[Bug]: The results returned by Modbus RTU read operations are always byte arrays

[Joooooooooooooooooooooooooooooooooooker]

What happened?

I am currently using the latest 0.13.0-snapshot for Modbus protocol testing. When using Modbus TCP, everything works as expected: the data type written matches the data type returned by the read operation. However, when using Modbus RTU, the write operation works normally, but the read operation always returns a byte array. For example:

Write: builder.addTagAddress("tag5", "400005:SINT", new PlcSINT(5))
Read: builder.addTagAddress("tag5", "400005:SINT")
Result: Value[tag5]: [0, 5]

Write: builder.addTagAddress("tag41", "400053:LINT", new PlcLINT(38))
Read: builder.addTagAddress("tag41", "400053:LINT")
Result: Value[tag41]: [0,0,0,0,0,0,0,38]

Version

0.13.0-SNAPSHOT

Programming Languages

• plc4c
• plc4go
• plc4j
• plc4net
• plc4py

Protocols

• AB-Ethernet
• ADS /AMS
• BACnet/IP
• C-Bus
• CANopen
• EtherNet/IP
• Firmata
• IEC-69870
• KNXnet/IP
• Modbus
• OPC-UA
• Profinet
• S7
• S7-light

[chrisdutz]

Thanks for reporting these RTU issues. I agree we should address them.
The main problem for me with Modbus RTU is, that I don't really have devices to test with.
While for most of the other protocols, I have test-hardware sitting here, for which I can run my tests against, for Modbus RTU (And ASCII) the one device that I had, seems to have gone into a limbo-state where it no longer responds.

Would you be willing to invest into having this fixed? I am asking, because I no longer address issues without financial support. Others might, but I had to stop doing so. I guess in a case (and your other issue) like this I would expect something round 300€ (together). If you're ok with this, we can discuss the details privately. This is mainly to cover the expenses for maintaining my hardware test-suite.