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Metal Cutting Table —> run-a-way machine while doing homing routine

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    Metal Cutting Table —> run-a-way machine while doing homing routine

    I have never seen this machine do this and I have been at this job for over seven years with company

    The operator turned on the machine and gave the command for the machine to go where the machine does the homing routine well while going to where it needs be to do this routine the computer reboot and the machine crashed into the end stops and sheared off two bolts on the drive gear mounting assembly

    I want to what the hell happen to this machine for it to do this
    after fixing the broken bolts the machine works fine now
    9 PC LCD Monitor
    6 LCD Flat Screen TV
    30 Desk Top Switching Power Supply
    10 Battery Charger Switching Power Supply for Power Tool
    6 18v Lithium Battery Power Boards for Tool Battery Packs
    1 XBox 360 Switching Power Supply and M Board
    25 Servo Drives 220/460 3 Phase
    6 De-soldering Station Switching Power Supply 1 Power Supply
    1 Dell Mother Board
    15 Computer Power Supply
    1 HP Printer Supply & Control Board * lighting finished it *


    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
    2 Hem Saw Computer Stack Board

    All of these had CAPs POOF
    All of the mosfet that are taken out by bad caps

    #2
    Re: Metal Cutting Table —> run-a-way machine while doing homing routine

    poor design, it should have had mechanical limit switches incase of computer failure.

    as for the crash, hey - it's old.
    could be bad caps, dried paste on a heatsink, a dead fan - loads of things.
    even failing ram or harddrive.

    Comment


      #3
      Re: Metal Cutting Table —> run-a-way machine while doing homing routine

      The machine's I/O board must be dumb. If the PC tells it to move and then dies, the motor keeps going? The I/O board should always look at limit switches.

      In these kind of systems, I add a hardware watchdog. If the PC is not sending a heartbeat pulse, a watchdog IC or even 555 can disable the machine by asserting emergency stop. It takes about 1-2 seconds though, unless the PC is quick.

      If you have welding or heavy equipment nearby, AC power is dirty and EMI can also cause trouble.
      A PC in a shop environment is difficult because air is dirty too. If you have people cutting and grinding steel, the PC's fan/PSU will quickly plug up and overheat.
      I put the PC/monitor in a cabinet with a plexiglass door and rear 4" fan blowing in air. Used a pie plate and big Chevy 427 air filter on the fan intake, so no shop dust got into the PC. Positive air pressure in the cabinet blew out dust and keeps things cool.

      Comment


        #4
        Re: Metal Cutting Table —> run-a-way machine while doing homing routine

        Originally posted by redwire View Post
        In these kind of systems, I add a hardware watchdog. If the PC is not sending a heartbeat pulse, a watchdog IC or even 555 can disable the machine by asserting emergency stop. It takes about 1-2 seconds though, unless the PC is quick
        Can you please explain how you add this to the system
        Where do you get the heartbeat signal from

        I call tech support and was told that the Servo Drive Controller are send the run and stop commands from the computer controller and are not update until the end CAD program or until it hit the limits switch which are part of the computer controller not part of safety relay circuit

        To me this is not a good setup

        Will what you are taking about will this work on this machine setup
        Last edited by sam_sam_sam; 12-04-2018, 02:53 PM.
        9 PC LCD Monitor
        6 LCD Flat Screen TV
        30 Desk Top Switching Power Supply
        10 Battery Charger Switching Power Supply for Power Tool
        6 18v Lithium Battery Power Boards for Tool Battery Packs
        1 XBox 360 Switching Power Supply and M Board
        25 Servo Drives 220/460 3 Phase
        6 De-soldering Station Switching Power Supply 1 Power Supply
        1 Dell Mother Board
        15 Computer Power Supply
        1 HP Printer Supply & Control Board * lighting finished it *


        These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

        1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
        2 Hem Saw Computer Stack Board

        All of these had CAPs POOF
        All of the mosfet that are taken out by bad caps

        Comment


          #5
          Re: Metal Cutting Table —> run-a-way machine while doing homing routine

          Originally posted by sam_sam_sam View Post
          Can you please explain how you add this to the system
          Where do you get the heartbeat signal from
          Adding watchdog hardware to a system is relatively easy. The problem typically boils down to one of software that wasn't designed with the idea of "talking" to it.

          You can't have some periodic aspect of the software "stroking" the watchdog -- because those things tend to run even when the software has otherwise crashed.

          If you let the "idle loop" stroke the watchdog, then you're relying on the system having "idle time" often enough to prevent the watchdog from timing out.

          If stroking the watchdog is a trivial act, then its relatively easy for a rogue piece of code to effectively stroke it -- even though the system itself is hosed.

          If stroking the watchdog is an UNPRIVILEGED act, then some non-system actor can end up stroking it.

          [Remember, the system is no longer behaving properly. So, you can't know with any certainty how ANYTHING is behaving at this point in time]

          I call tech support and was told that the Servo Drive Controller are send the run and stop commands from the computer controller and are not update until the end CAD program or until it hit the limits switch which are part of the computer controller not part of safety relay circuit
          Yes. A typical "slap together some COTS modules and hope everything works as planned. As the modules don't share intimate details of their operating state, there is no way for one to interact with another WHILE that "other" is performing its task.

          E.g., unplug the cable connecting them and the "STOP" command will never arrive ("You're not supposed to do that!").

          To me this is not a good setup

          Will what you are taking about will this work on this machine setup
          Ideally, limit switches cause all motion to cease when the design conditions have been exceeded. Open a "guard" and now a human may be exposed to lethal voltages, mechanisms, etc. -- don't rely on any software "smarts" to cause the mechanisms to stop, force them to stop by removing power or explicitly driving an "inhibit" signal.

          But, there's a limit (no pun intended) as to how much you can do with "simple" rules. Are you sure a maintenance tech can't wire the limit switches "backwards"/reversed? Chances are, the machine NEVER expects to encounter them in normal operation -- relying on something else to provide positional feedback. So, you may never "know" that the switches aren't properly wired unless you EXPLICTLY test them (deliberately drive the mechanism into the stops).

          If, in the interest of manufacturing economy, the wire harnesses for the two limit switches (in a particular pair) are identically plugged, what's to guarantee that the "left" switch isn't plugged in where the "right" switch should be? If the left switch inhibits LEFTWARD motion (and not ALL motion), then the mechanism can be "moving right" when it crashes into the RIGHT limit switch. But, as that switch is presently connected where the LEFT switch should have been (effectively making it the left switch in the eyes of the system) AND as the LEFT switch only interrupts leftward motion, the mechanism gleefully continues into the stop, unaware of the switch's actuation.

          In a safe/validated system, any time you detect something that isn't as it should be, the only practical recourse is to stop and ask for a "smarter being" to resolve the problem (cuz you don't know what inputs/controls YOU can trust)

          Comment


            #6
            Re: Metal Cutting Table —> run-a-way machine while doing homing routine

            Originally posted by Curious.George View Post
            Adding watchdog hardware to a system is relatively easy. The problem typically boils down to one of software that wasn't designed with the idea of "talking" to it.

            You can't have some periodic aspect of the software "stroking" the watchdog -- because those things tend to run even when the software has otherwise crashed.

            If you let the "idle loop" stroke the watchdog, then you're relying on the system having "idle time" often enough to prevent the watchdog from timing out.

            If stroking the watchdog is a trivial act, then its relatively easy for a rogue piece of code to effectively stroke it -- even though the system itself is hosed.

            If stroking the watchdog is an UNPRIVILEGED act, then some non-system actor can end up stroking it.

            [Remember, the system is no longer behaving properly. So, you can't know with any certainty how ANYTHING is behaving at this point in time]



            Yes. A typical "slap together some COTS modules and hope everything works as planned. As the modules don't share intimate details of their operating state, there is no way for one to interact with another WHILE that "other" is performing its task.

            E.g., unplug the cable connecting them and the "STOP" command will never arrive ("You're not supposed to do that!").



            Ideally, limit switches cause all motion to cease when the design conditions have been exceeded. Open a "guard" and now a human may be exposed to lethal voltages, mechanisms, etc. -- don't rely on any software "smarts" to cause the mechanisms to stop, force them to stop by removing power or explicitly driving an "inhibit" signal.

            But, there's a limit (no pun intended) as to how much you can do with "simple" rules. Are you sure a maintenance tech can't wire the limit switches "backwards"/reversed? Chances are, the machine NEVER expects to encounter them in normal operation -- relying on something else to provide positional feedback. So, you may never "know" that the switches aren't properly wired unless you EXPLICTLY test them (deliberately drive the mechanism into the stops).

            If, in the interest of manufacturing economy, the wire harnesses for the two limit switches (in a particular pair) are identically plugged, what's to guarantee that the "left" switch isn't plugged in where the "right" switch should be? If the left switch inhibits LEFTWARD motion (and not ALL motion), then the mechanism can be "moving right" when it crashes into the RIGHT limit switch. But, as that switch is presently connected where the LEFT switch should have been (effectively making it the left switch in the eyes of the system) AND as the LEFT switch only interrupts leftward motion, the mechanism gleefully continues into the stop, unaware of the switch's actuation.

            In a safe/validated system, any time you detect something that isn't as it should be, the only practical recourse is to stop and ask for a "smarter being" to resolve the problem (cuz you don't know what inputs/controls YOU can trust)
            One note about month ago something very similar had happened but this time it was running a CAD program ( all it was doing was a straight cut a cross the plate) it was running and computer controller rebooted and when it finished rebooting the machine stopped running

            ( it was not finished cutting the plate )

            ( I was not told about this until today)

            I understand what you have here ( and I agree with most of what you have point out above ) but I am going to ask the question anyway

            What would be the best thing to do in this situation so that no one gets hurt or the machine destroyed it self because the computer controller goes and does a reboot and does not send a STOP command until the computer controller finishes it reboot

            The tech support person main concern is why the computer controller is doing the rebooting in the first place

            Which I agree with that but I do not think that this is only problem or the hole answer to this problem

            Or

            I could be wrong
            Last edited by sam_sam_sam; 12-04-2018, 07:19 PM.
            9 PC LCD Monitor
            6 LCD Flat Screen TV
            30 Desk Top Switching Power Supply
            10 Battery Charger Switching Power Supply for Power Tool
            6 18v Lithium Battery Power Boards for Tool Battery Packs
            1 XBox 360 Switching Power Supply and M Board
            25 Servo Drives 220/460 3 Phase
            6 De-soldering Station Switching Power Supply 1 Power Supply
            1 Dell Mother Board
            15 Computer Power Supply
            1 HP Printer Supply & Control Board * lighting finished it *


            These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

            1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
            2 Hem Saw Computer Stack Board

            All of these had CAPs POOF
            All of the mosfet that are taken out by bad caps

            Comment


              #7
              Re: Metal Cutting Table —> run-a-way machine while doing homing routine

              should have a limit switch that cuts all power to the machine . i was fitting these for the electricians in factories in the early 1980.s . same sort of switches for guards being opened . all power off and not able to reset without all switches closed .. almost forgot the big red emergency stop buttons fitted in handy places .
              i thought this stuff would be still standard practice but maybe with canbus system to detect which switch is open for easy diagnosis for the technicians .

              Comment


                #8
                Re: Metal Cutting Table —> run-a-way machine while doing homing routine

                Originally posted by petehall347 View Post
                should have a limit switch that cuts all power to the machine . i was fitting these for the electricians in factories in the early 1980.s . same sort of switches for guards being opened . all power off and not able to reset without all switches closed .. almost forgot the big red emergency stop buttons fitted in handy places .
                i thought this stuff would be still standard practice but maybe with canbus system to detect which switch is open for easy diagnosis for the technicians .
                Yes it has two limit switch’s but they only tell the controller whether or not the machine is square and this only use when homing the machine when first turn the machine ON ——>

                The only other time it uses these limit switch is when you run the machine to each end of the bed

                That is all it is used for from what I have seen these switch’s are used for also the limit switch are active about a foot before it gets to the end stops

                So to do anything before these limit switch is going to not work because of the way this machine is setup
                Last edited by sam_sam_sam; 12-04-2018, 07:43 PM.
                9 PC LCD Monitor
                6 LCD Flat Screen TV
                30 Desk Top Switching Power Supply
                10 Battery Charger Switching Power Supply for Power Tool
                6 18v Lithium Battery Power Boards for Tool Battery Packs
                1 XBox 360 Switching Power Supply and M Board
                25 Servo Drives 220/460 3 Phase
                6 De-soldering Station Switching Power Supply 1 Power Supply
                1 Dell Mother Board
                15 Computer Power Supply
                1 HP Printer Supply & Control Board * lighting finished it *


                These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                2 Hem Saw Computer Stack Board

                All of these had CAPs POOF
                All of the mosfet that are taken out by bad caps

                Comment


                  #9
                  Re: Metal Cutting Table —> run-a-way machine while doing homing routine

                  Originally posted by sam_sam_sam View Post
                  What would be the best thing to do in this situation so that no one gets hurt or the machine destroyed it self because the computer controller goes and does a reboot and does not send a STOP command until the computer controller finishes it reboot
                  The "least offensive" approach would be to see if the device that does the cutting (the thing that GETS the START/STOP commands) can be configured to "stop unless told to continue". Then, have the controller (the thing that SENDS the START/STOP commands) reissue the START, periodically, as a "CONTINUE".

                  That, undoubtedly, would require changes that you can't make to the system (I assume it is a third-party design?).

                  You can't guarantee that the machine, the work-in-progress AND the user all remain "safe" (salvageable) as there are myriad ways things can go south and you have to come up with a SIMPLE (i.e., robust/reliable) backstop to cover all cases.

                  So, you prioritize them:
                  • in most cases, operator/user safety is paramount. People can bring lawsuits (and drag OSHA and insurers into the mess) so you want to avoid pissing them off.
                  • the machine is usually the second most precious item (though not always). So, once you've assured yourself that your solution protects the user/operator, you then try to address the machine's integrity.
                  • the workpiece (and any other "process-related" stuff) tends to be the most expendable -- though that doesn't say you would WANT to destroy or damage it if you can avoid doing so.

                  Pulling power to the machine TENDS to be the easiest way to protect the user. This assumes that the machine will "wind down" whatever it is doing in a reasonably prompt manner. That may not be the case as you can have considerable energy stored in "mechanisms".

                  On some machines, you may be able to interrupt the power to individual actuators without bringing the whole machine "down". Of course, that also assumes the rest of the mcahine was designed with that possibility in mind (and doesn't freak out because suddenly the mechanisms aren't behaving AS THEY MUST)

                  Again, there's no way you (as customer) can prove that the machine will behave properly in these unusual/unexpected/UNANTICIPATED scenarios because you can't tell how many such scenarios may exist! What if you pull power now? Or, now?? Or, NOW???

                  One of the devices that I worked on has a ~1T rotating steel disk that is impossible to "stop on a dime". But, it can be slowed pretty quickly and the "access panels" (that keep people out of the production area) are designed so that you have to really try hard to open them fast enough (hydraulic dampers slow the opening, deliberately) to get your hands inside while the disk is slowing. Because the panels open outward, you are effectively pushed away from the machine as you lift them (until they are fully raised). And, you have to physically cross a buffer zone to get TO the disk. And, much of the disk is shrouded so you have to really plan if you "want" to lose a finger!

                  [Of course, if you're strong enough to punch through the panels then you may "get lucky" and find the reward you so desire! ]

                  Another device had 200A (bare, copper) bus bars distributing power to the various subassemblies inside. Short them with a screwdriver and the tip of the screwdriver disappears. <shrug> "Next..." (you learn to remove all jewelry, belt buckles, metal clothing fasteners, metal eyeglass frames, etc. when working in such devices)

                  The tech support person main concern is why the computer controller is doing the rebooting in the first place
                  Yeah, and I'm sure he says "That can't happen"... or "That shouldn't happen". To which you gleefully reply, "But it IS!" Something is obviously deficient in their design. If they are relying on the reboots not being POSSIBLE, and THAT is how they are guaranteeing "safety", I suggest they read up on some of the more colossal failures that also "couldn't (or shouldn't) happen" -- but did!

                  Which I agree with that but I do not think that this is only problem or the hole answer to this problem

                  Or I could be wrong
                  As I said, if they are relying on the controller "staying sane" in all possible scenarios in order to provide the safety mechanisms, then they have to take steps to ensure that is ALWAYS the case.

                  IME, this is not possible -- esp if the controller runs software of any kind. You have to rely on immutable hardware mechanisms for those sort of protections.

                  [Note that the device that is RECEIVING the START/STOP commands probably ALSO has software inside. So, you can't rely on it for your safety, either!]

                  If your concern is for your personnel/safety, just arrange for a disconnect to interrupt the main power to the machine. Remember, the machine MUST be able to survive a power failure -- because power fails EVERYWHERE, sooner or later! (however, you can't then get lazy and abuse that "safety mechanism" as a convenient "on/off" switch!)

                  Comment


                    #10
                    Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                    Originally posted by Curious.George View Post

                    [Note that the device that is RECEIVING the START/STOP commands probably ALSO has software inside. So, you can't rely on it for your safety, either!]
                    Very good point


                    Originally posted by Curious.George View Post
                    If your concern is for your personnel/safety, just arrange for a disconnect to interrupt the main power to the machine. Remember, the machine MUST be able to survive a power failure -- because power fails EVERYWHERE, sooner or later! (however, you can't then get lazy and abuse that "safety mechanism" as a convenient "on/off" switch!)
                    The “E” STOP switch is hooked to a-safety relay and dose stop the machine in it tracks

                    The operator of the machine has been told that IF the machine is going through a reboot that is to hit “E” STOP


                    Also not to leave the machine running while doing something else which has been done all the time before

                    Until we figure out what is the problem with this machine

                    The tech support person thinking is that the hard drive is what is giving the problem

                    I am not sure if this really the problem or not we will see
                    Last edited by sam_sam_sam; 12-05-2018, 05:21 AM.
                    9 PC LCD Monitor
                    6 LCD Flat Screen TV
                    30 Desk Top Switching Power Supply
                    10 Battery Charger Switching Power Supply for Power Tool
                    6 18v Lithium Battery Power Boards for Tool Battery Packs
                    1 XBox 360 Switching Power Supply and M Board
                    25 Servo Drives 220/460 3 Phase
                    6 De-soldering Station Switching Power Supply 1 Power Supply
                    1 Dell Mother Board
                    15 Computer Power Supply
                    1 HP Printer Supply & Control Board * lighting finished it *


                    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                    2 Hem Saw Computer Stack Board

                    All of these had CAPs POOF
                    All of the mosfet that are taken out by bad caps

                    Comment


                      #11
                      Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                      take it out and scan it for errors with a usb caddy, psu not filtering the noise from the motors would be my first suspect.

                      Comment


                        #12
                        Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                        Find the device that is closest to the actuators (let's call that a "motor driver" vs. the "system controller"). See if it has any "inhibit" inputs that you can wire to the limit switches (even if it means adding another set of switches to ensure you don't compromise the existing wiring/connections on the present switches).

                        Imagine each motor having a "driver" that is commanded (START/STOP) by the "system controller". If that driver has an inhibit function, then you can wire the limit switch(es) to the inhibit control and cause the mechanism to stop whenever it drives to the limits.

                        Ideally, there is an inhibit for each direction of travel (otherwise, if either switch is hit, then ALL motion stops, in that axis -- meaning you can't move the mechanism OFF of the limit switch!)

                        The “E” STOP switch is hooked to a-safety relay and dose stop the machine in it tracks

                        The operator of the machine has been told that IF the machine is going through a reboot that is to hit “E” STOP
                        Yes, but this should only be an EMERGENCY response. Like the circuit breakers in your home shouldn't be routinely used as "light switches".

                        The tech support person thinking is that the hard drive is what is giving the problem

                        I am not sure if this really the problem or not we will see
                        Copy disk to another new disk. Test.

                        A system that has a disk drive in it is just shooting craps with reliability. Even if the drive never "fails", it is still a non-deterministic device. You can't KNOW how long it will take to read (or write) any particular datum on the medium. So, how can you guarantee a "timely response" to some real-world event (like running into a limit switch).

                        Arguing that the disk drive "should be fast enough" is like saying the driver of the car should be fast enough to slam on the brakes before *ss-ending the vehicle in front of him... yet, amazingly, it happens all the time!

                        Even if the actual disk is found not to be the problem, there's no guarantee that the disk SYSTEM isn't to blame. It always looks easy to just piece together a system from COTS "building blocks". But, that shifts the design effort into understanding how each of those blocks can fail YOU -- despite still appearing to meet their original specifications ("Well, you're not supposed to USE it that way...")

                        Have your legal department see what sort of leverage they have over teh supplier. Perhaps threaten them with a lawsuit over "lost/damaged materials" or other material losses. Make them think about whether it's cheaper to fight in court (AND lose a customer as well as the bad press that said customer can spread about their product) or just fix the problem.

                        And, have all of your correspondence in writing so they're on the hook in the event something REALLY BAD happens ("You were notified of this potential problem and didn't take steps to remedy it")

                        Comment


                          #13
                          Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                          This machine is not a safe design if it relies entirely on a PC and the OS for control logic. It's missing supervisory hardware and software that operates entirely outside of the PC.

                          What happens when bolts are sheared off and the cutter is still running? If it can break loose and drive across the floor then I would be very afraid
                          It's one thing for a machine to wreck itself, but totally different if it can hurt an operator.

                          You can't go to the manufacturer and demand they make it safe, it doesn't work like that. What safety standard applies to the machine? Usually small manufacturers have nothing formal in their products.

                          If the machine hurts anyone and you have changed any safety system, then you could be held liable. You have to be careful about it.

                          I would fix the crappy PC, see if the limit switches and E-stop are working properly. Then add a watchdog to shut off the machine if the PC hangs or reboots.

                          There are PC Watchdog Cards that will disable something or auto reboot if hung.
                          But they need a small program running to generate a heartbeat, that should be part of the control program i.e. the machine program hangs but the heartbeart program keeps running, so limited usefulness.

                          B&B Electronics used to offer PC Watchdog Timer Card Models: ATRWDT and ATxWDT
                          Berk PC Watchdog but expensive.
                          Or just make something with an IC.

                          Comment


                            #14
                            Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                            Originally posted by redwire View Post
                            You can't go to the manufacturer and demand they make it safe, it doesn't work like that. What safety standard applies to the machine? Usually small manufacturers have nothing formal in their products.
                            Lawsuits are the practical enforcement mechanisms. But, they rely on you having damages (injury, down time, etc.). Simply notifying the manufacturer of your perceived problems with the equipment puts them on notice. Of course, at the same time, your employees now can claim that YOU were aware of the problem and allowed the machine to remain in use.

                            But, these posts (to a diligent attorney) already indicate "that boat has sailed".

                            If the machine hurts anyone and you have changed any safety system, then you could be held liable. You have to be careful about it.

                            I would fix the crappy PC, see if the limit switches and E-stop are working properly. Then add a watchdog to shut off the machine if the PC hangs or reboots.
                            Bwah-ha-ha... and THAT doesn't constitute "changing any safety system"?? Esp in light of the fact that the machine appears to RELY on the software to implement those interlocks?

                            Twist the vendor's arm (hence dragging "Legal" into the mess). If its a "new" machine (recent purchase), threaten to "send it back".

                            If it's a machine you've had on site for a while, then you're faced with three choices: get the manufacturer to fix the problem and recertify the machine as "safe" or take the machine out of service and look for a replacement from another vendor or assume the responsibility for ensuring the machine's safety yourself. There's a reason you want to do business with bigger companies (vs. garage shops) -- they have deeper pockets and more at stake (in a lawsuit).

                            We designed a PLC based process control system for a client many years ago. Client then "appropriated" the design for his own use (all COTS "modules"). While we were peeved at the loss of those follow-up sales, we were also off the hook for any problems/losses they encountered with their "copies". And, not obligated to provide them with any updates/improvements (even on the first item sale) -- that they could then incorporate, by duplication, into their other copies.

                            It's a simple economic question: how much are you willing to risk (and what are the chances of that risk) vs. the value of what you'll have on-hand.

                            Comment


                              #15
                              Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                              Let explain something about the servo drives that move the machine if the two bolts shear off it will not let machine run any more

                              Also when I made comment about safety I was saying this in general terms not meaning that anyone could get hurt

                              I made the comment base on the rule about robotics in general

                              That it should not hurt anyone
                              That it should not destroy it self or any other equipment

                              I do not remember all the rules

                              I can tell you that tech support is looking to the matter and they are getting there engineering department involved with this matter as well

                              We might looking at doing a machine upgrade as well
                              I have told them that they are on borrowed time with the setup of this machine as it is now it is 10 years old by the way
                              Last edited by sam_sam_sam; 12-05-2018, 02:07 PM.
                              9 PC LCD Monitor
                              6 LCD Flat Screen TV
                              30 Desk Top Switching Power Supply
                              10 Battery Charger Switching Power Supply for Power Tool
                              6 18v Lithium Battery Power Boards for Tool Battery Packs
                              1 XBox 360 Switching Power Supply and M Board
                              25 Servo Drives 220/460 3 Phase
                              6 De-soldering Station Switching Power Supply 1 Power Supply
                              1 Dell Mother Board
                              15 Computer Power Supply
                              1 HP Printer Supply & Control Board * lighting finished it *


                              These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                              1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                              2 Hem Saw Computer Stack Board

                              All of these had CAPs POOF
                              All of the mosfet that are taken out by bad caps

                              Comment


                                #16
                                Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                                Originally posted by sam_sam_sam View Post
                                We might looking at doing a machine upgrade as well
                                Ask them, specifically, how the machine handles <...> (fill in a variety of "extraordinary" -- but highly possibl! -- scenarios).

                                E.g., can power to the computer/controller fail while power is still available to the actuator drivers? (can someone purposely or accidentally "unplug" power or comms cables and subvert the safeties in place?)

                                Keep in mind that employees may be motivated to bypass safety interlocks -- esp if they make it "inconvenient" for them to do their job or impact their overall productivity (e.g., if paid for "piece work").

                                At one of the manufacturing facilities where I worked, an employee bypassed the guards that were intended to ensure his hands were out of the way when the stamping machine crunched down to deform the bar of steel he was charged with making. One day, it took his finger off -- and was (of course) completely unaffected by the harm it had done him!

                                (Of course, that's why OSHA wants to inspect accident scenes -- was the company at fault? What role did the worker play in his accident? etc.)

                                Comment


                                  #17
                                  Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                                  One final note

                                  On this subject

                                  I would like to thank everyone who has made comments on this post and as far as I am concerned this has been looking into and is closed

                                  I would like to close this matter for now

                                  When the problem with machine has been resolved I will let you know what the outcome is and what was done to fix the problem
                                  9 PC LCD Monitor
                                  6 LCD Flat Screen TV
                                  30 Desk Top Switching Power Supply
                                  10 Battery Charger Switching Power Supply for Power Tool
                                  6 18v Lithium Battery Power Boards for Tool Battery Packs
                                  1 XBox 360 Switching Power Supply and M Board
                                  25 Servo Drives 220/460 3 Phase
                                  6 De-soldering Station Switching Power Supply 1 Power Supply
                                  1 Dell Mother Board
                                  15 Computer Power Supply
                                  1 HP Printer Supply & Control Board * lighting finished it *


                                  These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                  1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                  2 Hem Saw Computer Stack Board

                                  All of these had CAPs POOF
                                  All of the mosfet that are taken out by bad caps

                                  Comment


                                    #18
                                    Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                                    Originally posted by Curious.George View Post
                                    Ask them, specifically, how the machine handles <...> (fill in a variety of "extraordinary" -- but highly possibl! -- scenarios).
                                    This will happen if and when we do the machine upgrade

                                    Yes you can count on the fact that this will ask and to the point that they are going to have show me that it works

                                    Meaning that if the computer controller stops working while the machine is moving that machine comes to a complete STOP
                                    Last edited by sam_sam_sam; 12-05-2018, 02:26 PM.
                                    9 PC LCD Monitor
                                    6 LCD Flat Screen TV
                                    30 Desk Top Switching Power Supply
                                    10 Battery Charger Switching Power Supply for Power Tool
                                    6 18v Lithium Battery Power Boards for Tool Battery Packs
                                    1 XBox 360 Switching Power Supply and M Board
                                    25 Servo Drives 220/460 3 Phase
                                    6 De-soldering Station Switching Power Supply 1 Power Supply
                                    1 Dell Mother Board
                                    15 Computer Power Supply
                                    1 HP Printer Supply & Control Board * lighting finished it *


                                    These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                                    1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                                    2 Hem Saw Computer Stack Board

                                    All of these had CAPs POOF
                                    All of the mosfet that are taken out by bad caps

                                    Comment


                                      #19
                                      Re: Metal Cutting Table —&gt; run-a-way machine while doing homing routine

                                      Could you not add a brake? Power gets cut from breakout and mechanical brake applied. Common z axis add on with ball screws and rails in hobby machines.

                                      If you can transfer the software share and files to a new pc atleast for testing I'd try that first. After ground checks.

                                      Also what kind of metal cutting machine? Plasma , edm, water, mill or lathe?
                                      Last edited by junktv; 12-05-2018, 10:42 PM.

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