Modbus Parameter Specifications

Table Of Contents
MODBUS ACE V1.00
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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
1.3.6.5 Applications
Initialization of an installation
All ex works fans have the same address 1. To be able to address each fan individually in the case of an
installation made up of several fans, this address has to be changed so that each fan has a different address.
Standard procedure (command 0x06 Write single register):
1. Switch on the first fan (leave all others switched off)
2. Change the address using the command 0x06 Write single register
3. Switch on the next fan
4. Repeat steps 2 and 3 until all fans have an individual address
Procedure if serial numbers are known (e.g. printed on nameplate)
1. Switch on all fans
2. Change the addresses using the command 0x46 Write single register addressed by serial no.
Procedure if serial numbers are not known:
1. Switch on all fans
2. Identify the serial numbers using the command 0x43 Read holding register addressed by serial no. or
0x44 Read input register addressed by serial no. in Broadcast addressing with collision detection
3. Once a serial number has been identified:
Change the MODBUS address using the command 0x46 Write single register addressed by serial no.
The advantage over the standard procedure is that all the fans can be switched on simultaneously on
initializing an installation. Each fan can be addressed individually despite having the same address 1. The
master device (e.g. PC) can allocate an individual address to each fan without the need for any switching
operations in the installation.
Implementation in master device (e.g. PC):
The following procedure is recommended for implementation in a master device if serial numbers are known:
1. The master device is informed of all serial numbers by way of manual input
2. A MODBUS address is allocated to each fan by way of the serial number.
For this, 2 broadcast commands are required for each fan:
a. Set holding register fan address (D100):
00 46 SNo SNo SNo SNo SNo SNo D1 00 00 Add CS CS
(CS = CRC checksum)
b. Set holding register reset (D000) to 0x02 Transfer parameter:
00 46 SNo SNo SNo SNo SNo SNo D0 00 00 02 CS CS
SNo = fan serial number established; Add = allocated MODBUS address