Hello Everyone,

Desperately looking for support to communicate using Modbus with Xojo.
Found a few references on this forum related to making use of ActiveX MBAXP from
I understand nothing about ActiveX.
Need a point to point instruction as to how to integrate MBAXP with Xojo. All I could do was install the MBAXP on my computer. Then open a new Xojo document, go to Insert → ActiveX → add the MBAXP component from there.
That creates two folders onto my workspace - MPAXPLIB & MBAXP. I then went to Window1 & dragged and dropped one instance of MBAXP. That created a box onto the Window1 with information such as Port1, 9600 baud, Closed. So far so good - very good. Now what next ?

I want to read holding register value from a device. Where do I find the documentation for the same ?
Please provide a detailed information so that any beginner just like me and other than me too can use it for future references. It shall help to make Xojo useful & accessible for a wide variety of industrial applications due to communication feasibilities with Modbus using ASCII, RTU (serial) or TCP/IP.
Furthermore, to all of you celebrating Xmas today, Greetings for the festivities !!!


I’m thinking that the ActiveX approach may lead you down many rabbit holes and not be worth the trouble in the long run - maybe better to create your own ModBus classes from scratch. @Christian_Schmitz has pointed a general direction in this thread: Modbus - #6 by Jaap_Cammeraat

talk to @ Krzysztof_Koninski1, he has experience with MODBUS communication & XOJO.

Hopefully he will post here so we all can learn :slight_smile:

I found Krzysztof by looking at his post:

Hi Gaurav, and Merry Christmas to you! I agree with Julia, creating your own code-base for your Modbus work in Xojo is the right approach. I’m using Xojo for interfacing with several industrial networks, including Modbus. Which flavor of Modbus does the device you want to read from use? Is it Modbus-RTU, and will you be connecting to the serial (RS-485) network with a Xojo application to ‘speak’ to this device?

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Hi Gaurav,
I have MODBUS-TCP module made from scratch with Xojo. I didn’t use RS485 as far, so it’s not work with it.
Also it read and write only Retain registers. If it’s ok for you than send me private message.
Best regards.