Posted 2 Dec 2014 Hi All, We have a free Modbus Master Utility that you can use to test communcation to your Modbus Slave modules and PLC. Please let us know your feedback. http://www.icpdas-usa.com/documents/modbus/modbus_master_tool.zip If we can help with any future projects, with remote IO, controllers or communicaiton, please feel free to contact us. Share this post Link to post Share on other sites
Posted 4 Dec 2014 Very nice little package. Easy to find the setup window. Self-explanatory connection setup for reads. I love the Base 0, Base 1, dual columns with the leading 4xxxxx for the holding registers in the Base 1 column. I had to check the notes for how to write a value with set value. But it works. I had to experiment and highlight both registers to write a floating point. My only suggestion would be offer a swapped byte floating point option, because some slaves do not have the ability to change their floating point format. You can expect to see screen shots of this program appear in forums (with a link to your download) when I suggest they use a Master tool first to establish comm or when I attempt to explain the dreaded Modbus one-offset. I suspect you don't care if we pass it around? The only quirk was finding a .rar compressed file coming out of an unzipped .zip file. But I'm guessing that most people who will be using a generic Modbus test Master will have extractors for both. Share this post Link to post Share on other sites
Posted 2 Jan 2015 I just discovered that the Modbus master utility only handles one of the two common IEEE 754 32 bit floating point formats. The Modbus world is split about half and half as to the these two floating point formats, which limits the utility's usefulness in about half of the Modbus apps where the slave is using FP. Share this post Link to post Share on other sites