Modbus RTU Server with multiple slaves

[Nelson Mambre]

Hello,

I want to create a simulator like ModRSsim2 https://sourceforge.net/projects/modrssim2/

I created an array of mappings so that each slave can have it's own mapping. There's a single rtu connection.

I have created a master to test, if the master only send a query to 1 slave, it works correctly, but if the master changes the slave id for every query, the server will give errors. I've used com0com (Windows) to test the master and server.

In the Server I "cheat" and set the length to be ably to send a reply. Which functions should I use to manipulate the modbus queries/replies at a lower level?

Master (works with ModRSsim2 but not with my own server)

https://pastebin.com/K0r9MMT5

Slave/Server

https://pastebin.com/XZEqsh7h

Thanks,

Nelson