"New" modbus master/rtu module


Thread Starter

Mario de Sousa

Hi all,

I have finally brought Phil's modbus module to work with the new generic io library. It is in the cvs now.

The RTU protocol was completely re-written in order to take into account aborted frames and slow CPUs executing the code. Even though it doesn't look like a lot of code, it took a lot of thinking to get it right.

Next week I will probably commit a demo explaining how to configure the module.

I am currently working (slowly) on the ascii version.

Please note that the code was tested several iterations ago, before I added a few optimisations. I have not had the chance to check it again against another modbus device. It will probably have to wait until mid-January.



Mario J. R. de Sousa
[email protected]

The box said it requires Windows 95 or better, so I installed Linux _______________________________________________
LinuxPLC mailing list
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I'd like to help out if possible. I'm not much on Linux, but I do have access to a fair number of Modbus devices to test against. Do you have need of a "User Level Test Geek"?

hi, I do not know how to publish a doubt about modbus in this forum. Perhaps you know the solution for my problem. I need transform RS-232
data to Modbus. I want to know if exist some hardware, without PLC, that perfoms this operation. Thank you very much.

Gordon Arnold

One soultion for converting RS232 data to MODBUS is via our FieldServers FS-B2010 and FS-B4010 which can be reviewed at www.fieldserver.com
FieldServer Technolgies writes protocol drivers for many serial devices so that the data can be utilized via MODBUS, Ethernet protocols and
various Fieldbus protocols.