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# Grbl v1.1 Jogging
Grbl v1.0e huge beta release. Overrides and new reporting. - Feature: Realtime feed, rapid, and spindle speed overrides. These alter the running machine state within tens of milliseconds! - Feed override: 100%, +/-10%, +/-1% commands with values 1-200% of programmed feed - Rapid override: 100%, 50%, 25% rapid rate commands - Spindle speed override: 100%, +/-10%, +/-1% commands with values 50-200% of programmed speed - Override values have configurable limits and increments in config.h. - Feature: Realtime toggle overrides for spindle stop, flood coolant, and optionally mist coolant - Spindle stop: Enables and disables spindle during a feed hold. Automatically restores last spindles state. - Flood and mist coolant: Immediately toggles coolant state until next toggle or g-code coolant command. - Feature: Jogging mode! Incremental and absolute modes supported. - Grbl accepts jogging-specific commands like $J=X100F50. An axis word and feed rate are required. G20/21 and G90/G91 commands are accepted. - Jog motions can be canceled at any time by a feed hold `!` command. The buffer is automatically flushed. (No resetting required). - Jog motions do not alter the g-code parser state so GUIs don’t have to track what they changed and correct it. - Feature: Laser mode setting. Allows Grbl to execute continuous motions with spindle speed and state changes. - Feature: Significantly improved status reports. Overhauled to cram in more meaningful data and still make it smaller on average. - All available data is now sent by default, but does not appear if it doesn’t change or is not active. - Machine position(MPos) or work position(WPos) is reported but not both at the same time. Instead, the work coordinate offsets (WCO)are sent intermittently whenever it changes or refreshes after 10-30 status reports. Position vectors are easily computed by WPos = MPos - WCO. - All data has changed in some way. Details of changes are in the markdown documents and wiki. - Feature: 16 new realtime commands to control overrides. All in extended-ASCII character space. - While they are not easily typeable and requires a GUI, they can’t be accidentally triggered by some latent character in the g-code program and have tons of room for expansion. - Feature: New substates for HOLD and SAFETY DOOR. A `:x` is appended to the state, where `x` is an integer and indicates a substate. - For example, each integer of a door state describes in what phase the machine is in during parking. Substates are detailed in the documentation. - Feature: With the alarm codes, homing and probe alarms have been expanded with more codes to provide more exact feedback on what caused the alarm. - Feature: New hard limit check upon power-up or reset. If detected, a feedback message to check the limit switches sent immediately after the welcome message. - May be disabled in config.h. - OEM feature: Enable/disable `$RST=` individual commands based on desired behavior in config.h. - OEM feature: Configurable EEPROM wipe to prevent certain data from being deleted during firmware upgrade to a new settings version or `RST=*` command. - OEM feature: Enable/disable the `$I=` build info write string with external EEPROM write example sketch. - This prevents a user from altering the build info string in EEPROM. This requires the vendor to write the string to EEPROM via external means. An Arduino example sketch is provided to accomplish this. This would be useful for contain product data that is retrievable. - Tweak: All feedback has been drastically trimmed to free up flash space for the v1.0 release. - The `$` help message is just one string, listing available commands. - The `$$` settings printout no longer includes descriptions. Only the setting values. (Sorry it’s this or remove overrides!) - Grbl `error:` and `ALARM:` responses now only contain codes. No descriptions. All codes are explained in documentation. - Grbl’s old feedback style may be restored via a config.h, but keep in mind that it will likely not fit into the Arduino’s flash space. - Tweak: Grbl now forces a buffer sync or stop motion whenever a g-code command needs to update and write a value to EEPROM or changes the work coordinate offset. - This addresses two old issues in all prior Grbl versions. First, an EEPROM write requires interrupts to be disabled, including stepper and serial comm. Steps can be lost and data can be corrupted. Second, the work position may not be correlated to the actual machine position, since machine position is derived from the actual current execution state, while work position is based on the g-code parser offset state. They are usually not in sync and the parser state is several motions behind. This forced sync ensures work and machine positions are always correct. - This behavior can be disabled through a config.h option, but it’s not recommended to do so. - Tweak: To make status reports standardized, users can no longer change what is reported via status report mask, except for only toggling machine or work positions. - All other data fields are included in the report and can only be disabled through the config.h file. It’s not recommended to alter this, because GUIs will be expecting this data to be present and may not be compatible. - Tweak: Homing cycle and parking motion no longer report a negative line number in a status report. These will now not report a line number at all. - Tweak: New `[Restoring spindle]` message when restoring from a spindle stop override. Provides feedback what Grbl is doing while the spindle is powering up and a 4.0 second delay is enforced. - Tweak: Override values are reset to 100% upon M2/30. This behavior can be disabled in config.h - Tweak: The planner buffer size has been reduced from 18 to 16 to free up RAM for tracking and controlling overrides. - Tweak: TX buffer size has been increased from 64 to 90 bytes to improve status reporting and overall performance. - Tweak: Removed the MOTION CANCEL state. It was redundant and didn’t affect Grbl’s overall operation by doing so. - Tweak: Grbl’s serial buffer increased by +1 internally, such that 128 bytes means 128, not 127 due to the ring buffer implementation. Long overdue. - Tweak: Altered sys.alarm variable to be set by alarm codes, rather than bit flags. Simplified how it worked overall. - Tweak: Planner buffer and serial RX buffer usage has been combined in the status reports. - Tweak: Pin state reporting has been refactored to report only the pins “triggered” and nothing when not “triggered”. - Tweak: Current machine rate or speed is now included in every report. - Tweak: The work coordinate offset (WCO) and override states only need to be refreshed intermittently or reported when they change. The refresh rates may be altered for each in the config.h file with different idle and busy rates to lessen Grbl’s load during a job. - Tweak: For temporary compatibility to existing GUIs until they are updated, an option to revert back to the old style status reports is available in config.h, but not recommended for long term use. - Tweak: Removed old limit pin state reporting option from config.h in lieu of new status report that includes them. - Tweak: Updated the defaults.h file to include laser mode, altered status report mask, and fix an issue with a missing invert probe pin default. - Refactor: Changed how planner line data is generated and passed to the planner and onto the step generator. By making it a struct variable, this saved significant flash space. - Refactor: Major re-factoring of the planner to incorporate override values and allow for re-calculations fast enough to immediately take effect during operation. No small feat. - Refactor: Re-factored the step segment generator for re-computing new override states. - Refactor: Re-factored spindle_control.c to accommodate the spindle speed overrides and laser mode. - Refactor: Re-factored parts of the codebase for a new jogging mode. Still under development though and slated to be part of the official v1.0 release. Hang tight. - Refactor: Created functions for computing a unit vector and value limiting based on axis maximums to free up more flash. - Refactor: The spindle PWM is now set directly inside of the stepper ISR as it loads new step segments. - Refactor: Moved machine travel checks out of soft limits function into its own since jogging uses this too. - Refactor: Removed coolant_stop() and combined with coolant_set_state(). - Refactor: The serial RX ISR forks off extended ASCII values to quickly assess the new override realtime commands. - Refactor: Altered some names of the step control flags. - Refactor: Improved efficiency of the serial RX get buffer count function. - Refactor: Saved significant flash by removing and combining print functions. Namely the uint8 base10 and base2 functions. - Refactor: Moved the probe state check in the main stepper ISR to improve its efficiency. - Refactor: Single character printPgmStrings() went converted to direct serial_write() commands to save significant flash space. - Documentation: Detailed Markdown documents on error codes, alarm codes, messages, new real-time commands, new status reports, and how jogging works. More to come later and will be posted on the Wiki as well. - Documentation: CSV files for quick importing of Grbl error and alarm codes. - Bug Fix: Applied v0.9 master fixes to CoreXY homing. - Bug Fix: The print float function would cause Grbl to crash if a value was 1e6 or greater. Increased the buffer by 3 bytes to help prevent this in the future. - Bug Fix: Build info and startup string EEPROM restoring was not writing the checksum value. - Bug Fix: Corrected an issue with safety door restoring the proper spindle and coolant state. It worked before, but breaks with laser mode that can continually change spindle state per planner block. - Bug Fix: Move system position and probe position arrays out of the system_t struct. Ran into some compiling errors that were hard to track down as to why. Moving them out fixed it.
2016-09-22 03:08:24 +02:00
## How to Use
Grbl v1.0e huge beta release. Overrides and new reporting. - Feature: Realtime feed, rapid, and spindle speed overrides. These alter the running machine state within tens of milliseconds! - Feed override: 100%, +/-10%, +/-1% commands with values 1-200% of programmed feed - Rapid override: 100%, 50%, 25% rapid rate commands - Spindle speed override: 100%, +/-10%, +/-1% commands with values 50-200% of programmed speed - Override values have configurable limits and increments in config.h. - Feature: Realtime toggle overrides for spindle stop, flood coolant, and optionally mist coolant - Spindle stop: Enables and disables spindle during a feed hold. Automatically restores last spindles state. - Flood and mist coolant: Immediately toggles coolant state until next toggle or g-code coolant command. - Feature: Jogging mode! Incremental and absolute modes supported. - Grbl accepts jogging-specific commands like $J=X100F50. An axis word and feed rate are required. G20/21 and G90/G91 commands are accepted. - Jog motions can be canceled at any time by a feed hold `!` command. The buffer is automatically flushed. (No resetting required). - Jog motions do not alter the g-code parser state so GUIs don’t have to track what they changed and correct it. - Feature: Laser mode setting. Allows Grbl to execute continuous motions with spindle speed and state changes. - Feature: Significantly improved status reports. Overhauled to cram in more meaningful data and still make it smaller on average. - All available data is now sent by default, but does not appear if it doesn’t change or is not active. - Machine position(MPos) or work position(WPos) is reported but not both at the same time. Instead, the work coordinate offsets (WCO)are sent intermittently whenever it changes or refreshes after 10-30 status reports. Position vectors are easily computed by WPos = MPos - WCO. - All data has changed in some way. Details of changes are in the markdown documents and wiki. - Feature: 16 new realtime commands to control overrides. All in extended-ASCII character space. - While they are not easily typeable and requires a GUI, they can’t be accidentally triggered by some latent character in the g-code program and have tons of room for expansion. - Feature: New substates for HOLD and SAFETY DOOR. A `:x` is appended to the state, where `x` is an integer and indicates a substate. - For example, each integer of a door state describes in what phase the machine is in during parking. Substates are detailed in the documentation. - Feature: With the alarm codes, homing and probe alarms have been expanded with more codes to provide more exact feedback on what caused the alarm. - Feature: New hard limit check upon power-up or reset. If detected, a feedback message to check the limit switches sent immediately after the welcome message. - May be disabled in config.h. - OEM feature: Enable/disable `$RST=` individual commands based on desired behavior in config.h. - OEM feature: Configurable EEPROM wipe to prevent certain data from being deleted during firmware upgrade to a new settings version or `RST=*` command. - OEM feature: Enable/disable the `$I=` build info write string with external EEPROM write example sketch. - This prevents a user from altering the build info string in EEPROM. This requires the vendor to write the string to EEPROM via external means. An Arduino example sketch is provided to accomplish this. This would be useful for contain product data that is retrievable. - Tweak: All feedback has been drastically trimmed to free up flash space for the v1.0 release. - The `$` help message is just one string, listing available commands. - The `$$` settings printout no longer includes descriptions. Only the setting values. (Sorry it’s this or remove overrides!) - Grbl `error:` and `ALARM:` responses now only contain codes. No descriptions. All codes are explained in documentation. - Grbl’s old feedback style may be restored via a config.h, but keep in mind that it will likely not fit into the Arduino’s flash space. - Tweak: Grbl now forces a buffer sync or stop motion whenever a g-code command needs to update and write a value to EEPROM or changes the work coordinate offset. - This addresses two old issues in all prior Grbl versions. First, an EEPROM write requires interrupts to be disabled, including stepper and serial comm. Steps can be lost and data can be corrupted. Second, the work position may not be correlated to the actual machine position, since machine position is derived from the actual current execution state, while work position is based on the g-code parser offset state. They are usually not in sync and the parser state is several motions behind. This forced sync ensures work and machine positions are always correct. - This behavior can be disabled through a config.h option, but it’s not recommended to do so. - Tweak: To make status reports standardized, users can no longer change what is reported via status report mask, except for only toggling machine or work positions. - All other data fields are included in the report and can only be disabled through the config.h file. It’s not recommended to alter this, because GUIs will be expecting this data to be present and may not be compatible. - Tweak: Homing cycle and parking motion no longer report a negative line number in a status report. These will now not report a line number at all. - Tweak: New `[Restoring spindle]` message when restoring from a spindle stop override. Provides feedback what Grbl is doing while the spindle is powering up and a 4.0 second delay is enforced. - Tweak: Override values are reset to 100% upon M2/30. This behavior can be disabled in config.h - Tweak: The planner buffer size has been reduced from 18 to 16 to free up RAM for tracking and controlling overrides. - Tweak: TX buffer size has been increased from 64 to 90 bytes to improve status reporting and overall performance. - Tweak: Removed the MOTION CANCEL state. It was redundant and didn’t affect Grbl’s overall operation by doing so. - Tweak: Grbl’s serial buffer increased by +1 internally, such that 128 bytes means 128, not 127 due to the ring buffer implementation. Long overdue. - Tweak: Altered sys.alarm variable to be set by alarm codes, rather than bit flags. Simplified how it worked overall. - Tweak: Planner buffer and serial RX buffer usage has been combined in the status reports. - Tweak: Pin state reporting has been refactored to report only the pins “triggered” and nothing when not “triggered”. - Tweak: Current machine rate or speed is now included in every report. - Tweak: The work coordinate offset (WCO) and override states only need to be refreshed intermittently or reported when they change. The refresh rates may be altered for each in the config.h file with different idle and busy rates to lessen Grbl’s load during a job. - Tweak: For temporary compatibility to existing GUIs until they are updated, an option to revert back to the old style status reports is available in config.h, but not recommended for long term use. - Tweak: Removed old limit pin state reporting option from config.h in lieu of new status report that includes them. - Tweak: Updated the defaults.h file to include laser mode, altered status report mask, and fix an issue with a missing invert probe pin default. - Refactor: Changed how planner line data is generated and passed to the planner and onto the step generator. By making it a struct variable, this saved significant flash space. - Refactor: Major re-factoring of the planner to incorporate override values and allow for re-calculations fast enough to immediately take effect during operation. No small feat. - Refactor: Re-factored the step segment generator for re-computing new override states. - Refactor: Re-factored spindle_control.c to accommodate the spindle speed overrides and laser mode. - Refactor: Re-factored parts of the codebase for a new jogging mode. Still under development though and slated to be part of the official v1.0 release. Hang tight. - Refactor: Created functions for computing a unit vector and value limiting based on axis maximums to free up more flash. - Refactor: The spindle PWM is now set directly inside of the stepper ISR as it loads new step segments. - Refactor: Moved machine travel checks out of soft limits function into its own since jogging uses this too. - Refactor: Removed coolant_stop() and combined with coolant_set_state(). - Refactor: The serial RX ISR forks off extended ASCII values to quickly assess the new override realtime commands. - Refactor: Altered some names of the step control flags. - Refactor: Improved efficiency of the serial RX get buffer count function. - Refactor: Saved significant flash by removing and combining print functions. Namely the uint8 base10 and base2 functions. - Refactor: Moved the probe state check in the main stepper ISR to improve its efficiency. - Refactor: Single character printPgmStrings() went converted to direct serial_write() commands to save significant flash space. - Documentation: Detailed Markdown documents on error codes, alarm codes, messages, new real-time commands, new status reports, and how jogging works. More to come later and will be posted on the Wiki as well. - Documentation: CSV files for quick importing of Grbl error and alarm codes. - Bug Fix: Applied v0.9 master fixes to CoreXY homing. - Bug Fix: The print float function would cause Grbl to crash if a value was 1e6 or greater. Increased the buffer by 3 bytes to help prevent this in the future. - Bug Fix: Build info and startup string EEPROM restoring was not writing the checksum value. - Bug Fix: Corrected an issue with safety door restoring the proper spindle and coolant state. It worked before, but breaks with laser mode that can continually change spindle state per planner block. - Bug Fix: Move system position and probe position arrays out of the system_t struct. Ran into some compiling errors that were hard to track down as to why. Moving them out fixed it.
2016-09-22 03:08:24 +02:00
Executing a jog requires a specific command structure, as described below:
- The first three characters must be '$J=' to indicate the jog.
- The jog command follows immediate after the '=' and works like a normal G1 command.
- Feed rate is only interpreted in G94 units per minute. A prior G93 state is ignored during jog.
- Required words:
- XYZ: One or more axis words with target value.
- F - Feed rate value. NOTE: Each jog requires this value and is not treated as modal.
- Optional words: Jog executes based on current G20/G21 and G90/G91 g-code parser state. If one of the following optional words is passed, that state is overridden for one command only.
Grbl v1.0e huge beta release. Overrides and new reporting. - Feature: Realtime feed, rapid, and spindle speed overrides. These alter the running machine state within tens of milliseconds! - Feed override: 100%, +/-10%, +/-1% commands with values 1-200% of programmed feed - Rapid override: 100%, 50%, 25% rapid rate commands - Spindle speed override: 100%, +/-10%, +/-1% commands with values 50-200% of programmed speed - Override values have configurable limits and increments in config.h. - Feature: Realtime toggle overrides for spindle stop, flood coolant, and optionally mist coolant - Spindle stop: Enables and disables spindle during a feed hold. Automatically restores last spindles state. - Flood and mist coolant: Immediately toggles coolant state until next toggle or g-code coolant command. - Feature: Jogging mode! Incremental and absolute modes supported. - Grbl accepts jogging-specific commands like $J=X100F50. An axis word and feed rate are required. G20/21 and G90/G91 commands are accepted. - Jog motions can be canceled at any time by a feed hold `!` command. The buffer is automatically flushed. (No resetting required). - Jog motions do not alter the g-code parser state so GUIs don’t have to track what they changed and correct it. - Feature: Laser mode setting. Allows Grbl to execute continuous motions with spindle speed and state changes. - Feature: Significantly improved status reports. Overhauled to cram in more meaningful data and still make it smaller on average. - All available data is now sent by default, but does not appear if it doesn’t change or is not active. - Machine position(MPos) or work position(WPos) is reported but not both at the same time. Instead, the work coordinate offsets (WCO)are sent intermittently whenever it changes or refreshes after 10-30 status reports. Position vectors are easily computed by WPos = MPos - WCO. - All data has changed in some way. Details of changes are in the markdown documents and wiki. - Feature: 16 new realtime commands to control overrides. All in extended-ASCII character space. - While they are not easily typeable and requires a GUI, they can’t be accidentally triggered by some latent character in the g-code program and have tons of room for expansion. - Feature: New substates for HOLD and SAFETY DOOR. A `:x` is appended to the state, where `x` is an integer and indicates a substate. - For example, each integer of a door state describes in what phase the machine is in during parking. Substates are detailed in the documentation. - Feature: With the alarm codes, homing and probe alarms have been expanded with more codes to provide more exact feedback on what caused the alarm. - Feature: New hard limit check upon power-up or reset. If detected, a feedback message to check the limit switches sent immediately after the welcome message. - May be disabled in config.h. - OEM feature: Enable/disable `$RST=` individual commands based on desired behavior in config.h. - OEM feature: Configurable EEPROM wipe to prevent certain data from being deleted during firmware upgrade to a new settings version or `RST=*` command. - OEM feature: Enable/disable the `$I=` build info write string with external EEPROM write example sketch. - This prevents a user from altering the build info string in EEPROM. This requires the vendor to write the string to EEPROM via external means. An Arduino example sketch is provided to accomplish this. This would be useful for contain product data that is retrievable. - Tweak: All feedback has been drastically trimmed to free up flash space for the v1.0 release. - The `$` help message is just one string, listing available commands. - The `$$` settings printout no longer includes descriptions. Only the setting values. (Sorry it’s this or remove overrides!) - Grbl `error:` and `ALARM:` responses now only contain codes. No descriptions. All codes are explained in documentation. - Grbl’s old feedback style may be restored via a config.h, but keep in mind that it will likely not fit into the Arduino’s flash space. - Tweak: Grbl now forces a buffer sync or stop motion whenever a g-code command needs to update and write a value to EEPROM or changes the work coordinate offset. - This addresses two old issues in all prior Grbl versions. First, an EEPROM write requires interrupts to be disabled, including stepper and serial comm. Steps can be lost and data can be corrupted. Second, the work position may not be correlated to the actual machine position, since machine position is derived from the actual current execution state, while work position is based on the g-code parser offset state. They are usually not in sync and the parser state is several motions behind. This forced sync ensures work and machine positions are always correct. - This behavior can be disabled through a config.h option, but it’s not recommended to do so. - Tweak: To make status reports standardized, users can no longer change what is reported via status report mask, except for only toggling machine or work positions. - All other data fields are included in the report and can only be disabled through the config.h file. It’s not recommended to alter this, because GUIs will be expecting this data to be present and may not be compatible. - Tweak: Homing cycle and parking motion no longer report a negative line number in a status report. These will now not report a line number at all. - Tweak: New `[Restoring spindle]` message when restoring from a spindle stop override. Provides feedback what Grbl is doing while the spindle is powering up and a 4.0 second delay is enforced. - Tweak: Override values are reset to 100% upon M2/30. This behavior can be disabled in config.h - Tweak: The planner buffer size has been reduced from 18 to 16 to free up RAM for tracking and controlling overrides. - Tweak: TX buffer size has been increased from 64 to 90 bytes to improve status reporting and overall performance. - Tweak: Removed the MOTION CANCEL state. It was redundant and didn’t affect Grbl’s overall operation by doing so. - Tweak: Grbl’s serial buffer increased by +1 internally, such that 128 bytes means 128, not 127 due to the ring buffer implementation. Long overdue. - Tweak: Altered sys.alarm variable to be set by alarm codes, rather than bit flags. Simplified how it worked overall. - Tweak: Planner buffer and serial RX buffer usage has been combined in the status reports. - Tweak: Pin state reporting has been refactored to report only the pins “triggered” and nothing when not “triggered”. - Tweak: Current machine rate or speed is now included in every report. - Tweak: The work coordinate offset (WCO) and override states only need to be refreshed intermittently or reported when they change. The refresh rates may be altered for each in the config.h file with different idle and busy rates to lessen Grbl’s load during a job. - Tweak: For temporary compatibility to existing GUIs until they are updated, an option to revert back to the old style status reports is available in config.h, but not recommended for long term use. - Tweak: Removed old limit pin state reporting option from config.h in lieu of new status report that includes them. - Tweak: Updated the defaults.h file to include laser mode, altered status report mask, and fix an issue with a missing invert probe pin default. - Refactor: Changed how planner line data is generated and passed to the planner and onto the step generator. By making it a struct variable, this saved significant flash space. - Refactor: Major re-factoring of the planner to incorporate override values and allow for re-calculations fast enough to immediately take effect during operation. No small feat. - Refactor: Re-factored the step segment generator for re-computing new override states. - Refactor: Re-factored spindle_control.c to accommodate the spindle speed overrides and laser mode. - Refactor: Re-factored parts of the codebase for a new jogging mode. Still under development though and slated to be part of the official v1.0 release. Hang tight. - Refactor: Created functions for computing a unit vector and value limiting based on axis maximums to free up more flash. - Refactor: The spindle PWM is now set directly inside of the stepper ISR as it loads new step segments. - Refactor: Moved machine travel checks out of soft limits function into its own since jogging uses this too. - Refactor: Removed coolant_stop() and combined with coolant_set_state(). - Refactor: The serial RX ISR forks off extended ASCII values to quickly assess the new override realtime commands. - Refactor: Altered some names of the step control flags. - Refactor: Improved efficiency of the serial RX get buffer count function. - Refactor: Saved significant flash by removing and combining print functions. Namely the uint8 base10 and base2 functions. - Refactor: Moved the probe state check in the main stepper ISR to improve its efficiency. - Refactor: Single character printPgmStrings() went converted to direct serial_write() commands to save significant flash space. - Documentation: Detailed Markdown documents on error codes, alarm codes, messages, new real-time commands, new status reports, and how jogging works. More to come later and will be posted on the Wiki as well. - Documentation: CSV files for quick importing of Grbl error and alarm codes. - Bug Fix: Applied v0.9 master fixes to CoreXY homing. - Bug Fix: The print float function would cause Grbl to crash if a value was 1e6 or greater. Increased the buffer by 3 bytes to help prevent this in the future. - Bug Fix: Build info and startup string EEPROM restoring was not writing the checksum value. - Bug Fix: Corrected an issue with safety door restoring the proper spindle and coolant state. It worked before, but breaks with laser mode that can continually change spindle state per planner block. - Bug Fix: Move system position and probe position arrays out of the system_t struct. Ran into some compiling errors that were hard to track down as to why. Moving them out fixed it.
2016-09-22 03:08:24 +02:00
- G20 or G21 - Inch and millimeter mode
- G90 or G91 - Absolute and incremental distances
- G53 - Move in machine coordinates
- All other g-codes, m-codes, and value words are not accepted in the jog command.
- Spaces and comments are allowed in the command. These are removed by the pre-parser.
- Example: G21 and G90 are active modal states prior to jogging. These are sequential commands.
- `$J=X10.0 Y-1.5` will move to X=10.0mm and Y=-1.5mm in work coordinate frame (WPos).
- `$J=G91 G20 X0.5` will move +0.5 inches (12.7mm) to X=22.7mm (WPos). Note that G91 and G20 are only applied to this jog command.
- `$J=G53 Y5.0` will move the machine to Y=5.0mm in the machine coordinate frame (MPos). If the work coordinate offset for the y-axis is 2.0mm, then Y is 3.0mm in (WPos).
Jog commands behave almost identically to normal g-code streaming. Every jog command will
return an 'ok' when the jogging motion has been parsed and is setup for execution. If a
command is not valid, Grbl will return an 'error:'. Multiple jogging commands may be
queued in sequence.
The main differences are:
Grbl v1.0e huge beta release. Overrides and new reporting. - Feature: Realtime feed, rapid, and spindle speed overrides. These alter the running machine state within tens of milliseconds! - Feed override: 100%, +/-10%, +/-1% commands with values 1-200% of programmed feed - Rapid override: 100%, 50%, 25% rapid rate commands - Spindle speed override: 100%, +/-10%, +/-1% commands with values 50-200% of programmed speed - Override values have configurable limits and increments in config.h. - Feature: Realtime toggle overrides for spindle stop, flood coolant, and optionally mist coolant - Spindle stop: Enables and disables spindle during a feed hold. Automatically restores last spindles state. - Flood and mist coolant: Immediately toggles coolant state until next toggle or g-code coolant command. - Feature: Jogging mode! Incremental and absolute modes supported. - Grbl accepts jogging-specific commands like $J=X100F50. An axis word and feed rate are required. G20/21 and G90/G91 commands are accepted. - Jog motions can be canceled at any time by a feed hold `!` command. The buffer is automatically flushed. (No resetting required). - Jog motions do not alter the g-code parser state so GUIs don’t have to track what they changed and correct it. - Feature: Laser mode setting. Allows Grbl to execute continuous motions with spindle speed and state changes. - Feature: Significantly improved status reports. Overhauled to cram in more meaningful data and still make it smaller on average. - All available data is now sent by default, but does not appear if it doesn’t change or is not active. - Machine position(MPos) or work position(WPos) is reported but not both at the same time. Instead, the work coordinate offsets (WCO)are sent intermittently whenever it changes or refreshes after 10-30 status reports. Position vectors are easily computed by WPos = MPos - WCO. - All data has changed in some way. Details of changes are in the markdown documents and wiki. - Feature: 16 new realtime commands to control overrides. All in extended-ASCII character space. - While they are not easily typeable and requires a GUI, they can’t be accidentally triggered by some latent character in the g-code program and have tons of room for expansion. - Feature: New substates for HOLD and SAFETY DOOR. A `:x` is appended to the state, where `x` is an integer and indicates a substate. - For example, each integer of a door state describes in what phase the machine is in during parking. Substates are detailed in the documentation. - Feature: With the alarm codes, homing and probe alarms have been expanded with more codes to provide more exact feedback on what caused the alarm. - Feature: New hard limit check upon power-up or reset. If detected, a feedback message to check the limit switches sent immediately after the welcome message. - May be disabled in config.h. - OEM feature: Enable/disable `$RST=` individual commands based on desired behavior in config.h. - OEM feature: Configurable EEPROM wipe to prevent certain data from being deleted during firmware upgrade to a new settings version or `RST=*` command. - OEM feature: Enable/disable the `$I=` build info write string with external EEPROM write example sketch. - This prevents a user from altering the build info string in EEPROM. This requires the vendor to write the string to EEPROM via external means. An Arduino example sketch is provided to accomplish this. This would be useful for contain product data that is retrievable. - Tweak: All feedback has been drastically trimmed to free up flash space for the v1.0 release. - The `$` help message is just one string, listing available commands. - The `$$` settings printout no longer includes descriptions. Only the setting values. (Sorry it’s this or remove overrides!) - Grbl `error:` and `ALARM:` responses now only contain codes. No descriptions. All codes are explained in documentation. - Grbl’s old feedback style may be restored via a config.h, but keep in mind that it will likely not fit into the Arduino’s flash space. - Tweak: Grbl now forces a buffer sync or stop motion whenever a g-code command needs to update and write a value to EEPROM or changes the work coordinate offset. - This addresses two old issues in all prior Grbl versions. First, an EEPROM write requires interrupts to be disabled, including stepper and serial comm. Steps can be lost and data can be corrupted. Second, the work position may not be correlated to the actual machine position, since machine position is derived from the actual current execution state, while work position is based on the g-code parser offset state. They are usually not in sync and the parser state is several motions behind. This forced sync ensures work and machine positions are always correct. - This behavior can be disabled through a config.h option, but it’s not recommended to do so. - Tweak: To make status reports standardized, users can no longer change what is reported via status report mask, except for only toggling machine or work positions. - All other data fields are included in the report and can only be disabled through the config.h file. It’s not recommended to alter this, because GUIs will be expecting this data to be present and may not be compatible. - Tweak: Homing cycle and parking motion no longer report a negative line number in a status report. These will now not report a line number at all. - Tweak: New `[Restoring spindle]` message when restoring from a spindle stop override. Provides feedback what Grbl is doing while the spindle is powering up and a 4.0 second delay is enforced. - Tweak: Override values are reset to 100% upon M2/30. This behavior can be disabled in config.h - Tweak: The planner buffer size has been reduced from 18 to 16 to free up RAM for tracking and controlling overrides. - Tweak: TX buffer size has been increased from 64 to 90 bytes to improve status reporting and overall performance. - Tweak: Removed the MOTION CANCEL state. It was redundant and didn’t affect Grbl’s overall operation by doing so. - Tweak: Grbl’s serial buffer increased by +1 internally, such that 128 bytes means 128, not 127 due to the ring buffer implementation. Long overdue. - Tweak: Altered sys.alarm variable to be set by alarm codes, rather than bit flags. Simplified how it worked overall. - Tweak: Planner buffer and serial RX buffer usage has been combined in the status reports. - Tweak: Pin state reporting has been refactored to report only the pins “triggered” and nothing when not “triggered”. - Tweak: Current machine rate or speed is now included in every report. - Tweak: The work coordinate offset (WCO) and override states only need to be refreshed intermittently or reported when they change. The refresh rates may be altered for each in the config.h file with different idle and busy rates to lessen Grbl’s load during a job. - Tweak: For temporary compatibility to existing GUIs until they are updated, an option to revert back to the old style status reports is available in config.h, but not recommended for long term use. - Tweak: Removed old limit pin state reporting option from config.h in lieu of new status report that includes them. - Tweak: Updated the defaults.h file to include laser mode, altered status report mask, and fix an issue with a missing invert probe pin default. - Refactor: Changed how planner line data is generated and passed to the planner and onto the step generator. By making it a struct variable, this saved significant flash space. - Refactor: Major re-factoring of the planner to incorporate override values and allow for re-calculations fast enough to immediately take effect during operation. No small feat. - Refactor: Re-factored the step segment generator for re-computing new override states. - Refactor: Re-factored spindle_control.c to accommodate the spindle speed overrides and laser mode. - Refactor: Re-factored parts of the codebase for a new jogging mode. Still under development though and slated to be part of the official v1.0 release. Hang tight. - Refactor: Created functions for computing a unit vector and value limiting based on axis maximums to free up more flash. - Refactor: The spindle PWM is now set directly inside of the stepper ISR as it loads new step segments. - Refactor: Moved machine travel checks out of soft limits function into its own since jogging uses this too. - Refactor: Removed coolant_stop() and combined with coolant_set_state(). - Refactor: The serial RX ISR forks off extended ASCII values to quickly assess the new override realtime commands. - Refactor: Altered some names of the step control flags. - Refactor: Improved efficiency of the serial RX get buffer count function. - Refactor: Saved significant flash by removing and combining print functions. Namely the uint8 base10 and base2 functions. - Refactor: Moved the probe state check in the main stepper ISR to improve its efficiency. - Refactor: Single character printPgmStrings() went converted to direct serial_write() commands to save significant flash space. - Documentation: Detailed Markdown documents on error codes, alarm codes, messages, new real-time commands, new status reports, and how jogging works. More to come later and will be posted on the Wiki as well. - Documentation: CSV files for quick importing of Grbl error and alarm codes. - Bug Fix: Applied v0.9 master fixes to CoreXY homing. - Bug Fix: The print float function would cause Grbl to crash if a value was 1e6 or greater. Increased the buffer by 3 bytes to help prevent this in the future. - Bug Fix: Build info and startup string EEPROM restoring was not writing the checksum value. - Bug Fix: Corrected an issue with safety door restoring the proper spindle and coolant state. It worked before, but breaks with laser mode that can continually change spindle state per planner block. - Bug Fix: Move system position and probe position arrays out of the system_t struct. Ran into some compiling errors that were hard to track down as to why. Moving them out fixed it.
2016-09-22 03:08:24 +02:00
- During a jog, Grbl will report a 'Jog' state while executing the jog.
- A jog command will only be accepted when Grbl is in either the 'Idle' or 'Jog' states.
- Jogging motions may not be mixed with g-code commands while executing, which will return a lockout error, if attempted.
- All jogging motion(s) may be cancelled at anytime with a simple jog cancel realtime command or a feed hold or safety door event. Grbl will automatically flush Grbl's internal buffers of any queued jogging motions and return to the 'Idle' state. No soft-reset required.
- If soft-limits are enabled, jog commands that exceed the machine travel simply does not execute the command and return an error, rather than throwing an alarm in normal operation.
- IMPORTANT: Jogging does not alter the g-code parser state. Hence, no g-code modes need to be explicitly managed, unlike previous ways of implementing jogs with commands like 'G91G1X1F100'. Since G91, G1, and F feed rates are modal and if they are not changed back prior to resuming/starting a job, a job may not run how its was intended and result in a crash.
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## Joystick Implementation
Jogging in Grbl v1.1 is generally intended to address some prior issues with old bootstrapped jogging methods. Unfortunately, the new Grbl jogging is not a complete solution. Flash and memory restrictions prevent the original envisioned implementation, but most of these can be mimicked by the following suggested methodology.
With a combination of the new jog cancel and moving in `G91` incremental mode, the following implementation can create low latency feel for an analog joystick or similar control device.
- Basic Implementation Overview:
- Create a loop to read the joystick signal and translate it to a desired jog motion vector.
- Send Grbl a very short `G91` incremental distance jog command with a feed rate based on the joystick throw.
- Wait for an 'ok' acknowledgement before restarting the loop.
- Continually read the joystick input and send Grbl short jog motions to keep Grbl's planner buffer full.
- If the joystick is returned to its neutral position, stop the jog loop and simply send Grbl a jog cancel real-time command. This will stop motion immediately somewhere along the programmed jog path with virtually zero-latency and automatically flush Grbl's planner queue. It's not advised to use a feed hold to cancel a jog, as it can lead to inadvertently suspending Grbl if its sent after returning to the IDLE state.
The overall idea is to minimize the total distance in the planner queue to provide a low-latency feel to joystick control. The main trick is ensuring there is just enough distance in the planner queue, such that the programmed feed rate is always met. How to compute this will be explain later. In practice, most machines will have a 0.5-1.0 second latency. When combined with the immediate jog cancel command, joystick interaction can be quite enjoyable and satisfying.
However, please note, if a machine has a low acceleration and is being asked to move at a high programmed feed rate, joystick latency can get up to a handful of seconds. It may sound bad, but this is how long it'll take for a low acceleration machine, traveling at a high feed rate, to slow down to a stop. The argument can be made for a low acceleration machine that you really shouldn't be jogging at a high feed rate. It is difficult for a user to gauge where the machine will come to a stop. You risk overshooting your target destination, which can result in an expensive or dangerous crash.
One of the advantages of this approach is that a GUI can deterministically track where Grbl will go by the jog commands it has already sent to Grbl. As long as a jog isn't cancelled, every jog command is guaranteed to execute. In the event a jog cancel is invoked, the GUI would just need to refresh their internal position from a status report after Grbl has cleared planner buffer and returned to the IDLE (or DOOR, if ajar) state from the JOG state. This stopped position will always be somewhere along the programmed jog path. If desired, jogging can then be quickly and easily restarted with a new tracked path.
In combination with `G53` move in machine coordinates, a GUI can restrict jogging from moving into "keep-out" zones inside the machine space. This can be very useful for avoiding crashing into delicate probing hardware, workholding mechanisms, or other fixed features inside machine space that you want to avoid.
#### How to compute incremental distances
The quickest and easiest way to determine what the length of a jog motion needs to be to minimize latency are defined by the following equations.
`s = v * dt` - Computes distance traveled for next jog command.
where:
- `s` - Incremental distance of jog command.
- `dt` - Estimated execution time of a single jog command in seconds.
- `v` - Current jog feed rate in **mm/sec**, not mm/min. Less than or equal to max jog rate.
- `N` - Number of Grbl planner blocks (`N=15`)
- `T = dt * N` - Computes total estimated latency in seconds.
The time increment `dt` may be defined to whatever value you need. Obviously, you'd like the lowest value, since that translates to lower overall latency `T`. However, it is constrained by two factors.
- `dt > 10ms` - The time it takes Grbl to parse and plan one jog command and receive the next one. Depending on a lot of factors, this can be around 1 to 5 ms. To be conservative, `10ms` is used. Keep in mind that on some systems, this value may still be greater than `10ms` due to round-trip communication latency.
- `dt > v^2 / (2 * a * (N-1))` - The time increment needs to be large enough to ensure the jog feed rate will be acheived. Grbl always plans to a stop over the total distance queued in the planner buffer. This is primarily to ensure the machine will safely stop if a disconnection occurs. This equation simply ensures that `dt` is big enough to satisfy this constraint.
- For simplicity, use the max jog feed rate for `v` in mm/sec and the smallest acceleration setting between the jog axes being moved in mm/sec^2.
- For a lower latency, `dt` can be computed for each jog motion, where `v` is the current rate and `a` is the max acceleration along the jog vector. This is very useful if traveling a very slow speeds to locate a part zero. The `v` rate would be much lower in this scenario and the total latency would decrease quadratically.
In practice, most CNC machines will operate with a jogging time increment of `0.025 sec` < `dt` < `0.06 sec`, which translates to about a `0.4` to `0.9` second total latency when traveling at the max jog rate. Good enough for most people.
However, if jogging at a slower speed and a GUI adjusts the `dt` with it, you can get very close to the 0.1 second response time by human-interface guidelines for "feeling instantaneous". Not too shabby!
With some ingenuity, this jogging methodology may be applied to different devices such as a rotary dial or touchscreen. An "inertial-feel", like swipe-scrolling on a smartphone or tablet, can be simulated by managing the jog rate decay and sending Grbl the associated jog commands. While this jogging implementation requires more initial work by a GUI, it is also inherently more flexible because you have complete deterministic control of how jogging behaves.