. a byte has the following structure:
The definition of the parity bit ("Even", "Odd", "None") can be set with the parameter "Parity configuration" The transmission rate is variable and by default is 19,200 bps, with parity settings of 8 Data Bits, Even Parity and 1 stop bit. (8E1)
Communications process
The MODBUS over Serial Line Specification & Implementation guide V1.0 defines the following framework for the transmission protocol:
In contrast to the general specifications, the maximum telegram length is 17 bytes!

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide

Commands from External Controller
Initial synchronisation: A transmission pause of at least 3.5 bytes is used for initial synchronisation. The following byte is then interpreted as the first byte of a frame (i.e. address). The pause between the individual bytes of a frame may be a maximum of 1.5 bytes.

Address: The address field has a size of 8 bits. The address values 1..247 are permissible The address 0 is reserved for broadcast commands (i.e. commands to all fans in the network).

Command: The following commands from the "MODBUS Application Protocol Specification V1.1" general specifications are supported:

Code 0x03 0x04 0x06 0x08 0x10

Command Read holding register Read input register Write single register Diagnostics Write multiple register

Other commands are not supported.

Depending on the command concerned, the length of the device's response and the meaning of the data bits will differ. Please refer to the sections documented in `command parameters'.

CRC L / CRC H A CRC checksum is defined via the complete telegram. The polynomial for defining the checksum is 1 + x2 + x15 + x16 (i.e. XOR link to 0xA001). The initial value is 0xFFFF.

The low byte of checksum is transmitted first, then the high byte.

More detailed information about calculating the checksum can be found in the "MODBUS over Serial Line Specification & Implementation guide V1.0".

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
Responses from the fan unit
A fan will only answer if it receives a message through its own address. No answer will be sent to a broadcast address. the telegram length is at most 17 bytes. the correct number of data bytes have been sent so that the telegram can be interpreted. the checksum has been correctly recognised.
Initial synchronisation: After the command from the PC has been completed, the fan will wait for at least one transmission pause of 3.5 bytes. Depending on the command and on the processing time, the pause may be much longer (until the fan has received all the data it has requested)
Address: The address is repeated by the command from the PC (i.e. its own fan address)
Command: If the command can be processed, the command code will be repeated. If the command cannot be processed, the fan will answer with an exception.
Depending on the command concerned, the length of the device's response and the meaning of the data bits will differ. Please refer to the sections documented in `command parameters'.
CRC L / CRC H A CRC checksum is defined via the complete telegram. The way the checksum is defined is no different from the procedure described above for the command from the external controller.
Read holding register
Command code: 0x03 This command is used to write the content of a number of holding registers. Holding registers are parameters that can be both read- and write-accessed
Command from PC: 4 data bytes are transmitted:
1st holding register MSB address 1st holding register LSB address Number of MSB addresses to be read Number of LSB addresses to be read The description of the holding registers can be found at a later point.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
Answer from fan: The following data bytes are transmitted:
Byte count (number of addresses to be read * 2) Data in 1st holding register MSB Data in 1st holding register LSB Optional: Data from the following holding registers (0..n)
Exception codes: In case of error, only one data byte (the exception code) will be transmitted Exception codes: 0x02: Permissible range of the holding registers 0xD000 to 0xD37F exceeded 0x03: Maximum telegram length for answer (17 bytes) exceeded i.e. either more than 6 holding
registers or 0 holding registers were requested. 0x04: A holding register cannot be read due to a defect in the electronics
Read input register
Command code: 0x04 This command is used to write the content of a number of input registers. Input registers are parameters that only have read access
Command from PC: 4 data bytes are transmitted:
1st input register MSB address 1st input register LSB address Number of MSB addresses to be read Number of LSB addresses to be read The description of the input registers can be found in the preceding sections.
Answer from fan: The following data bytes are transmitted:
Byte count (number of addresses to be read * 2) Data in 1st holding register MSB Data in 1st holding register LSB Optional: Data from the following input registers (0..n)
Exception codes: In case of error, only one data byte (the exception code) will be transmitted Exception codes: 0x02: Permissible range of the input registers 0xD000 to 0xD01F exceeded 0x03: Maximum telegram length for answer (17 bytes) exceeded i.e. either more than 6 input
registers or 0 input registers were requested.

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Fantech EC Fans Type 1: Direct MODBUS BMS Connection Guide
Write single register
Command code: 0x06 This command is used to describe the content of one holding register.
Command from PC: 4 data bytes are transmitted: · Holding register MSB address · Holding register LSB address · MSB data to be written · LSB data to be written The description of the holding registers can be found at a later point.
Answer from fan: 4 data bytes are transmitted: · Holding register MSB address · Holding register LSB address · MSB data to be written · LSB data to be written
Exception codes: In case of error, only one data byte (the exception code) will be transmitted Exception codes: 0x02: Permissible range of the holding registers 0xD000 to 0xD37F exceeded 0x04: - The holding register cannot be written due to a defect in the electronics - There is no write protection in this authorisation level (password).
Diagnostics
Command code: 0x08 This command is used to check the Modbus function
Command from PC: The following data bytes are transmitted: · MSB subfunction code · LSB subfunction code · 1 - 11 data bytes
Only subfunction code 0000 is supported!
Answer from fan: The following data bytes are transmitted: · MSB subfunction code · LSB subfunction code · 1 - 11 data bytes

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Exception codes: In case of error, only one data byte (the exception code) will be transmitted Exception codes: 0x01: Subfunction code not supported (? 0000)
Write multiple register
Command code: 0x10 This command is used to write the content of several holding registers.
Command from PC: The following data bytes are transmitted: · Holding register MSB address · Holding register LSB address · Number of MSB addresses to be written · Number of LSB addresses to be written · Byte count (number of addresses to be written * 2) · Data to be written in 1st MSB holding register · Data to be written in 1st LSB holding register Optional: · Data to be written to the following holding registers (0..n)
The description of the holding registers can be found at a later point.
Answer from fan: 4 data bytes are transmitted: · Holding register MSB address · Holding register LSB address · Number of MSB addresses to be written · Number of LSB addresses to be written
Exception codes: In case of error, only one data byte (the exception code) will be transmitted Exception codes: 0x02: Permissible range of the holding registers 0xD000 to 0xD37F exceeded 0x03: One of the following three is possible
The number of maximum possible registers has been exceeded i.e. either more than 123 holding register data or 0 holding register data were defined.
Byte count ? 2 * number of registers Number of data bytes ? byte count 0x04: One of the following two possibilities: The holding register cannot be written due to a defect in the electronics There is no write protection in this authorisation level (password).
Other commands
All other commands are not supported. An invalid command is always answered with exception code 0x01.

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