No, the green LED has three possible states when the PD20-1- is powered:
1) Slow flashing for normal operation with TMCL firmware
2) Fast Flashing when the firmware is being reset to factory values
3) Permanently on if there is no valid firmware uploaded or during a firmware update
If the LED is off even though the PD20-1- is powered up, then that indicates a faulty board. Please contact the distributor you purchased the PD20-1- from to get a replacement