IMPULSE
®
•G+ & VG+ Series 4 Technical Manual
November 2020
Page 100
5.2.15 Anti-Shock
Anti-Shock is a Hoist NLB feature on the IMPULSE
®
•VG+ Series 4 VFD in the Flux Vector control method. The
torque output of the hoist is continuously monitored, and when it increases above a threshold (C07-15 and C07-
16), the hoist automatically decelerates and waits for the torque to stabilize before smoothly re-accelerating (C07-
17 and C07-18). Anti-Shock is designed to maximize hoist operational efficiency while minimizing crane structure
fatigue.
Initial Setup and Adjustment
1. Choosing an option to enable/disable Anti-Shock:
a. Setting C07-12 to 0 (Disabled) ensures Anti-Shock does not function.
b. Setting C07-12 to 1 (Enabled) allows Anti-Shock to run always.
c. Setting C07-12 to 2 (Enbl, Not In MSpd) will block Anti-Shock when Micro-Speed is enabled.
d. Setting H01-xx to 4B (Anti-Shock OFF) sets a digital input which, when enabled, will block Anti-Shock. This
allows Anti-Shock to be enabled or disabled by an external input.
2. Run the hoist, unloaded, in the UP direction. Note the value of U01-09 and enter that approximate value into
C07-23.
To make Anti-Shock less sensitive to light loads and more sensitive to heavy loads:
1. Increasing C07-15 (Torque Delta) to a higher percentage increases the torque spike magnitude that is required
to trigger Anti-Shock.
2. Increasing C07-16 (Detection Time) to a higher time widens the window of time that a torque spike is looked
for.
To make Anti-Shock more sensitive to light loads:
1. Decreasing C07-15 (Torque Delta) to a lower percentage lowers the torque increase magnitude that is required
to trigger Anti-Shock.
2. Increasing C07-16 (Detection Time) to a higher time widens the window of time that a torque spike is looked
for.
Troubleshooting
Anti-Shock is triggered when the load is already in the air:
Cause: This is caused by a torque increase due to acceleration, which falls within the parameter settings for
triggering Anti-Shock.
Corrective Action:
1. Increasing C07-14 (Re-Accel Delay) to a higher time may help remedy this occurrence.
2. Increasing C07-15 (Torque Delta) and decreasing C07-16 (Detection Time) will require a higher torque spike to
occur in a shorter amount of time.
When Anti-Shock is triggered, the VFD faults to an OV (Overvoltage) or OC (Overcurrent):
Cause: By default, Anti-Shock is configured to decelerate very quickly when a torque increase is detected. The
deceleration rate may cause a rapid increase in voltage or current, which may fault the VFD.
Corrective Action:
1. Increasing C07-18 (Smoothing Decel) will increase the time it takes for the VFD to decelerate directly after the
torque spike is detected. Spikes in voltage and/or current will be reduced.
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