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| | [[Setpoint]] signal path converts user setpoint to ''internal setpoint''. | | [[Setpoint]] signal path converts user setpoint to ''internal setpoint''. |
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| − | ===Setpoint signal path===
| + | ;Signal path consists following main parts |
| − | Main parts are:
| + | *Input multiplier. Purpose of this is to increase resolution of input setpoint to allow more fine grained velocity & acceleration control in trajectory planner. By default [[MUL]] value is 50. |
| − | *Input multiplier. Purpose of this is to increase resolution of input setpoint to allow more fine grained velocity & acceleration control in trajectory planner. By default {{param|MUL}} value is 50. | + | |
| | *Setpoint smoothing filter. If enabled, applies low pass filter to signal reducing jitter and roughness of signal but also introduces about some delay. By default the filter has 100% attenuation at 250Hz. | | *Setpoint smoothing filter. If enabled, applies low pass filter to signal reducing jitter and roughness of signal but also introduces about some delay. By default the filter has 100% attenuation at 250Hz. |
| − | *[[Trajectory planner]]. This limits rate of change of setpoint signal based on {{param|CVL}} and {{param|CAL}} parameters. Output rate maximum rate of change: | + | *Trajectory planner. This limits rate of change of setpoint signal based on [[CLV]] and [[CAL]] parameters. Output rate maximum rate of change: |
| − | **Velocity changes max {{param|CAL}} nubmer of units per [[control cycle]] (control cycle is 400µs in most GD drives) | + | **Velocity changes max [[CAL]] nubmer of units per [[control cycle]] (control cycle is 400µs in most GD drives) |
| − | **Velocity maximum value is limited to {{param|CVL}} | + | **Velocity maximum value is limited to [[CVL]] |
| − | *Input divider. This divides setpoint signal by {{param|DIV}} to give desired output scale for ''internal setpoint''. Combination of multiplier and divider can be used change total scaling of setpoint signal. | + | *Input divider. This divides setpoint signal by [[DIV]] to give desired output scale for ''internal setpoint''. Combination of multiplier and divider can be used change total scaling of setpoint signal. |
| − | | + | |
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| | + | ;Internal setpoint matches feedback signals in position and velocity modes. The scale of feedback signals are |
| | + | *Position feedback: position sensor [[Quadrature|counter]] raw value |
| | + | *Velocity feedback: number of feedback device [[Quadrature|counts]] per one [[control cycle]]. Obtained by calculating the difference of position feedback values at every control cycle. |
| | + | *Torque: hardware specific scale, however '''Torque scaler''' knows the hardware scale and scales internal setpoint so that value of +/-16384 represents full torque scale (i.e. internal setpoint value 16384 outputs configured peak current [[MMC]] and 8192 outputs [[MMC]]/2) |
| | [[File:Driveblockdiagram setpoint v1.png|900px]] | | [[File:Driveblockdiagram setpoint v1.png|900px]] |
| − |
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| − | ===Setpoint source scales===
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| − | Different [[setpoint]] sources have different range and scale:
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| − | {| class="wikitable"
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| − | |-
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| − | ! Setpoint source !! Type !! Range !! Scale
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| − | |-
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| − | | Pulse & directon || Incremental || Infinite ||
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| − | * Position and torque mode: one pulse changes setpoint by one
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| − | * Velocity mode: pulse frequency input, setpoint = number of pulses per [[control cycle]]
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| − | |-
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| − | | Quadrature || Incremental || Infinite ||
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| − | * Position and torque mode: one edge of either channel changes setpoint by one
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| − | * Velocity mode: frequency input, setpoint = number of edges of either channel per [[control cycle]]
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| − | |-
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| − | | PWM || rowspan="2" |Absolute || Full input scale equals setpoint range of +/-16384. In loss of PWM signal, setpoint is 0. || rowspan="3" |
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| − | *Direct 1:1 absolute value in position mode
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| − | *Velocity & torque mode: +/-16384 represents full torque or speed scale
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| − | |-
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| − | | Analog || Full input scale equals setpoint range of +/-16384
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| − | |-
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| − | | Serial ([[SimpleMotion V2]]) || Absolute & incremental || Infinite
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| − | |}
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| − |
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| − | It should be noted that trajectory planner operates after multiplier meaning that {{param|CVL}} velocity limit value is not in equal scale with velocity setpoint value.
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| − |
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| − | ===Internal setpoint===
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| − | Internal setpoint is a predefined setpoint scale inside the drive. The scale of internal setpoint signals are:
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| − | *Position mode: position sensor [[Quadrature|counter]] raw value
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| − | *Velocity mode: internal goes through '''Velocity normalized''' that changes scales depending on setpoint source:
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| − | **In PWM & Analog source: Internal setpoint of +/-16384 represents whole speed range covered by {{param|CVL}} parameter. I.e. 10V input to analog input runs motor at 100% speed and -5V at -50% etc.
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| − | **In all other sources: number of feedback device [[Quadrature|counts]] per one [[control cycle]]. Obtained by calculating the difference of position feedback values at every control cycle.
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| − | *Torque mode: '''Torque normalizer''' scales internal setpoint so that value of +/-16384 represents full torque scale (i.e. internal setpoint value 16384 outputs configured peak current {{param|MMC}} and 8192 outputs {{param|MMC}}/2)
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| − |
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| | ==Controller== | | ==Controller== |
| | The default controller type of GD drives is cascaded type where each controlled variable has it's own PI or P controller. In position mode such structure is called as PIV controller. | | The default controller type of GD drives is cascaded type where each controlled variable has it's own PI or P controller. In position mode such structure is called as PIV controller. |
| − | | + | [[File:Driveblockdiagram controller.png|800px]] |
| − | The block diagram below represents simplified structure of GD drives.
| + | |
| − | | + | |
| − | | + | |
| − | [[File:Driveblockdiagram controller.png|898x898px]] | + | |
| − | | + | |
| − | <nowiki>*</nowiki>) Update rates may be drive model specific. 2500 Hz and 20 kHz apply for most drives including IONI and ATOMI. However, torque control domain on ARGON is 17500 Hz.
| + | |
| − | ==Calculation formulas and examples==
| + | |
| − | These examples focus on calculating values on a rotary motor and linear axis.
| + | |
| − | ===Constants used later in calculations===
| + | |
| − | Assuming control cycle to be 400µs / 2500 Hz (default in GD drives):
| + | |
| − | | + | |
| − | <math>f=2500</math>
| + | |
| − | | + | |
| − | Calculation of how many counts the [[feedback devices|feedback device]] produces per one physical unit:
| + | |
| − | | + | |
| − | <math>X_{FeedbackDeviceCountsPerUnit}=4\frac{P_{FBR}}{P_{AXS}}</math>
| + | |
| − | | + | |
| − | AXS is a number that tells how many physical lenght units (such as millimeters a linear axis) translates per one rotary motor revolution.
| + | |
| − | | + | |
| − | ===Example 1 - Calculating setpoint in position mode===
| + | |
| − | Here we convert physical units (such as millimeters) to setpoint value in position control mode:
| + | |
| − | | + | |
| − | <math>setpoint=\frac{P_{MUL}}{P_{DIV}}*D_{DesiredPosition}*X_{FeedbackDeviceCountsPerUnit}</math>
| + | |
| − | | + | |
| − | ===Example 2 - Calculating value for CVL parameter===
| + | |
| − | Here we convert speed (such as mm/sec, or whatever lenght units AXS represents) to {{param|CVL}} value:
| + | |
| − | | + | |
| − | <math>P_{CVL}=\frac{V_{DesiredSpeedLimit}*X_{FeedbackDeviceCountsPerUnit}*P_{DIV}}{f}</math>
| + | |
| − | | + | |
| − | ===Example 3 - Calculating value for CAL parameter===
| + | |
| − | Here we convert speed (such as mm/sec<sup>2</sup>, or whatever lenght units AXS represents) to {{param|CAL}} value:
| + | |
| − | | + | |
| − | <math>P_{CAL}=\frac{A_{DesiredAccelerationLimit}*X_{FeedbackDeviceCountsPerUnit}*P_{DIV}}{f^2}</math>
| + | |
| − | | + | |
| − | In alternative method we don't need acceleration value, but just time <math>t</math> in seconds to define how long motor should take to accelerate from zero speed to maximum speed defined by CAL:
| + | |
| − | | + | |
| − | <math>P_{CAL}=\frac{P_{CVL}}{tf}</math>
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| − | | + | |
| − | {{tip|Granity calculates real world units thus it can be used to calculate and experiment with the scales. As scales are linear, interpolation of values is viable choice.}}
| + | |
| − | | + | |
| − | ==See also==
| + | |
| − | *[[Trajectory planner]]
| + | |
| − | | + | |
| − | [[Category:Development]]
| + | |
| − | [[Category:Glossary]]
| + | |
| − | [[Category:Argon_user_guide]]
| + | |
