Mitsubishi Electric FR-F720P-0.75K to 110K Instruction Manual page 407

3 SERIAL number
Check the SERIAL number indicated on the inverter rating plate or package.
• SERIAL number check
Refer to the inverter manual for the location of the rating plate.
Rating plate example
 2
Symbol Year
The SERIAL consists of one symbol, two characters indicating production year and month, and six characters indicating control number.
The last digit of the production year is indicated as the Year, and the Month is indicated by 1 to 9, X (October), Y (November), or Z (December).
Z 
Month Control number
SERIAL
8/8 BCN-C22005-639