Modbus Parameter Specifications

Table Of Contents
MODBUS ACE V1.00
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ebm-papst Mulfingen GmbH & Co. KG
Bachmühle 2 ·74673 Mulfingen ·Phone: +49 (0) 7938/81-0 ·Fax: +49 (0) 7938/81-110 ·www.ebmpapst.com ·info1@de.ebmpapst.com
DocNo.: 634505DocNo: 446144DocNo.:358982DocNo.:322523DocNo.:309753DocNo.:303997DocNo.:276241DocNo.:256078DocNo.:196392 ·Template: 2 dated 10/6/2003 ·File: ext001931381.docx ·Last printed 9/30/2019 10:29:00
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Form 1003
All the serial numbers found are then sorted in ascending order in the master.
A MODBUS address is allocated to each fan by way of the serial number.
For this, 2 commands are required for each fan:
Set holding register fan address (D100): F7 46 SNo SNo SNo SNo SNo SNo D1 00 00 Add CS CS
Set holding register reset (D000) to 0x02 Transfer parameter:
F7 46 SNo SNo SNo SNo SNo SNo D0 00 00 02 CS CS
SNo = fan serial number established; Add = allocated MODBUS address
Extension of address space
A maximum of 247 fans can be addressed with standard MODBUS commands.
The commands with addressing by serial number make it possible to address any number of ebm-papst fans
with MODBUS interface. In this case the fan address is not made up of just one byte but rather of 7 bytes
(MODBUS address + 6-byte serial number). This address is set at the factory and cannot be changed.
The serial number must be known to the master device (e.g. PC) for addressing, as a scan of all serial
numbers is not possible on account of the large number involved. See above for determination of serial
number (Initialization of installation).
With an extended address space, use can only be made of commands with addressing by serial number.
Collisions are inevitable if standard commands are used, as several fans have the same MODBUS address.
Determination of unknown MODBUS address
There must not be more than one fan connected to the bus
Command 0x43 Read holding register addressed by serial no. or 0x44 Read input register addressed by
serial no. in Broadcast addressing:
MODBUS address and serial number identifier are given as 0x00
The connected fan responds with its MODBUS address and serial number
1.3.7 Other commands
All other commands are not supported.
The response to a command is always the exception code 0x01.