Data Acquisition to PC/Microcontroller from a RS485 compliant device


Thread Starter


I have a digital measuring instrument (programmable), which measures values, and shows it on a LCD screen.
However it has a refresh of 1 sec
It can transmit at a rate up to 38400 bauds
It is rs485 compliant {MODBUS compliant}
I need to design a system which shall acquire data from this device.

Please do give me some idea as to how i should design this system... resources links ideas welcome...

Can u give me idea whether Microcontroller (and which) or PC is suitable for this purpose.

Thanks a lot


Andrzej Sokulski

Hi Koushal
If You want connect the device to PC you should convert RS485 to RS232 and write Modbus driver in C++ or VB (I have some vb projects if You want) or buy a program like Modbus OPC server. If you want connect the device to PLC, I think the Modicon Momentum will be suitable. It has RS485 port and XMIT function for Modbus protocol.

Best Regards
Andrzej Sokulski
[email protected]

David Coffey


Since you asked. offers various products that may be able handle your needs.

If you are connecting it to a PC you will need a RS232/RS485 convertor. If you wish the PC to show the readings, graph them, and log the values to disk we have an economical HMI program for modbus devices called ISEE-Modbus at