drivers for waveshare RS 485 usb serial converter for huangyang vfd

Thanks guys, I'll give it a try later today.

In the mean time:

The new adapter has a connector for ground, the old one did not. Can this be part of the problem?
 

tommylight wrote:

In a terminal
lsusb
before and after inserting the waveshare, post results here.
Results:

sven@svencnc:~$ lsusb
Bus 002 Device 002: ID 8087:8000 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 005: ID 10ce:eb70 Silicon Labs
Bus 003 Device 003: ID 046d:c408 Logitech, Inc. Marble Mouse (4-button)
Bus 003 Device 004: ID 0ac8:3420 Z-Star Microelectronics Corp. Venus USB2.0 Camera
Bus 003 Device 002: ID 05e3:0608 Genesys Logic, Inc. Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
sven@svencnc:~$ lsusb
Bus 002 Device 002: ID 8087:8000 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 005: ID 10ce:eb70 Silicon Labs
Bus 003 Device 003: ID 046d:c408 Logitech, Inc. Marble Mouse (4-button)
Bus 003 Device 006: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Bus 003 Device 004: ID 0ac8:3420 Z-Star Microelectronics Corp. Venus USB2.0 Camera
Bus 003 Device 002: ID 05e3:0608 Genesys Logic, Inc. Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

So this is the new device:
Bus 003 Device 006: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC

I found where the ttyusb0 and ttyusb1 for the inverter are called, changing these to the usb port in use did not make a difference.
EDIT: seems to need to be at ttyusb0 or linuxcnc will not start.

Adding to existing posts makes a mess, continuing...

It seems that if linuxcnc cannot find the device, it closes with an error, calling out the missing device.

Does this mean that the device is defective or connected wrong?

Might be permissions issue, search google for "arduino permission denied" for a way to add user to dialout group and maybe might also need to set permissions to USB port.

I did come across that, group seems ok, am i right:

 sven@svencnc:~$ groups sven
sven : sven dialout cdrom sudo audio video users

I'll look in to permissions for the usb port.

I followed:
www.xmodulo.com/change-usb-device-permission-linux.html

and now have:
crw-rw---- 1 root dialout 188, 0 29 nov 15:20 /dev/ttyUSB0

For good measure I switched wires again for testing.