I have to devices in communication with modbus protocol. Master is PC and slave is compressor(100ft line,RS485 standard, modbus RTU protocol). I have to build a setup which will show how much the error in communication. I am coupling some white noise to the line and some burst signals too. I could see error has happened in communication from communication log file which is getting from the Omnimbt software that I am using in master. But instead of this I need to get the BER(bit error rate) and show persons who will be monitoring the performance of modbus communication. Can anybody suggest some possible ways for doing this?