Light Load Detection
Light Load Detection is a operation mode that is available when the drive is in Rescue Mode (P7-15 = 1). It is used to run in the direction with the smallest load to minimize power consumption from the External UPS supply or Battery.
To Select Light Load Detections set P7-02 = 1.
Light Load Detection works by calculating the easiest direction to run with a test in each direction, then running in the easiest direction.
Below is the operating procedure of the Light Load Detection function.
When a run command is given and the Safety Chain is closed, the drive runs in the forward direction for the time specified in P7-08 at the speed set in P7-09.
The drive then stops applies the brakes using P5-01 and P5-02 respectively as per standard operation and then runs in the reverse direction for the same time and speed as the forward direction.
Notice
The drive calculates the easiest direct during the forward and reverse runs and shows the result in P7-11 or in any Digital Output with the setting 17.
The drive then stops again and applies the brake.
The brake is then released and the drive runs in the easiest direction displayed in P7-11 at the speed set in P7-03.
Below is the timing diagram as to how the Light Load Detection functions.
Note
The first direction during the test is always forward (clockwise) regardless of the direction selected from the controller.
While running the drive will indicate direction of travel by the keypad either display uP or dn. This is valid for the Light Load Detection test and the resultant run.
After the Light Load Detection test has been completed the result can be viewed with either:
P7-11 - Light Load Detection Results
Digital Output / Relay Output Function set to 17
For both parameters:
0 = Forward (Clockwise)
1 = Reverse (Anti-clockwise)
2 = Balanced (For Digital / Relay Outputs balanced is indicated with a 0).
Parameter Number | Parameter Name | Units | Default | Available Settings | Access | Change During Run | Scaling | Size (Bytes) | CAN Register | CAN Sub Index | Modbus Register |
|---|---|---|---|---|---|---|---|---|---|---|---|
P7-02 | Rescue Operation Function | N/A | 0: Basic Rescue Mode | 0: Basic Rescue Mode 1: Light Load Detection 2: UPS Easiest Direction based on Load Measurement 3: Energy Optimized | RW | N | N/A | 1 | 22BEh | 0 | 702 |
P7-08 | Light Load Detection Measurement time | sec | 1.0s | 0.0 ... 10.0s | RW | Y | 1 = 0.1s | 1 | 22C4h | 0 | 708 |
P7-09 | Light Load Detection Speed | Hz / rpm / ft/s / m/s | 5.00 | P8-02 ... P8-01 | RW | Y *Does not take effect until next travel | 1 = 0.01Hz 1 = 1rpm | 2 | 22C5h | 0 | 709 |
P7-11 | Light Load Detection Results | N/A | 0: Light direction is clockwise | 0: Light direction is clockwise 1: Light direction is Anti-clockwise 2: Balanced | RO | N | N/A | 1 | 22C7h | 0 | 711 |
Setting | Function |
|---|---|
0 | Basic Rescue Mode |
1 | Light Load Detection |
2 | UPS Easiest Direction based on Load Measurement |
3 | Energy Optimized |
There are 3 types of rescue mode operation, the following points of consideration help select the most suitable mode:
If the controller is to choose the direction of travel, then mode 0 should be used.
Mode 1 and 2 lets the drive measure which is the easiest direction of travel to consume the least amount of energy from the UPS/Battery. Mode 1 selects while in Rescue Operation, Mode 2 selects while in normal operation.
Mode 3 is when the drive output should be switched off and controlled by the motor brake.
This parameter sets the time that the drive runs for in each direction during the Light Load Detection test after enable. SO if P7-08 is set to 2s then the drive will run forward for 2 seconds then reverse for 2 seconds after a start command is given. The speed the test is conducted at is set via P7-09.
This parameter sets the motor speed ONLY during the Light Load Detection test in each direction. After the test and a direction has been chosen this speed is no longer used and the speed used after the result is set in P7-03.
Shows the result of either the Light Load Detection Test (P7-02 = 1) or the UPS Easiest direction based on measurement result (P7-02 = 2).
Value | Result |
|---|---|
0 | Light direction is clockwise |
1 | Light direction is Anti-clockwise |
2 | Balanced |