Private MachPro Planner Reference
1 Introduction
1.1 Purpose and scope
A motion planner calculates the commanded trajectory and controls changes in velocity and acceleration. MachPro provides Trapezoidal and PureMotion planners.
This reference follows the relevant M31 setup topics: axis configuration, motor motion settings, final machine testing, advanced behavior, parameter reference, troubleshooting, and application notes. Wiring and installation procedures remain in the setup manual.
M31 Motion Control Setup Manual: Open Document
==Confirm the supported MachPro build. The source draft identifies the release planned for 15 October 2026 and later; a minimum build number is not supplied.==
2 Axis Configuration
2.1 Identity and calibration
An Auxiliary axis performs a machine function outside coordinated toolpath motion, such as an automatic tool changer. It does not limit coordinated toolpath velocity or acceleration.
Axis calibration establishes units and initial motion values. Those values are starting points, not verified operating limits for the installed machine.
Axis type and calibration setup: Open Document
2.2 Motion Limits
The axis Motion Limits tab is read-only. It shows velocity, acceleration, jerk, and the effective minimum limits across the motors assigned to the axis.
During coordinated motion, MachPro synchronizes the participating axes. Each motor contributes to the effective motion limits; the most restrictive applicable limit can constrain the complete move. Auxiliary axes are excluded.
For Trapezoidal, compare acceleration-rate limits. For PureMotion, compare Constant Acceleration Time and Jerk Time limits. A limiting axis can prevent a coordinated move from benefiting from faster settings on other axes.
Coordinated-motion tests: Open Document
3 Motor Configuration
3.1 Units
Before you start
Calibration sets Units. Incorrect displayed units require a calibration correction. Motors, drives, transmissions, structure, load, lubrication, and mechanical condition determine practical motion limits.
MachPro provides separate limits for:
| Motion type | Function |
|---|---|
| Feed | Commanded machining motion |
| Rapid | Non-cutting positioning |
| Jog | Operator-commanded manual motion |
Velocity and acceleration
Velocity is the maximum commanded axis speed. A move needs sufficient distance to reach it; a high setting does not guarantee that a short move reaches maximum velocity.
Acceleration Entry switches between Units/s² and Time (ms). It changes the displayed and entered representation, not the selected planner.
The actual acceleration settings are defined in the planner comparison. Velocity and acceleration must operate reliably together.
Single-axis tuning and operating margins: Open Document
Coordinated Feed motion
Higher stable acceleration reduces move time for both long and short moves. Short moves can remain below target velocity and still finish sooner with higher acceleration. Feed acceleration can therefore affect cycle time more than maximum Feed Velocity.
For PureMotion, a shorter stable Constant Acceleration Time increases acceleration for the applicable velocity change. Do not lower Feed Velocity solely because short moves do not reach it.
Participating-motor constraints are described in Motion Limits. For tests, use the setup link there.
Rapid and Jog motion
Rapid and Jog have no cutting load, so their reliable limits can differ from Feed limits. Higher Rapid velocity is most useful with sufficient travel; short positioning moves can be acceleration-limited. Jog settings must retain predictable starts, stops, and manual control.
Configuration procedures: Open Document
Motor Units motion graph
The graph shows the commanded profile. It extends the displayed timeline to reach configured maximum velocity, even when an actual move is too short to reach that velocity. It does not predict the time of a specified machine move.
Trapezoidal shows the acceleration-rate profile. PureMotion includes both jerk transitions and its constant-acceleration portion; see PureMotion Jerk Time.
The setup comparison graphics use red for Rapid, green for Feed, velocity vertically, and time horizontally. Matching scales permit direct comparison. Actual speed, move time, and reliability require machine tests; see Final machine test.
Select the motion planner
Trajectory Mode is located at Configure > Control > Defaults. It selects Trapezoidal or PureMotion.
| Characteristic | Trapezoidal | PureMotion |
|---|---|---|
| Planner order | 2nd Order | 3rd Order S-curve |
| Actual acceleration setting | Acceleration rate, units/s² | Constant Acceleration Time, ms |
| Alternate display | Corresponding Time (ms) | Corresponding Units/s² |
| Acceleration transitions | Direct changes between zero and the configured rate | Gradual transitions controlled by Jerk Time |
| Jerk Time | Not used | Separate Feed, Rapid, and Jog settings |
| Acceleration/deceleration | Same setting | Same settings, reversed profile |
| Typical application | Required performance without S-curve smoothing | Smoother transitions improve machine response or stable performance |
For a long Trapezoidal move, the velocity profile has acceleration, constant velocity, and deceleration. A shorter move can have a triangular profile because deceleration starts before maximum velocity is reached.
PureMotion can reduce excitation caused by abrupt acceleration transitions. If both planners meet the application requirements, planner selection is not a primary tuning factor. Neither planner is universally better.
Planner selection and retesting: Open Document
PureMotion Jerk Time
Jerk is the rate of change of acceleration. Jerk Time controls the transitions into and out of constant acceleration and deceleration. Constant Acceleration Time specifies the constant-acceleration portion.
The complete acceleration profile is:
Jerk transition → Constant Acceleration Time → Jerk transition
Total acceleration time = Constant Acceleration Time + (2 × Jerk Time)
For example, 250 ms of Constant Acceleration Time and 25 ms of Jerk Time give 300 ms total. Deceleration uses the reversed profile, with no separate acceleration/deceleration settings.
A shorter Constant Acceleration Time produces a higher acceleration rate for the applicable velocity change. A longer value produces a lower rate. Increasing Jerk Time makes transitions more gradual; 0 ms removes smoothing for that motion type.
PureMotion does not directly tune a vibration frequency. Jerk Time changes acceleration transitions that can excite vibration. Constant Acceleration Time affects acceleration rate, which can also excite mechanical resonance.
Longer transitions can increase move time. If smoothing permits higher stable velocity or acceleration, overall cycle time can decrease. Evaluate the complete machine cycle.
The M31 setup manual gives 10 ms as an initial tuning value and describes 50 ms as high. These are tuning guidance, not a factory default or a permitted maximum.
Jerk-time tuning: Open Document
Copy settings to other motors
Copied values are starting points unless equivalent operating limits have been verified. The copy-control procedure is in Motor Units setup: Open Document
3.2 Final machine test
Accept settings when representative production motion meets position accuracy, drive stability, machining quality, and cycle-time requirements without position loss, faults, excessive vibration, or mechanical instability.
Air cutting establishes initial settings; representative cutting establishes final Feed limits. Machine response can change with travel position, direction, axis combination, tooling, workholding, and load. Significant changes require renewed verification.
Final testing and limiting-axis diagnosis: Open Document
4 Advanced Options and Information
4.1 Path blending and exact stop
Acceleration-profile selection, path blending, exact-stop behavior, and path tolerance are different functions. The available M31 material does not define their complete interaction. See Unresolved questions before adding planner-specific claims.
4.2 Look-ahead and special motion
Short-move acceleration behavior is described in Coordinated Feed motion. It does not establish MachPro's look-ahead depth or queue behavior, or the selected planner's behavior during probing, threading, tapping, and synchronized spindle motion. These remain unresolved.
5 Reference Information
5.1 Parameter locations and definitions
| Setting | Location or owner | Definition |
|---|---|---|
| Trajectory Mode | Configure > Control > Defaults | Planner selection |
| Units | Axis calibration; displayed in Motor Units | Axis calibration |
| Feed, Rapid, Jog Velocity | Motor Units | Velocity and motion types |
| Acceleration Entry | Motor Units | Display/entry representation |
| Trapezoidal acceleration | Motor Units, by motion type | Planner comparison |
| PureMotion Constant Acceleration Time | Motor Units, by motion type | PureMotion profile |
| Feed, Rapid, Jog Jerk Time | Motor Units | PureMotion Jerk Time |
| Effective axis limits | Axis Motion Limits, read-only | Motion Limits |
==Collect factory defaults, permitted ranges, increments, storage scope, controller restrictions, and when each parameter change takes effect. The tuning values above do not supply these specifications.==
5.2 Unresolved questions
| Topic | Information to confirm |
|---|---|
| Software/controller responsibility | ==Which trajectory calculations run in MachPro and which run in the M31? Confirm equivalent behavior on supported non-M31 controllers.== |
| Planner scope and switching | ==Confirm profile/global scope, the G-codes that switch planners, their scope and persistence, and whether any configuration changes require a restart. The draft says G-code can change planners, but supplies no commands.== |
| Coordinated geometry | ==Confirm mixed linear/rotary feed interpretation and effective-limit calculation. Add projection mathematics only if needed to explain configuration or diagnosis.== |
| PureMotion profile | ==Confirm constant jerk during transitions and how short moves truncate or scale the configured time periods.== |
| Jog and stopping | ==Confirm Jog profile behavior and the deceleration/queue behavior used for Feed Hold.== |
| Path control | ==Identify exact-stop and continuous-path G-codes; confirm blending geometry, tolerance, corner velocity, contour error, and whether exact stops use the selected profile.== |
| Look-ahead | ==Confirm support with both planners, algorithm differences, depth, configurability, and commands that synchronize or empty the queue.== |
| Special motion | ==Confirm behavior on arcs, probing, threading, tapping, and synchronized motion.== |
| Filtering | ==Confirm whether filtering modifies the final Trapezoidal output.== |
| Graph scope | ==Confirm Jog display and whether the graph represents individual or coordinated axes.== |
| Diagnostics | ==Identify limiting-axis diagnostics, following-error display, and how to distinguish planner limits from drive limits.== |
| Validation | ==Confirm a standard test program, acceptance criteria for vibration, and guidance for rounded corners, segment pauses, and unequal axis response.== |
| Setup consistency | ==The M31 overview states 80% operating values and 20% margin; its detailed procedures state 80–90% and 10–20%. Confirm the intended guidance and how the acceleration margin is converted to PureMotion time.== |
| Published links | ==Confirm that the published M31 page contains the working manual's HTML anchor IDs. The private page was unavailable for verification.== |
6 Troubleshooting
6.1 Vibration or oscillation
Vibration can indicate excessive motion demand, abrupt transitions, mechanical defects, resonance, drive instability, or cutting-condition problems. Definitions and physical effects are in Mechanical response.
PureMotion addresses acceleration-transition excitation; it does not correct every cause of chatter. Cutting-only vibration can originate in tooling, workholding, spindle condition, or cutting parameters.
Diagnostic steps: Open Document
6.2 Programmed feed is not reached
Possible constraints include move length, acceleration, participating-motor limits, direction changes, and path control. A short move can end before programmed feed is reached. See Short moves and Motion Limits.
Diagnosis and machine tests: Open Document
6.3 Cycle time increases with PureMotion
See PureMotion Jerk Time for the transition-time/performance tradeoff. The tuning and testing procedures are linked there.
7 Application Notes
7.1 Vibration, oscillation, and mechanical condition
Oscillation is repeated motion about an equilibrium position. Vibration is unwanted oscillatory motion, such as shaking, buzzing, chatter, or ripple.
Mechanical looseness, wear, excessive backlash, poor lubrication, damaged components, and unstable drives can produce vibration that planner tuning cannot correct. Correct known defects before optimizing motion.
Vibration does not change physical inertia or moving mass. For linear motion, force = mass × acceleration. Acceleration and oscillatory motion create reaction forces that can increase structural deflection, drive load, position error, or following error.
Mechanical response also depends on stiffness, load, position, direction, spindle operation, tooling, workholding, and cutting forces. Reduced vibration is one verification result; apply the full acceptance criteria.
7.2 Cutting load and planner choice
Use the distinctions in Rapid and Jog motion, the criteria in Final machine test, and the comparison in Select the motion planner. Select the planner for a measurable application benefit.