The baud rate you select in the code should match the baud rate specified in the configuration utility. If the Jrk is connected via its RX and TX lines, you will need to set the Jrk’s serial mode to “UART” and select the baud rate you want to use in the “Input” tab of the Jrk G2 Configuration Utility. (You could remove the code that sets the baud rate.) Also, instead of using this code, you might consider running the Jrk G2 Command-line Utility (jrk2cmd), which uses the native USB interface, since it can take care of all of the low-level details of communication for you. The baud rate specified in this code and in the Jrk’s settings do not have to match because the serial bytes are transferred via USB. If the Jrk is connected to your PC via USB, you will need to set the Jrk’s serial mode to “USB dual port” in the “Input” tab of the Jrk G2 Configuration Utility. Also, you might need to change the const char * device line in the code that specifies what serial port to connect to. The Jrk’s input mode should be set to “Serial / I2C / USB”, or else the “Set target” command will not work.

For a very similar example that only works on Windows, see Section 15.6. It demonstrates how to set the target of the Jrk by sending a “Set target” command and how to read variables using a “Get variables” command. The example C code below uses parts of the POSIX API provided by Linux and macOS to communicate with a Jrk G2 via serial.

Linux c serial port example