The frequency response is DC to 100 kHz in the constant voltage (CV) mode, and DC to 10 kHz (DC to 5 kHz for PBZ40-10) in the constant current (CC) mode (it depends on the response setting).
Additionally, the frequency response of the CC mode depends on the load resistance.
It can be calculated as: fc = (rated load/load resistance) x cutoff frequency at the rated load.
Read the user’s manual for the details.