Specifications

YASKAWA Inverter Drive A1000 – Crane Software Application Manual
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7.1.3 Stopping Sequence
In this section we will describe the way the drive behaves when stopping. In order to prevent sudden slipping or dropping
of the load, enough torque must be generated to hold the load until the brake is completely clamped shut.
(1) When a STOP Command is entered (FWD or REV) the drive will stop using the method chosen in b1-03. If Coast
to Stop method is chosen, the brake will immediately clamp shut and sudden load jerking is likely. When using
Ramp to Stop, the drive will decelerate using the programmed ramp time until the Slip Prevention Frequency HF is
reached, except in CLV control mode where the drive will decelerate to zero speed.
(2) When the Output Frequency falls below the Brake Hold Frequency FHF (RHF), the Brake Release Command BR
will open, and the drive will expect to stop receiving the Brake Release Check BX feedback signal from external
circuitry in a time frame shorter than the S1-19 parameter, or a brake sequence fault will be triggered.
(3) The drive will hold output frequency at the Slip Prevention Frequency HF level until the Slip Prevention Time HT
has expired, and then ramp down to b2-01 or E1-09, whichever is smaller. This time should be long enough to allow
the brake to be completely clamped shut
Note:
If the primary frequency reference falls below the FRF (RRF) or the FHF (RHF) without a STOP Command being entered,
the drive will continue running at the higher of these two frequencies. If the frequency reference is input from analog
terminal A1, and the signal level for this terminal is set to -10V - +10V (H3-01 = 1), the stopping sequence is executed
when the frequency reference falls below the setting of parameter b2-01, or if the frequency reference equals the
minimum output frequency (E1-09) for more than 100 ms. Also when H3-01 = 1, if a frequency reference lower than
E1-09 is input, drive output will be interrupted (baseblock).
7.1.4 Forward/Reverse Switching
In control modes without encoder feedback (open loop), the drive cannot switch between forward and reverse directions
(zero speed cross) without activating the brake. When a Run Command is entered for the direction opposite to the one
the drive is going, the complete stopping sequence described in the last section will be executed and the drive will only
begin the starting sequence when the brake has been completely clamped shut.
In closed loop control modes, the drive can switch continuously between FWD and REV directions (zero speed cross)
without activating the brake. Note that in some situations the brake may still be activated, especially when using Run
Command Minimum On-Time, described in section 7.2.
The brake will be applied in all control modes when switching between FWD and REV directions if the frequency
reference is below the Brake Release Frequency FRF (RRF) level.
7.1.5 Time Charts
In this section brake sequence time charts are shown for all control modes. In the first three time charts we assume that
run commands and frequency reference are input from external terminals and that the frequency reference is constant
and higher than FRF (RRF). Also they do not show FWD/REV switching scenarios.