I/O device is not defined

Description

The I/O configuration of I/O signal arg is invalid.

Consequences

This I/O signal has been rejected, and functions that depend on it will not work.

Possible causes

I/O device arg unknown. All I/O signals must reference an existing/defined I/O device.

Recommended actions

1. Make sure the I/O device is defined.
2. Make sure the I/O device name is spelled correctly.