Delta Electronics AC Motor Drive VFD-E User Manual page 290

5. When it is changed to "PLC2", RS-485 will be used by PLC.
6. When it is in PLC1 and PLC2 mode, the function to reset all parameters to factory setting
is disabled (i.e. Pr.00.02 can't be set to 9 or 10).
Revision June 2008, 04EE, SW--PW V1.11/CTL V2.11
Appendix D How to Use PLC Function|
D-7