I wanted to check Data of RS 485-Modbus RTU on PC via Hyper terminal of a weighbridge and also some one can suggest company to write program for Trucks loaded in Visual Basic?
>I wanted to check Data of RS 485-Modbus RTU on PC via Hyper terminal of a
>weighbridge and also some one can suggest company to write program for
>Trucks loaded in Visual Basic?
Due to Modbus being 8-bit binary and having timing requirements down to the millisecond, use of Hyperterminal will be nearly impossible.
Instead go online and find one of the many 'free' Modbus/RTU master/poller tools (search for any of these: ModScan32, modpoll, simple modbus, Modbus PLC simulator)
I think modbus.org has some resource pages which cover public open-source Modbus/RTU code in various languages, which would include C/C++, VB, Java and so on.
I don't think timing will be much of an issue, this is handled by your serial port with buffering, as long as you are monitoring the traffic (as opposed to acting as a slave). I recommend using a serial port monitor. The one from HDD works well but is not free anymore it seems. This works if your computer is one of the communicating parties. If your computer is completely separate from the communication stream, you might as well use hyperterminal, as 485 allows you to connect many nodes to the wires. Of course the modbus specific tools might make life easier for you in any case.
> I wanted to check Data of RS 485-Modbus RTU on PC via Hyper terminal
You can't, MODBUS RTU is in unsigned binary mode!
Hyper terminal can only deal with ASCII codes wich are on to bytes instead of one in binary.
Maybe you can turn on your devices in MODBUS ASCII and then see the communication frames through Hyper terminal.
However, if it's an electrical issue, you can check with a scope on receiver side if the impulsional shape (the line must be terminated by a resistor equal to the cable impedance to avoid line reflections) and the levels are corrects (+/- 250mV to +/- 5V for RS422/485).
