You're right. USB-Serial adaptors aren't the most compatible peripheral in the world.
But my problem is different, 'cause i use a Serial to Ethernet adaptor (Moxa calls it "device server"). If i install a driver on my PC, i got a virtual COM port though ethernet.
When i use modpoll for test (www.focus-sw.com/fieldtalk/modpoll.html) everything works:
D:\>modpoll -m enc -r 8196 -1 -p 4001 *MyIPAddress*
modpoll - FieldTalk(tm) Modbus(R) Polling Utility
Copyright (c) 2002-2006 FOCUS Software Engineering Pty Ltd
Visit http://www.modbusdriver.com for Modbus libraries and tools.
Protocol configuration: Encapsulated RTU over TCP
Slave configuration...: Address/Id = 1, start reference = 8196, count = 1
Communication.........: *MyIPAddress*, port 4001
Data type.............: 16-bit register, output (holding) register table
Polling slave ...
But i can't select "Encapsulated RTU over TCP" on Mango (AFAIK, this protocol is supported).
I try to configure an Modbus IP data source without luck.
Transport Type: TCP
also works fine with the Moxa 5130 (a basic Ethernet/RS485 SDA that is not Modbus-aware) for those Modbus slaves that can handle the 6-byte Modbus TCP-RTU header forwarded over RS485.
Therefore... My Modbus slave is incompatible with mango?
Thanks a lot!!