mycnc:mycnc_pulse_width_setup
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mycnc:mycnc_pulse_width_setup [2019/04/17 13:31] – ivan | mycnc:mycnc_pulse_width_setup [2019/04/24 13:32] – ivan | ||
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====Selecting the Appropriate Pulse Width for your motor==== | ====Selecting the Appropriate Pulse Width for your motor==== | ||
- | A common procedure required for proper motor operation is selecting the appropriate pulse width for the signal going from the controller to the step/servo motor on the CNC machine. The pulse impulses sent from the controller to the motor have a certain width (as seen below), that cannot be too large due to the signal overlap that would occur otherwise because of each individual signal interfering with the next one. However, as seen in the following instructions from Panasonic' | ||
- | {{:mycnc:pulse-width: | + | A common procedure required for proper motor operation is selecting the appropriate |
- | {{:mycnc: | + | |
- | As another example, the Yaskawa' | + | {{: |
- | {{: | + | As another example, the Yaskawa' |
- | As such, the pulses have to have both a minimum width, such that the motor (or the particular setting of that motor, as with the Panasonic MINAS A5-series) is able to register pulses that are sent to it, and a maximum | + | {{: |
- | **In order to select such an appropriate | + | A step motor also requires a minimum pulse width, which is considerably higher than that of a servo motor (around ten to twenty times higher higher when comparing the specs for the Leadshine step motor below to the Yaskawa servo drive): |
+ | {{:mycnc:pulse-width:step-2-1.png}} | ||
- | *Choose | + | As such, the pulse impulses sent from the controller to the motor have to have a certain minimum width for the motor to be able to register those signals. However, that signal width also cannot be too large due to the signal overlap that would otherwise occur due to each individual signal interfering with the next one. This is done by ensuring the controller sends impulse signals |
- | *Convert | + | These constraints on the minimum and the maximum pulse width create a permissible range of pulse widths for each motor depending |
- | *For example, if the desired **[meters / minute]** speed is equal to 5 meters/ | + | |
- | *Locate the minimum **[seconds / step]** value of your step/servo motor (the minimum time it takes the motor to process each individual impulse) | + | ====Pulse Width Calculations==== |
+ | *Choose the speed at which your machine will move in **[meters / minute]** | ||
+ | |||
+ | *Convert the **[meters / minute]** speed with which the machine will move to the number of **[revolutions / second]** of the screw/ | ||
+ | | ||
+ | < | ||
+ | 5 meters/ | ||
+ | 80 millimeters/ | ||
+ | The value for the [revolutions / second] will be equal to 16 revolutions/ | ||
+ | </ | ||
+ | |||
+ | *Locate the minimum **[seconds / step]** value of your step/servo motor (the minimum time it takes the motor to process each individual impulse). This minimum time should be provided in the motor manual. | ||
+ | | ||
*Using the **[revolutions / second]** value and the minimum allowed **[seconds / step]** value of the motor, calculate how many **[steps / revolution]** the stepper driver will have to make. | *Using the **[revolutions / second]** value and the minimum allowed **[seconds / step]** value of the motor, calculate how many **[steps / revolution]** the stepper driver will have to make. | ||
- | *For example, if the minimum allowable | + | *//For example, if the minimum allowable |
+ | < | ||
+ | 1 ÷ (16 revolutions/ | ||
+ | The value for the number of [steps / revolution] will be equal to 7812.5 steps/ | ||
+ | </ | ||
*As discussed earlier, the value selected on the stepper motor must be equal or smaller than the number of **[steps / revolution]** obtained from the previous step for the motor to register the signal and function properly. | *As discussed earlier, the value selected on the stepper motor must be equal or smaller than the number of **[steps / revolution]** obtained from the previous step for the motor to register the signal and function properly. | ||
- | *For example, if the **[steps / revolution]** value has been calculated to be 7800 steps/ | + | *//For example, if the **[steps / revolution]** value has been calculated to be 7812.5 |
*Using the **[revolutions / second]** value and the updated stepper driver **[steps / revolution]** value, calculate the actual **[seconds / step]** value of the motor. This actual **[seconds / step]** value will always be equal or higher than the minimum allowable **[seconds / step]** value of the motor due to selecting a lower **[steps / revolution]** value in the previous steps. | *Using the **[revolutions / second]** value and the updated stepper driver **[steps / revolution]** value, calculate the actual **[seconds / step]** value of the motor. This actual **[seconds / step]** value will always be equal or higher than the minimum allowable **[seconds / step]** value of the motor due to selecting a lower **[steps / revolution]** value in the previous steps. | ||
- | | + | *//For example, if the **[revolutions / second]** value was equal to 16 revolutions/ |
+ | < | ||
+ | 1 ÷ (16 revolutions/ | ||
+ | The value for the [seconds / step] will be equal to 9.76 μs/ | ||
+ | </ | ||
*The value for the **Pulse Width** in myCNC software must be equal or higher than the actual **[seconds / step]** value of the motor. | *The value for the **Pulse Width** in myCNC software must be equal or higher than the actual **[seconds / step]** value of the motor. | ||
- | *For example, if the **[seconds / step]** value was equal to 9.8 μs/step, and an ET6 or an ET7 board was used, 12 μs would be selected from the chart in the **Common Hardware Settings** tab as it is the closest value that's higher than 9.8 μs. | + | *//For example, if the **[seconds / step]** value was equal to 9.76 μs/step, and an ET6 or an ET7 board was used, 12 μs would be selected from the chart in the **Common Hardware Settings** tab as it is the closest value that's higher than 9.76 μs// |
{{: | {{: | ||
- | *The 12 μs corresponds to Setting 7 in the chart, thus the **Pulse width** value should be set to 7. | + | *The 12 μs corresponds to Setting 7 in the chart, thus the **Pulse width** value should be set to 7 in myCNC software. |
- | | + | *//NOTE: The first value in the **Pulse Width** line refers to the first four axes of the controller (for example, the horizontal X and Y axes), while the second value refers to the other two axes of the controller (for example, the vertical Z axis). These values are set to be different if the controller used on the vertical axis is separate from that used on the horizontal, and are left the same if a single |
{{: | {{: | ||
- | *The pulse width setup is now complete. | + | *The pulse width setup is now complete. |
mycnc/mycnc_pulse_width_setup.txt · Last modified: 2024/01/22 11:05 by ivan