Profiler Operation Guide
This section describes the minimum steps required by an external master to move a motor using a profile generated by the profiler module. This guide contains the registers involved in the procedure.
It is highly recommended to read the Profiler Module section before following this guide.
Configure motor and perform phasing
Follow the Motor phasing guide in order to configure the motor and align the feedback to be used with the system. No mode of operation will work correctly if this is not performed.
When a forced phasing is performed, any latched movement or profiler in process will be cancelled.
Configure control loops
In order to move the motor with a profiler, the control loops used by the selected mode of operation need to be configured. Follow the Motor tuning guide to obtain a basic configuration of the control loops and apply it.
Profiler operation
Once all the pre-configuration of the system has been finished, the following steps need to be followed in order to make the motor move using the profiler.
Select mode of operation
The Mode of operation register (0x014) is made up of two main parts. The least significant 4 bits are used to select the mode of operation itself and the remaining bits are reserved for mode of operation options. These bits will be used further in this guide. However, in order to select a mode of operation, first of all the 4 least significant bits need to be written with the desired mode.
Profiler is supported on position and velocity modes.
Configure profiler limits
Before running the profiler, profiler limits need to be configured. These are the following.
Profiler Max. Velocity (0x2025 - Profiler max. velocity): The value in this register is the velocity that the profiler will aim to reach when the selected operation modes are either position or velocity. The profiler's velocity output should never exceed this value.
Profiler Max. Accel (0x2026 - Profiler max. acceleration): The value in this register is the acceleration that the profiler will use to reach the desired velocity when the selected operation modes are either position or velocity. Note that it's value should always be positive (in latest implementation)
Profiler Max. Decel (0x2027 - Profiler max. deceleration): The value in this register is the deceleration that the profiler will use to reach the final velocity when the selected operation modes are either position or velocity. Note that it's value should always be positive (in latest implementation)
For other operation modes to be supported in the future such as current or voltage, other registers will need to be implemented and configured to make use of the profiler. An example of this would be a current slope.
Configure set-point
Before running the profiler, the set-point of the operation mode to be used needs to be configured. If position mode is active, write the desired set-point to the Position Set-point register (0x020). On the other hand, if velocity mode is being used, write the desired velocity into the Velocity Set-point register (0x021).
Activate profiler
Once the previous steps have been followed, the profiler needs to be enabled. Enabling the profiler means that the set-points will no longer be copied straight into the demands of the drive, but will be redirected towards the profiler module.
To activate the profiler, select a valid mode using the Profiler Mode bits of the Modes of operation register (0x2014 - Operation mode) while keeping the selected operation mode. A table with the valid combinations of modes can be found 0x2010 - Control word.
Trapezoidal profiler
To select the trapezoidal profiler, set the Profiler Mode bits to value 0x1. If position mode was selected (the value of Standard operation mode bits is 0x4), to enable the profiler while keeping the same operation mode, a 0x14 should be written into Modes of operation.
Scurve without jerk control profiler
To select the SCurve without jerk control profiler, set the Profiler Mode bits to value 0x4. If position mode was selected (the value of Standard operation mode bits is 0x4), to enable the profiler while keeping the same operation mode, a 0x44 should be written into Modes of operation.
When changing operation mode or activating the profiler, the profiler outputs will be set to the motors actual values.
Enable power stage
Enable motor by means of the Control Word register (0x010). If a phasing procedure needs to be performed, wait until it finishes as it cancels any profile in progress.
Latch a movement
Once the profiler is active, the latest inputs (set-point and limits related to selected operation mode) need to be latched. First configure the Abs/Rel bit of the Control word register (0x2010 - Control word) to perform either a relative or absolute movement.
After configuring this, a latch needs to be performed. A movement will be latched when a rising edge is detected in the "New set-point" bit of the Control word register (0x2010 - Control word). It is necessary to read this register first to make sure that the bit is not already 1, in which case it needs to be cleared first.
After setting a 1 to this bit, the inputs will be latched, and the pre-calculations of the profiler will be performed. However, the profiler will not generate any output until the drive is in operation enabled state.
When latching a movement, it will start from the latest demand values.