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Modbus Constructor is supported as usual. Happy new year!
Modbus Constructor 1.9 Released. "Black fields" bug fixed. Trial period renewed.
Modbus Constructor 1.7 is compatible with Windows 10.
Modbus Reader 1.6.2 released.
Modbus Constructor 1.6.0 and Modbus Reader 1.6.0 released.
Modbus Reader 1.3.0 Released.
Modbus Constructor 1.1.12 Released. Some minor bugs fixed. Trial period renewed.
Modbus Constructor 1.1.11 Released. Trial period renewed.
Modbus Reader 1.2.14 Released. Some minor bugs fixed.
A prerelease of the version 1.2 of Modbus Reader is now available. Data logging capability is added for a single device as well as for multiple devices.
ModBus Constructor v1.1 Final Release is available (several critical bugs fixed, performance is improved).
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QuickStart Guide in French and German added to download area.
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QuickStart Guide is now available in Russian, Italian and Spanish!
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Modbus Constructor v1.0 RC1 Released.
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I have created a project which contains a few holding registers with addresses: 40001, 40002 and so on. But Modbus Reader reports Exception 2: ILLEGAL DATA ADDRESS.
The thing is, that notation like 4xxxx is not a pure address. It is alias that defines both address and type of Modbus item. For example:
40001 is holding register with address 1 (or 0);
00001 is coils with address 1 (or 0);
Two previous aliases are very common. It is good practice, when a manufacturer defines clearly such a notation in a user's manual.

Why Modbus Constructor is not a SCADA system?
Modbus Constructor and Reader are simple and convenient tools for communication with Modbus devices. There are useful for hardware and software developers and field engineers. If they would be a SCADA they were not convenient or not simple.

Where can I get Modbus protocol specification?
Use the following link: http://modbus-ida.org/specs.php

Does Modbus Constructor meet to Modbus IDA specifications?
The application has been fully tested with Modbus TCP toolkit, which provides a serial interface too.

Could you help me to implement Modbus slave on my microcontroller?
Of cause! Download an example project simple Modbus slave for Atmel AvrStudio and WinAVR. The target platform is Atmega2561, but it can be easily ported to any AVR or other microcontrollers.
Do not hesitate to ask if any question!
Design by Kury