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  1. #51
    I’ve been having a look at what I have from the old system and if I could use any of it for the E stop circuit and how to go about it. Just wanted your opinions to see if this would work and not cause any damage to anything… or if its just stupid!

    I’ve got at the moment a phase and neutral from the 3 phase supply coming into the cabinet that go into fuses, which then go into a large contactor. I was wondering if I could use that contactor set up with a momentary switch, E stop, and relay (which I have from the old setup which are all rated to 600Vac). Then on one of the switched terminals from the contactor could I then feed the 230Vac supply to the transformer which will power the drivers, and on another the supply that goes up to the spindle start button.

    With the spindle I should mention it is currently still set up as it would have been when in manual operation. So it is not linked to the CNC side of the machine other than it used to run through a relay so you could only turn the spindle on when the pendant was powered up.

    Just reading through what I have written, I guess I could just run the spindle feed through the same relay as the e stop and just switch the 230 through the contactor…

    Hopefully someone can make sense of my awful explanation!

  2. #52
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 3 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    Officially all user buttons should be low voltage (IIRC in this context, it's sub 60V), which is why most control systems use 24VDC.

    In an industrial setting, you would normally use a dedicated safety relay (essentially a relay with multiple contacts, that all get monitored, and should any fail, the relay won't activate).
    However what happens when an E-stop gets pressed, is down to risk assessment. An E-stop should bring the machine to a stop in a safe and controlled manner. With modern servos, you would normally do that by triggering the servo drives fast stop input, then a few seconds later, remove drive power. This means the drive should bring the servo to a fast stop, then power down. If you simply cut power, the servo can keep moving then freewheel to an uncontrolled stop.

    However, as it looks like you're using older DC servos, then you have to consider a servo runaway failure.
    DC servos is one setup where I would seriously recommend where limit switches are part of the e-stop circuit, and the E-stop kills the drives as quickly as possible, as you really don't want a servo running past the limit switch under full power.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

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  4. #53
    Makes sense, hadn't thought of it like that! Maybe the E stop button I have was rated to 60V and not 600V then, need my eyes checking!!

    Thanks for the info, better get back to the drawing board on this one then!

  5. #54
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 12 Hours Ago Has been a member for 6-7 years. Has a total post count of 417. Received thanks 61 times, giving thanks to others 10 times.
    Yo JimJam - wondering how you are getting on - I expect you will have been cutting chips by now!

    Let us know what you are up to on this!

    Murray

  6. #55
    Hi Murray,

    Still making some slow progress! Back at work now so I haven't had too much time to play with it.

    Waiting on a few last electricary bits to arrive then I should have everything I need to get it going in some basic form! would be nice to see a bit of movement from it soon!

    Being back at work means I might be able to knock up the adaptor bits I need to mount the encoders to the motors as well.

    Did you have much trouble getting your motors and drivers set up and working properly? I forgot to order the USB programming stick for the drives, so it would be lovely if they just worked out the box. I have a sneaking suspicion that couldn't be further from reality though....

  7. #56
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 12 Hours Ago Has been a member for 6-7 years. Has a total post count of 417. Received thanks 61 times, giving thanks to others 10 times.
    They may just work out of the box after a fashion (I don't recall) but it's unlikely the PID (tuning) settings will be magically anywhere near optimum.

    Might be sensible to order a USB thing now, as you are going to need it at some point. It's their own interface as far as I can see so you can't just reuse something else.

  8. #57
    Yeah it would be silly not to get one for the price, think postage will be more than the costs of it! Just waiting for them to get the payment info to me and It'll be on the way, been about 10 days since I ordered it and not heard from them. hopefully they're doing alright over there!

    Started getting everything mounted up in the cabinet now, changed the layout god knows how many times. The base plate's like swiss cheese now!!

    Got the mounts for the encoders machined up to bolt to the motors, they add a bit more length than I would have liked but I didn't want to start modifying and shortening the motor shafts really so I'll just have to live with it. Once (if) it's up and running I'll make a cover to protect them a bit more.

    Also finished the new pulley mount for the Z axis ball screw. (and yes, I did reassemble the ball screw the wrong way after machining it...that was rather annoying to assemble twice!)

    Starting to get somewhere now though!

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  9. #58
    Muzzer's Avatar
    Lives in Lytham St. Annes, United Kingdom. Last Activity: 12 Hours Ago Has been a member for 6-7 years. Has a total post count of 417. Received thanks 61 times, giving thanks to others 10 times.
    I enquired about buying something small from them once - think it might have been a line driver board - but never got a reply. You might need to give them another nudge until you get a response or you may not see it. Larger orders possibly attract their attention more easily.

    Dunno if you are aware that there is a cncdrive forum - you may be able to contact them through that http://www.forum.cncdrive.com/

    Those housings look the part. Good to have access to decent machines when doing this sort of work.

    Looks as if you actually replaced the Z axis ballscrew / ballnut? Did you enjoy machining the hardened steel? Sparks everywhere?

  10. #59
    Yeah that did cross my mind, the initial order was quite a chunk of money and I had a reply within a few hours.. I'll give the forum a try, thanks for the link.

    Thanks, it certainly makes things easier! Worth taking the extra effort to make them properly, hopefully less head aches with setting them up knowing they are machined properly so the alignment between them should be good.

    I replaced them both in the end, the old screw was cracked and it was an odd size. Also needed new bearings as well so just replaced the lot. Can't beat a bit of hard machining, sparks were disappointing though! It was actually worryingly not that hard if I'm honest... looked to be case hardened around 3mm per side, the rest was really soft...

    I guessed it wasn't going to be amazing quality based on the price, think its was £30 for the screw and nut... we'll see how it does.

  11. #60
    Starting to get somewhere with wiring it all up now, just a quick query before I do something stupid...

    so the wiring instructions for the main plug from the drive to AXBB board are:

    The pinout of the Main connector is listed below:

    1) Step signal input
    2) Direction signal input
    3) Ground for Step and Direction signals (NOT for power)
    4) 5V power input. (if this input is fed then the 7.pin should not be connected!)
    5) Reset (input) and Stop input)
    6) Error (output) and Stop input
    7) DC power + (12V DC input for digital processor)
    8) DC power – (ground for the 12V DC power supply)

    Step 3 says NOT for power, but the wiring diagram shows it connected to the 0V of the 5VDC power supply...
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