Hello Guest it is March 29, 2024, 08:17:05 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - joeaverage

Pages: « 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 »
2571
Mach4 General Discussion / Re: Jerky motion
« on: April 22, 2019, 12:09:33 AM »
Hi,

Quote
The polling frequency should  be set at 100Hz or higher

Firstly the 'Polling Frequency' is a new one to me. I know the Ethernet SmoothSteper has a 'Refresh Rate' set at
40Hz (default). That is the rate at which the controller and Mach swap data packets.

Each outgoing Mach data packet will contain as many as 50 PVT (Position Velocity Time) data lines. Each time slice is
1 millisecond wide. These time slices get stacked up in the controller buffer. Any given time slice will contain position
data for ALL axes of the machine and ALL axes will move simultaneously. There should be none of this 'one axis moves
a bit and then the next axis moves a bit'

Quite frankly I think the Refresh Rate (I'm assuming its synonymous Polling Frequency) is a red herring. It has no bearing
on the granularity of the PVT time slices.

The Ethernet SmoothStepper has a buffer of 180 ms (default) of motion. I've never seen it drop below 150ms. If the buffer
runs out Mach crashes. May I suggest you find the comparable spec data for your controller and monitor the buffer. The ESS
plugin has a live diagnostic to monitor the buffer and would guess your controller has a similar feature.

Craig


2572
Hi Russ,

Quote
No real harm if that is the only board being hit ?
If closed, they might show up in a more popular place ?
They're relentless !

Your right, that board has seen that little traffic that it doesn't really matter, and yes there is a possibility that if the board
were removed they might find another more annoying lace to post.

They really piss me off.....I would still like to see all new members first post be moderated, at least it would give
moderators/administrators an IP address.

Craig

2573
Hi,
presume the rash of spam on the Downloads/Others board are some organized setup where a machine establishes a new
account and then posts spam mail. If the other posts, about 15 of them by my count, were moved could the 'Others' board be
closed and thwart the spammer?

Craig

2574
Mach4 General Discussion / Re: Step pulse duty cycle
« on: April 21, 2019, 04:56:24 AM »
Hi,

Quote
My drive is not labelled as Leadshine, though it looks the same.

Man.... a Leadshine copy???....the Chinese getting ripped off by whom....some other Chinese outfit??

So what brand is it?

Quote
The set up time for the step signals is 2.5us and the current requirement is 10ma, so the ESS should be ok if I read and understand that right.

I think that the current limit resisitor is such that with the low input voltage (5V) that the current is insufficient to reliably
and quickly signal the drive.

Craig


2575
Mach4 General Discussion / Re: Step pulse duty cycle
« on: April 20, 2019, 06:00:52 PM »
Hi,
that's made by Leadshine. Manual attached.

Craig

2576
Mach4 General Discussion / Re: Step pulse duty cycle
« on: April 20, 2019, 04:42:49 PM »
Hi,

Quote
Im only using the opto's on the inputs for the 36v switches.

OK, that makes sense. I suppose then that you do not have any buffering between the ESS and your drivers?

According to the specs the ESS should source or sin 24mA, surely that would be enough to drive the input optocouplers
of your stepper drivers. Do you have a circuit diagram of the input circuits of the drivers? I'm wondering if they are 24V
tolerant, in which case they are likely to have a series current limit resistor but may then reduce the current to borderline
or below when driven with the 5V outputs of the ESS.

Craig


2577
Mach4 General Discussion / Re: Step pulse duty cycle
« on: April 20, 2019, 04:16:21 PM »
Hi,
I think you are right. Opto-isolators can be as slow as a wet week depending on the model and how you set them up.

I have attached a pic of two very common optocouplers. Note that the phototransistor in one has no external base connection.
Thus the sole way it can turn on is light from the photodiode, thus the photodiode needs to brightly illuminate the phototranistor,
commonly 10mA or more. Typically the time response is slow, 10-20us with these devices and you would struggle to
pass a 100kHz signal through it.

The other optocoupler pictured has an external connection to the base. That is typically biased to about 0.6V such that the
phototransistor is on the threshold of conduction. Thus the light from the photodiode need be very much less intense
to cause the phototransistor to conduct, less than 1mA photodiode current. Response time is likewise much
improved, of the order of 1us.

The extra biasing circuitry, especially being so heat sensitive, means that the biased photocouplers are used only as needed
in comparison to the simpler non-biased optocoupler.

The question is why are you so hung up on optoisolators? Firstly its common for the input of stepper driver to have optocouplers
built in already. There is no need to isolate at the ESS/BoB end and THEN AGAIN at the driver end.

I use:

https://www.homanndesigns.com/index.php?main_page=product_info&cPath=54_22&products_id=59&zenid=n2f38qp4ho6mv9eb9rm7hhp7a0

from Homann Designs in Australia, I live in New Zealnd so they are kind of local to me. These are very simple and plain
bi-directional BoBs WITHOUT optoisolators. I've been using them for over five years and have not blown anything
up yet, and I can blow stuff up real easy!

If fact I did a poll a while back:

https://www.machsupport.com/forum/index.php?topic=39723.0

Only five people replied, a bit disappointing, but none of those five people (100%) have blown up a PC because they did
not use opto-isolators. I'm not saying you can't blow up a PC but it doesn't happen much either.

The advantage of the Homann BoBs is that without the opto's they are as fast as the TTL buffers used, ie tens of MHz.

The C10 is cheap enough, $23USD and bi-directional. Note it has no bloody opto's . Neither does it have any relays
for the spindle nor a PWM to analog circuit for a VFD, you would have to make and add those as required.

https://cnc4pc.com/c10-bi-directional-parallel-port-interface-card.html

Craig


2578
Hi,
there are a couple of ways that an Estop event can be handled.

The traditional manner and still is the norm in industrial machines is that an Estop (or limit switch event) depowers
the entire machine by causing the main supply contactor to drop out.

Another way more common on hobbyists machines is that when an Estop occurs then Mach will turn the spindle off.

The objection to this later method is that it relies on Mach (a computer program) to do its thing, should the program
prove to be buggy the machine might not shut down. In many countries that would (legally) be considered unsafe.

I participated quite heavily in:
https://www.machsupport.com/forum/index.php?topic=34023
Zuxtah had relay to depower the VFD in the manner common in industrial practice. He could also have chosen to add
a line or two of code to cause Mach to command the VFD off in response to an Estop.

Speed override is a Mach function. Thus if you override the speed then Mach will increase the commanded frequency
of the VFD and the spindle would speed up. The code to do that was discussed quite extensively.

Quote
If Mach4 supports modbus, I think it should be documented and the software setup to handle typical spindle functions as a minimum. Browsing the forum and piecing together various experiments (great stuff there and thanks for that) to get something working seems like a poor way to support a significant capability.

One of the perennial complaints about Mach4, and to a certain extent Mach3 which preceded it, is that the documentation
is not up to it. The reality is that NFS is a very small company and does not have the resources to employ technical document
writers. Any documentation has to be written by the person who has just developed the 'new' feature and simply put their time
and energy is best devoted to development.....rather than prosaic documentation.

This is why the forum is so important to Mach....we the users sort of document it as we go.

Craig

2579
Mach4 General Discussion / Re: Step pulse duty cycle
« on: April 20, 2019, 05:33:42 AM »
Hi,
you say you are using an ESS but what BoB are you using?. I'm beginning to wonder if the buffer/output circuit of
your BoB is not fast enough. Do you have a scope or access to one? I think to resolve whether the ESS or the BoB
or the driver is responsible is going to require a scope to diagnose.

The second issue is the inductance of the steppers. Certainly at no or low loads you would expect a stepper to spin quickly
but at higher loads the same stepper will stall or lose steps. Without a close comparison of the rotational load it
not really possible to compare one installation to another.

Do you have a torque and inductance spec for your steppers? What brand/make/model are they?

Craig

2580
General Mach Discussion / Re: Slaving closed loop stepper motors
« on: April 20, 2019, 02:03:57 AM »
Hi,
I don't now a huge amount about AC servos.

I wanted a high torque (5-6Nm) spindle at round 3000-5000 rpm for milling steel. My 24000 rpm spindle is very nice but
has low torque and very low power at low rpm, an impossible combination for milling steel.

I ended up buying an Allen Bradley 1.8kW 3500 rpm AC servo and matching servo drive second hand.

Talk about 'open my eyes' to the reality of modern AC servos. Its about 10 years old so its far from state of the art anyway
but the speed, accuracy and power just humble any stepper. That does not account for the multitude of control strategies
modern servos offer, torque, velocity and positions modes or a mix, indexing, in-drive oscilloscope tuning.....the list goes on.

Had I realized just how capable AC servos are I would have hung out and got them rather than steppers. Don't get me
wrong, steppers are good, but good doesn't compare to f*********king fantastic!

Craig

Pages: « 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 »