T-Series/Commands/Move At Constant Speed
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[edit] Move At Constant Speed - Cmd 22
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| Instruction Name | Move At Constant Speed |
|---|---|
| Firmware Version | 5.00 and up |
| Command Number | 22 |
| Command Type | Command |
| Command Data | Speed |
| Reply Data | Speed |
| Persistence | n/a |
| Summary | Moves the device at a constant speed based on the value specified in the Command Data. |
This instruction specifies a direction and a speed to move, rather than a target position. When this instruction is issued the device will accelerate (at a rate determined by command #43 Set Acceleration) to the speed specified by the instruction data. The device will continue moving at this speed until a limit is reached or a pre-empting instruction is issued. Negative speeds cause retraction while positive speeds cause extension.
To determine the actual speed that will result from a given data value, the following formulas may be used:
- Actual Speed
- = 9.375*(Command Data) [microsteps/sec] or
- = 9.375*(Command Data)/R [steps/sec] or
- = 562.5*(Command Data)/(R*S) [revolutions/min]
Where:
- Command Data is the absolute value of the Constant Speed Move instruction data
- R (microsteps/step) is the microstep resolution (command 37)
- S (steps/revolution) is the number of steps per revolution of the motor
For example, if S = 48, R = 64, and the Constant Speed Move instruction is issued with Data of 2922, then the device will move forward at a speed of approximately 535 revolutions per minute. For linear devices consult the section on Device Specific Information to determine the linear distance corresponding to a single step or revolution.
The maximum Data allowable is 512*R. Note that although the maximum data allowable depends on the resolution, the maximum speed possible is independent of the resolution. This can be seen by substituting Data = 512*R into the second formula above, giving a maximum speed (regardless of resolution) of 4800 steps/sec.
The device may be set to return its position continuously during the move using the set mode command (#40) bit 4. Position tracking is a reply-only command #8. If the device runs into zero position or maximum range, the device stops and the new position is returned via reply-only command #9.
This command may pre-empt, or be pre-empted by commands 18, 20, 21, 22 and 23.
