4P642495-1– 2020.10 Page 1 of 52
Design guide Modbus Interface DIII
EKMBDXB7V1
Table of Contents
Safety Precautions .............................................................................................................................................. 3
1. Introduction .................................................................................................................................................... 3
1.1 System layout ........................................................................................................................................... 3
1.2 Limitations ................................................................................................................................................ 4
1.3 Specifications ............................................................................................................................................ 4
1.3.1 Dimensions and field wiring .............................................................................................................. 5
1.3.2 Wiring diagram .................................................................................................................................. 6
1.3.3 LED meaning ...................................................................................................................................... 6
1.3.4 Termination resistance (SS switches) ................................................................................................ 6
1.3.5 Push buttons ...................................................................................................................................... 7
1.3.6 Dipswitch meaning ............................................................................................................................ 7
1.4 Overview of compatible Daikin units ranges with DIII connection ........................................................... 8
1.5 Overview of compatibilty with other DIII centralised control equipment................................................ 8
2. Modbus communication ............................................................................................................................... 10
2.1 Modbus Interface DIII settings................................................................................................................ 10
2.2 Communication format .......................................................................................................................... 11
2.2.1 Function format ............................................................................................................................... 11
2.2.2 Character format ............................................................................................................................. 14
2.2.3 Silent internal time .......................................................................................................................... 14
2.2.5 Response time ................................................................................................................................. 14
2.3 Communication procedure ..................................................................................................................... 15
2.3.1 System initialisation ......................................................................................................................... 15
2.3.2 Monitor and operate units from the BMS ....................................................................................... 16
2.3.3 Other DIII devices exist in the same system .................................................................................... 20
3. Modbus registers .......................................................................................................................................... 21
3.1. Input registers ........................................................................................................................................ 21
3.2 Holding registers ..................................................................................................................................... 32
4. Software of Modbus Interface DIII ............................................................................................................... 40
4.1 Software releases ................................................................................................................................... 40
4.2 Software update with Updater ............................................................................................................... 40
4.2.1 Updater ............................................................................................................................................ 40
4.2.2 Method 1) Update with the PC USB cable EKPCCAB*. .................................................................... 41
4.2.3 Method 2) Update with a USB/RS485 converter. ............................................................................ 43
5. Modbus Interface DIII test operation ........................................................................................................... 45
