Hitachi WJ200-001S Instruction Manual page 157

372
Stop Mode / Restart Mode Configuration: / – You can configure how the
inverter performs a standard stop (each time Run FWD and REV signals turn OFF).
Setting  determines whether the inverter will control the deceleration, or whether
it will perform a free-run stop (coast to a stop). When using the free-run stop selection,
it is imperative to also configure how you want the inverter to resume control of motor
speed. Setting  determines whether the inverter will ensure the motor always
resumes at 0 Hz, or whether the motor resumes from its current coasting speed (also
active frequency matching
called ). The run command may turn OFF briefly, allowing
the motor to coast to a slower speed from which normal operation can resume.
In most applications a controlled deceleration is desirable, corresponding to =.
However, applications such as HVAC fan control will often use a free-run stop (=).
This practice decreases dynamic stress on system components, prolonging system life.
In this case, you will typically set = in order to resume from the current speed
after a free-run stop (see diagram down below: active frequency matching resume). Note
that using the default setting, =, can cause trip events when the inverter
attempts to force the load quickly to zero speed.
NOTE: Other events can cause (or be configured to cause) a free-run stop, such as power
loss (see "Automatic Restart Mode" on page 3-44), or an intelligent input terminal [FRS]
signal. If all free-run stop behavior is important to your application (such as HVAC), be
sure to configure each event accordingly.