Are you referring to Vacuum Florence Display or Variable Frequency Drive (also called frequency inverter)?
If it is the Vacuum Florence Display and conforms to Hitachi HD44781 interface then it can be attached to the PLC's LCD port.
If you are referring to frequency inverter, then it depends on what kind of interface is available on the VFD itself. It could be an analog input, PWM input or serial RS485 inputs. The T100MD+ PLC is able to interface to any of these interface. The PLC has two channels of 0-5V analog outputs that can connect to the VFD analog input and it is also able to send/receive ASCII or binary data via its RS485 port, which makes it possible to interface to VFD via serial interface easily and accurately.