Serial.client module giving Permission Denied exception

Ignition
1

I’m trying to use the serial.client module to read data in from a barcode scanner. I’m running Ignition 7.7.5 on an ubuntu variant linux system.

I’ve used

cat /dev/ttyS0

to verify the electrical connections and that I am using the right port. Scanning a barcode throws the data on the terminal screen.

I end the cat command, close the terminal, and launch my Ignition client. In the startup script I call a scripting function that does the configuration, then calls:

system.serial.openSerialPort("/dev/ttyS0")

I get a Java error from java.io.ioException stating that SerOpenPort failed: Permission denied.

I know I am addressing the port correctly, because when I forgot the leading / I was getting “No such device”.

What do I have to do to get the permissions correct to access /dev/ttyS0?

2

You need to be running with root privileges or the user you’re running as needs to be a member of a certain group (on Ubuntu, I think the group is “dialout” by default… you’re on your own here though).