Changes for page LSS Communication Protocol
Last modified by Eric Nantel on 2025/06/06 07:47
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... ... @@ -1,3 +1,5 @@ 1 +{{toc depth="3"/}} 2 + 1 1 = Protocol concepts = 2 2 3 3 The Lynxmotion Smart Servo (LSS) protocol was created in order to be as simple and straightforward as possible from a user perspective, while at the same time trying to stay compact and robust yet highly versatile. Almost everything one might expect to be able to configure for a smart servo motor is available. ... ... @@ -179,37 +179,37 @@ 179 179 180 180 == Details == 181 181 182 -==== __1. Limp (**L**)__ ==== 184 +====== __1. Limp (**L**)__ ====== 183 183 184 184 Example: #5L<cr> 185 185 186 186 This action causes the servo to go "limp". The microcontroller will still be powered, but the motor will not. As an emergency safety feature, should the robot not be doing what it is supposed to or risks damage, use the broadcast ID to set all servos limp #254L<cr>. 187 187 188 -__2. Halt & Hold (**H**)__ 190 +====== __2. Halt & Hold (**H**)__ ====== 189 189 190 190 Example: #5H<cr> 191 191 192 192 This action overrides whatever the servo might be doing at the time the command is received (accelerating, moving continuously etc.) and causes it to stop immediately and hold that position. 193 193 194 -__3. Timed move (**T**)__ 196 +====== __3. Timed move (**T**)__ ====== 195 195 196 196 Example: #5P1500T2500<cr> 197 197 198 198 Timed move can be used only as a modifier for a position (P) action. The units are in milliseconds, so a timed move of 2500 milliseconds would cause the servo to rotate from its current position to the desired position in 2.5 seconds. This command is in place to ensure backwards compatibility with the SSC-32 / 32U protocol. 199 199 200 -__4. Speed (**S**)__ 202 +====== __4. Speed (**S**)__ ====== 201 201 202 202 Example: #5P1500S750<cr> 203 203 204 204 This command is a modifier only for a position (P) action and determines the speed of the move in microseconds per second. A speed of 750 microseconds would cause the servo to rotate from its current position to the desired position at a speed of 750 microseconds per second. This command is in place to ensure backwards compatibility with the SSC-32 / 32U protocol. 205 205 206 -__5. (Relative) Move in Degrees (**MD**)__ 208 +====== __5. (Relative) Move in Degrees (**MD**)__ ====== 207 207 208 208 Example: #5MD123<cr> 209 209 210 210 The relative move command causes the servo to read its current position and move the specified number of tenths of degrees in the corresponding position. For example if the servo is set to rotate CW (default) and an MD command of 123 is sent to the servo, it will cause the servo to rotate clockwise by 12.3 degrees. Negative commands would cause the servo to rotate in the opposite configured direction. 211 211 212 -__6. Origin Offset Action (**O**)__ 214 +====== __6. Origin Offset Action (**O**)__ ====== 213 213 214 214 Example: #5O2400<cr> 215 215 ... ... @@ -233,7 +233,7 @@ 233 233 234 234 This command allows you to change the origin of the servo in relation to the factory zero position in EEPROM. The setting will be saved upon servo reset / power cycle. Origin offset configuration commands are not cumulative and always relate to factory zero. The new origin is also used in RC mode. 235 235 236 -__7. Angular Range (**AR**)__ 238 +====== __7. Angular Range (**AR**)__ ====== 237 237 238 238 Example: #5AR1800<cr> 239 239 ... ... @@ -257,7 +257,7 @@ 257 257 258 258 This command allows you to change the total angular range of the servo in tenths of degrees in EEPROM. The setting will be saved upon servo reset / power cycle. 259 259 260 -__8. Position in Pulse (**P**)__ 262 +====== __8. Position in Pulse (**P**)__ ====== 261 261 262 262 Example: #5P2334<cr> 263 263 ... ... @@ -270,7 +270,7 @@ 270 270 This command queries the current angular position in PWM "units". The user must take into consideration that the response includes any angular range and origin configurations in order to determine the actual angle. 271 271 Valid values for QP are {-500, [500, 2500], -2500}. Values outside the [500, 2500] range are given a negative corresponding end point value to indicate they are out of bounds (note that if the servo is physically located at one of the endpoints, it may return a negative number if it is a fraction of a degree beyond the position). 272 272 273 -__9. Position in Degrees (**D**)__ 275 +====== __9. Position in Degrees (**D**)__ ====== 274 274 275 275 Example: #5PD1456<cr> 276 276 ... ... @@ -284,7 +284,7 @@ 284 284 285 285 This means the servo is located at 13.2 degrees. 286 286 287 -__10. Wheel Mode in Degrees (**WD**)__ 289 +====== __10. Wheel Mode in Degrees (**WD**)__ ====== 288 288 289 289 Ex: #5WD900<cr> 290 290 ... ... @@ -296,7 +296,7 @@ 296 296 297 297 The servo replies with the angular speed in tenths of degrees per second. A negative sign would indicate the opposite direction (for factory default a negative value would be counter clockwise). 298 298 299 -__11. Wheel Mode in RPM (**WR**)__ 301 +====== __11. Wheel Mode in RPM (**WR**)__ ====== 300 300 301 301 Ex: #5WR40<cr> 302 302 ... ... @@ -308,7 +308,7 @@ 308 308 309 309 The servo replies with the angular speed in rpm. A negative sign would indicate the opposite direction (for factory default a negative value would be counter clockwise). 310 310 311 -__12. Speed in Degrees (**SD**)__ 313 +====== __12. Speed in Degrees (**SD**)__ ====== 312 312 313 313 Ex: #5SD1800<cr> 314 314 ... ... @@ -333,7 +333,7 @@ 333 333 334 334 Using the CSD command sets the servo's maximum speed which is saved in EEPROM. In the example above, the servo's maximum speed will be set to 180.0 degrees per second. When the servo is powered on (or after a reset), the CSD value is used. Note that CSD and CSR (described below) are effectively the same, but allow the user to specify the speed in either unit. The last command (either CSR or CSD) is what the servo uses for that session. 335 335 336 -__13. Speed in RPM (**SR**)__ 338 +====== __13. Speed in RPM (**SR**)__ ====== 337 337 338 338 Ex: #5SD45<cr> 339 339 ... ... @@ -358,7 +358,7 @@ 358 358 359 359 Using the CSR command sets the servo's maximum speed which is saved in EEPROM. In the example above, the servo's maximum speed will be set to 45rpm. When the servo is powered on (or after a reset), the CSR value is used. Note that CSD and CSR are effectively the same, but allow the user to specify the speed in either unit. The last command (either CSR or CSD) is what the servo uses for that session. 360 360 361 -__14. Angular Stiffness (**AS**)__ 363 +====== __14. Angular Stiffness (**AS**)__ ====== 362 362 363 363 The servo's rigidity / angular stiffness can be thought of as (though not identical to) a damped spring in which the value affects the stiffness and embodies how much, and how quickly the servo tried keep the requested position against changes. 364 364 ... ... @@ -386,7 +386,7 @@ 386 386 387 387 Writes the desired angular stiffness value to memory. 388 388 389 -__15. Angular Hold Stiffness (**AH**)__ 391 +====== __15. Angular Hold Stiffness (**AH**)__ ====== 390 390 391 391 The angular holding stiffness determines the servo's ability to hold a desired position under load. Values can be from -10 to 10, with the default being 0. Note that negative values mean the final position can be easily deflected. 392 392 ... ... @@ -406,19 +406,19 @@ 406 406 407 407 This writes the angular holding stiffness of servo #5 to 2 to EEPROM 408 408 409 -__15b: Angular Acceleration (**AA**)__ 411 +====== __15b: Angular Acceleration (**AA**)__ ====== 410 410 411 411 {More details to come} 412 412 413 -__15c: Angular Deceleration (**AD**)__ 415 +====== __15c: Angular Deceleration (**AD**)__ ====== 414 414 415 415 {More details to come} 416 416 417 -__15d: Motion Control (**MC**)__ 419 +====== __15d: Motion Control (**MC**)__ ====== 418 418 419 419 {More details to come} 420 420 421 -__16. RGB LED (**LED**)__ 423 +====== __16. RGB LED (**LED**)__ ====== 422 422 423 423 Ex: #5LED3<cr> 424 424 ... ... @@ -436,7 +436,7 @@ 436 436 437 437 Configuring the LED color via the CLED command sets the startup color of the servo after a reset or power cycle. Note that it also changes the session's LED color immediately as well. 438 438 439 -__17. Identification Number__ 441 +====== __17. Identification Number__ ====== 440 440 441 441 A servo's identification number cannot be set "on the fly" and must be configured via the CID command described below. The factory default ID number for all servos is 0. Since smart servos are intended to be daisy chained, in order to respond differently from one another, the user must set different identification numbers. Servos with the same ID and baud rate will all receive and react to the same commands. 442 442 ... ... @@ -452,7 +452,7 @@ 452 452 453 453 Setting a servo's ID in EEPROM is done via the CID command. All servos connected to the same serial bus will be assigned that ID. In most situations each servo must be set a unique ID, which means each servo must be connected individually to the serial bus and receive a unique CID number. It is best to do this before the servos are added to an assembly. Numbered stickers are provided to distinguish each servo after their ID is set, though you are free to use whatever alternative method you like. 454 454 455 -__18. Baud Rate__ 457 +====== __18. Baud Rate__ ====== 456 456 457 457 A servo's baud rate cannot be set "on the fly" and must be configured via the CB command described below. The factory default baud rate for all servos is 9600. Since smart servos are intended to be daisy chained, in order to respond to the same serial bus, all servos in that project should ideally be set to the same baud rate. Setting different baud rates will have the servos respond differently and may create issues. Available baud rates are: 9.6 kbps, 19.2 kbps, 38.4 kbps, 57.6 kbps, 115.2 kbps, 230.4 kbps, 250.0 kbps, 460.8 kbps, 500.0 kbps, 750.0 kbps*, 921.6 kbps*. Servos are shipped with a baud rate set to 9600. The baud rates are currently restricted to those above. 458 458 \*: Current tests reveal baud rates above 500 kbps are unstable and can cause timeouts. Please keep this in mind if using those / testing them out. ... ... @@ -469,7 +469,7 @@ 469 469 470 470 Sending this command will change the baud rate associated with servo ID 5 to 9600 bits per second. 471 471 472 -__19. Gyre Rotation Direction__ 474 +====== __19. Gyre Rotation Direction__ ====== 473 473 474 474 "Gyre" is defined as a circular course or motion. The effect of changing the gyre direction is as if you were to use a mirror image of a circle. CW = 1; CCW = -1. The factory default is clockwise (CW). 475 475 ... ... @@ -487,7 +487,7 @@ 487 487 488 488 This changes the gyre direction as described above and also writes to EEPROM. 489 489 490 -__20. First / Initial Position (pulse)__ 492 +====== __20. First / Initial Position (pulse)__ ====== 491 491 492 492 In certain cases, a user might want to have the servo move to a specific angle upon power up. We refer to this as "first position". The factory default has no first position value stored in EEPROM and therefore upon power up, the servo remains limp until a position (or hold command) is assigned. FP and FD are different in that FP is used for RC mode only, whereas FD is used for smart mode only. 493 493 ... ... @@ -503,7 +503,7 @@ 503 503 504 504 This configuration command means the servo, when set to RC mode, will immediately move to an angle equivalent to having received an RC pulse of 1550 microseconds upon power up. Sending a CFP command without a number results in the servo remaining limp upon power up (i.e. disabled). 505 505 506 -__21. First / Initial Position (Degrees)__ 508 +====== __21. First / Initial Position (Degrees)__ ====== 507 507 508 508 In certain cases, a user might want to have the servo move to a specific angle upon power up. We refer to this as "first position". The factory default has no first position value stored in EEPROM and therefore upon power up, the servo remains limp until a position (or hold command) is assigned. FP and FD are different in that FP is used for RC mode only, whereas FD is used for smart mode only. 509 509 ... ... @@ -519,37 +519,37 @@ 519 519 520 520 This configuration command means the servo, when set to smart mode, will immediately move to 6.4 degrees upon power up. Sending a CFD command without a number results in the servo remaining limp upon power up. 521 521 522 -__22. Query Target Position in Degrees (**QDT**)__ 524 +====== __22. Query Target Position in Degrees (**QDT**)__ ====== 523 523 524 524 Ex: #5QDT<cr> might return *5QDT6783<cr> 525 525 526 526 The query target position command returns the target angle during and after an action which results in a rotation of the servo horn. In the example above, the servo is rotating to a virtual position of 678.3 degrees. Should the servo not have a target position or be in wheel mode, it will respond without a number (Ex: *5QDT<cr>). 527 527 528 -__23. Query Model String (**QMS**)__ 530 +====== __23. Query Model String (**QMS**)__ ====== 529 529 530 530 Ex: #5QMS<cr> might return *5QMSLSS-HS1cr> 531 531 532 532 This reply means the servo model is LSS-HS1, meaning a high speed servo, first revision. 533 533 534 -__23b. Query Model (**QM**)__ 536 +====== __23b. Query Model (**QM**)__ ====== 535 535 536 536 Ex: #5QM<cr> might return *5QM68702699520cr> 537 537 538 538 This reply means the servo model is 0xFFF000000 or 100, meaning a high speed servo, first revision. 539 539 540 -__24. Query Serial Number (**QN**)__ 542 +====== __24. Query Serial Number (**QN**)__ ====== 541 541 542 542 Ex: #5QN<cr> might return *5QN~_~_<cr> 543 543 544 544 The number in the response is the servo's serial number which is set and cannot be changed. 545 545 546 -__25. Query Firmware (**QF**)__ 548 +====== __25. Query Firmware (**QF**)__ ====== 547 547 548 548 Ex: #5QF<cr> might return *5QF11<cr> 549 549 550 550 The integer in the reply represents the firmware version with one decimal, in this example being 1.1 551 551 552 -__26. Query Status (**Q**)__ 554 +====== __26. Query Status (**Q**)__ ====== 553 553 554 554 Ex: #5Q<cr> might return *5Q6<cr>, which indicates the motor is holding a position. 555 555 ... ... @@ -566,25 +566,25 @@ 566 566 |ex: *5Q9<cr>|Stuck|Motor cannot perform request movement at current speed setting 567 567 |ex: *5Q10<cr>|Blocked|Similar to stuck, but the motor is at maxiumum duty and still cannot move (i.e.: stalled) 568 568 569 -__27. Query Voltage (**QV**)__ 571 +====== __27. Query Voltage (**QV**)__ ====== 570 570 571 571 Ex: #5QV<cr> might return *5QV11200<cr> 572 572 573 573 The number returned has one decimal, so in the case above, servo with ID 5 has an input voltage of 11.2V (perhaps a three cell LiPo battery). 574 574 575 -__28. Query Temperature (**QT**)__ 577 +====== __28. Query Temperature (**QT**)__ ====== 576 576 577 577 Ex: #5QT<cr> might return *5QT564<cr> 578 578 579 579 The units are in tenths of degrees Celcius, so in the example above, the servo's internal temperature is 56.4 degrees C. To convert from degrees Celcius to degrees Farenheit, multiply by 1.8 and add 32. Therefore 56.4C = 133.52F. 580 580 581 -__29. Query Current (**QC**)__ 583 +====== __29. Query Current (**QC**)__ ====== 582 582 583 583 Ex: #5QC<cr> might return *5QC140<cr> 584 584 585 585 The units are in milliamps, so in the example above, the servo is consuming 140mA, or 0.14A. 586 586 587 -__30. RC Mode (**CRC**)__ 589 +====== __30. RC Mode (**CRC**)__ ====== 588 588 589 589 This command puts the servo into RC mode (position or continuous), where it will only respond to RC pulses. Note that because this is the case, the servo will no longer accept serial commands. The servo can be placed back into smart mode by using the button menu. 590 590 ... ... @@ -596,13 +596,13 @@ 596 596 597 597 EX: #5CRC<cr> 598 598 599 -__31. RESET__ 601 +====== __31. RESET__ ====== 600 600 601 601 Ex: #5RESET<cr> or #5RS<cr> 602 602 603 603 This command does a "soft reset" (no power cycle required) and reverts all commands to those stored in EEPROM (i.e. configuration commands). 604 604 605 -__32. DEFAULT & CONFIRM__ 607 +====== __32. DEFAULT & CONFIRM__ ====== 606 606 607 607 Ex: #5DEFAULT<cr> 608 608 ... ... @@ -614,7 +614,7 @@ 614 614 615 615 Note that after the CONFIRM command is sent, the servo will automatically perform a RESET. 616 616 617 -__33. UPDATE & CONFIRM__ 619 +====== __33. UPDATE & CONFIRM__ ====== 618 618 619 619 Ex: #5UPDATE<cr> 620 620