It depends on the setting of servo parameter "[PA03] Absolute position detection system" whether the HPR request flag ("[Md.31] Status": b3) turns ON or not.
The flag turns ON in the following cases:
(1) "1: Enabled (absolute position detection system)"
    • When the machine HPR has not been executed at the absolute position system
    • When a machine HPR operation starts
    • When the absolute system has not been set
    • When "[PA14] Rotation direction selection/travel direction selection" is changed
    • When changes of servo amplifiers or motor encoders are detected [RD77GF only]
    • When the MR-J4-GF was not connected at the previous establishment of the home position for virtual servo amplifier connection [RD77GF only]
    • When the electronic gear is changed [RD77GF only]

(2) "0: Disabled (incremental system)"
    • System's power supply on or reset
    • Servo amplifier power supply on
    • Machine HPR start
    • When the electronic gear is changed after HPR execution [RD77GF only]