I have successfully used the OBD-II Uart board with Tera Term but am trying to use it with a programmable logic controller via direct RS-232 and am not getting the same data back after commanding the same request. I can only assume the message I am sending is the same at this point. This led me to wonder what data type the board sends out - is it just plain binary and whatever is receiving the data interprets it as necessary? The PLC is reading it as decimal, but even when that is converted to hex it’s different than what I get in Tera Term…
Kindly check if there is any baud rate mismatch at any point in your current project.
No, I have checked that several times and the PLC is set up the same as tera term in regard to baud, parity and stop bit, thanks. I’ve used the PLC to get data from other serial devices successfully, but since I didn’t have any problems I didn’t learn as much with those projects :).
OBD UART outputs TTL serial, not RS-232. You need a converter like a [MAX3232 in between the two to convert TTL to RS-232.](SparkFun Transceiver Breakout - MAX3232 - BOB-11189 - SparkFun Electronics)
Ah that makes sense, so the FTDI basic usb adapter board does the job when using tera term. I see the TTL to RS232 boards spark fun makes now. Thanks!