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Progressive Automations – Position Control Communication Protocol
Important Note : Constant load / Overload
Protection / Force Off Function
The overload protection (Overload shutdown) feature is to prevent motor burnouts and overload conditions which greatly
affect the service life. Please continue reading for the overload protection and use it accordingly.
About the terminology and mechanism of overload protection (Overload Shutdown)
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The overload protection feature will be activated when the motor exceeds a 50% duty cycle. When the cumulative
operating time is over 30 seconds without rest, the system will shut down.
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The duty cycle is the ratio of time ON versus time OFF.
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A 50% duty cycle means that the actuator is only ON for 50% of the time.
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Motor operating time includes the time in which the motor rotates/moves normally as well as the time in which the
motor draws current during stuck conditions without motor rotation.
Overload condition and shutdown case
For a better understanding, here are some examples of overload conditions where the shutdown will happen after 30
seconds of continuous operation.
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When the actuator is continuously operated for more than 30 seconds.
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When the goal position command is made outside the application's mechanical limit range.
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When a stuck condition is maintained for more than 30 seconds.
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When the duty cycle is more than 50%. The greater the duty cycle conditions, the faster the shutdown occurs, and the
lower the duty cycle, the later the shutdown occurs.
Overload shutdown disable
The overload shutdown function protects the actuator under overload conditions. In certain applications, there is a need to
operate under severe conditions, even if the overall mechanism protection is more important than the actuator, or even if
the life of the actuator is shortened. For this case, the shutdown function can be disabled through Progressive
Automations’ manager software so that the shutdown does not work during overload conditions.
Recovery after overload shutdown
Since the communication line is still functioning after shutdown, it can be restored to the initial state by the “Restart”
command or by reconnecting power. Be sure to remove the cause of overloading before restarting.
Exception and Cautions
Exception
: - Overload shutdown does not work when the actual load is heavier than the rated power even though it is an
overloaded environment. To manage the actuator lifespan, please do not apply loads heavier than the rated force capacity.
Caution 1)
When the spring is installed between the application and the actuator, or it is installed in the Z-axis (the
direction of gravity), it applies an external force to the actuator. Under these conditions, the actuator operates slightly but
continues to hold its position. If this condition persists, the actuator may invoke an Overload Shutdown in some cases. To
prevent this, use the Force-Off command while external power is applied.
Caution 2)
Each time the overload shutdown is executed, the cause of overload may eventually lead to motor damage.
Therefore, the cause of overload must be removed after the first overload shutdown so future shutdowns do not occur.
