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  1. #11
    Quote Originally Posted by dazp1976 View Post
    You need to. Or any other kind of 'switch'.
    You can't directly connect a breakout board / controller output to vfd FWD / DCOM.
    It simply does not work (or will break them) .
    My favorite Quote that you maybe should think about.?

    "Better to remain silent and be thought a fool, than to open one's mouth and remove all doubt.!"
    -use common sense, if you lack it, there is no software to help that.

    Email: dean@jazzcnc.co.uk

    Web site: www.jazzcnc.co.uk

  2. The Following User Says Thank You to JAZZCNC For This Useful Post:


  3. #12
    I most definitely don't want to upset anyone, and I appreciate the difficulty of dealing with questions on the forum when you don't know the background of the person asking. In particular, very few participants here understand the first thing about electrickery and questions tend to be of the general form, "Where do I stick the red wire?" However, in my case with a degree in electronic engineering, many years playing with building amateur radio kit, and having built a couple of CNC routers and done a brain transplant on them more than once, I had looked at the UCBB output circuitry (usefully given in its manual, although the AXBB manual didn't seem to do the same thing) and noted the output MOSFET 2A/50V rating. I was really just looking at whether someone had internal (literally) info on the HY VFD ground isolation. I would have been reassured to hear something that backed up the checks I was going to do anyway (and which suggest that there is ground isolation on the DCM and digital input pins). I'm one of those people who find it difficult to accept a "do it this way, don't do it that way" without a technical explanation. Even if many people asking questions here do want exactly a "tell me how to do it, don't bother explaining!" approach!

    If I were doing this job from scratch, I would have designed in a relay (for belt and braces rather than necessity) and allowed space for it in the control box. However, as this is a brain transplant job, adding a relay as well as having two boards to replace the one original would be a bit of a fiddle that I would rather avoid. I'm using the UCBB rather than AXBB because I want to retain the 24V signalling in the control box rather than go to 5V.

    Jazz - out of curiosity, I'm assuming that you have used the UC300/HY VFD combination, so how would you normally switch the HY digital inputs? Depends on BOB used, maybe?

    Oh, and if you want a laugh at my expense - after installing the UC300/UCBB and wiring it all together, installing the latest version of UCCNC (and even noting a minor bug in the diagnostic screen display) and configuring it, I can't get the steppers to move... I've probably forgotten a ground wire somewhere or something stupid like that. There's nothing like confessing to a problem like this to make the answer leap out at you, so I'm off to the workshop with my oscilloscope to find this week's stupidity!
    Last edited by Neale; 11-05-2022 at 03:48 PM.

  4. #13
    Quote Originally Posted by JAZZCNC View Post
    My favorite Quote that you maybe should think about.?

    "Better to remain silent and be thought a fool, than to open one's mouth and remove all doubt.!"
    Hey. I'm only going on what someone else did and broke their axbb-e.
    The bbe is basically the 300eth and a smaller ucbb.
    So



    Edit: although 1 side of it is non-isoltated. Could that be why.
    Last edited by dazp1976; 11-05-2022 at 05:36 PM.

  5. #14
    The reason I would use a relay is because when I worked in industry that was the standard method for a reason and I liked it, same thing with PLC's
    It was found that if a fault developed it was cheaper, easier, quicker, to replace a small plugin relay than a VFD, PLC, or the device controlling it.
    Galvanic isolation with a set of "volt free" contacts would always be my solution, there can be some undesirable and unforseen results by connecting supposed "earths" together.
    Spelling mistakes are not intentional, I only seem to see them some time after I've posted

  6. #15
    Quote Originally Posted by EddyCurrent View Post
    The reason I would use a relay is because when I worked in industry that was the standard method for a reason and I liked it, same thing with PLC's
    It was found that if a fault developed it was cheaper, easier, quicker, to replace a small plugin relay than a VFD, PLC, or the device controlling it.
    Galvanic isolation with a set of "volt free" contacts would always be my solution, there can be some undesirable and unforseen results by connecting supposed "earths" together.
    I'm not that "fool"ish then, yes?.
    I tend to use optocoupler modules instead of relays for switching DC components lately.
    Can get them for peanuts.

  7. #16
    Certainly in an industrial environment, the situation is different. For one thing, you are not necessarily in control of where things are used and given that there might be a mix of three-phase supplies plus single-phase supplies coming from different phases, "ground" potentials all over the place, then relying on a connection between grounds on two bits of kit might not be a good idea. After all, it's one reason why ethernet is galvanically isolated. There is also the "make it idiot-proof" requirement. In my case, all my kit is being fed off a single 13A multiway extension off a single 13A socket, and I am the only idiot allowed to use the kit! After all, similar reasoning says that I haven't fitted door-open trips on my control box where that would be entirely unacceptable in industry. A relay is definitely the proper way to go, but I've run out of mounting space and I don't have one to hand. In addition, the UCBB outputs are each opto-isolated on the board and feed distinct mosfet output devices rated well above my requirements, so while a fault might take out one channel, I have spares. And a VFD fault major enough to cause such a failure is likely to be a major VFD failure anyway.

    For those who might be wondering, the digital inputs on the HY VFD are sufficiently isolated that a direct connection to the UCBB works fine. I have had the thing running this evening. Just like the analogue output from the UC300ETH which connects to the VFD analogue in and ACM pins. I mentioned above that I was going to need a 16-pin IDC connector to pick up the analogue signal but as I finished typing that entry, I suddenly realised that the 2.5mm pin spacing, etc, matched that used on PC motherboards for USB connections, etc, and I was able to find a surplus connector that I could use. I think that this is the equivalent of the connectors that someone else (forgive me for forgetting who at this point) mentioned - thanks for reinforcing my own thoughts!

    But I have to confess that I did shoot myself in the foot with the UCBB - stepper driver connections. I was replacing a motion controller with differential outputs, but for convenience wanted to reuse the UTP cables between the two devices. I used the "solid" colours for the signals and just trimmed back the "stripe" connections, and made up a set of jumper cables to provide +5V to the drivers. Bit of a shame that without thinking, I "assumed" that the solid colours connected to the -ve side of the stepper driver inputs so having removed the "stripe" connections I replaced them with the +5V feed. I really should have looked at the markings on the drivers as I had the polarities reversed and it took me most of the evening to realise it. I knew it was something silly that I had done, but didn't imagine just how silly...

    You are allowed to fall off chairs laughing

  8. #17
    Quote Originally Posted by dazp1976 View Post
    Hey. I'm only going on what someone else did and broke their axbb-e.
    The bbe is basically the 300eth and a smaller ucbb.
    So
    Exactly why you should remain silent or at least think before telling people that something can't be done like you are an authority on it when really you have no clue or experience yourself other than something you read.!

    The fact it's not the best idea has nothing to do with anything, it can be done and that's what was basically being asked but luckily Neale is no duck egg so knows better but if this had been a new user then your post could have sent them off in directions they didn't need to go. If you or anyone is not 100% on electrical matters they should either state this when dishing out advice or keep quiet.

    Quote Originally Posted by Neale View Post
    But I have to confess that I did shoot myself in the foot with the UCBB - stepper driver connections. I was replacing a motion controller with differential outputs, but for convenience wanted to reuse the UTP cables between the two devices. I used the "solid" colours for the signals and just trimmed back the "stripe" connections, and made up a set of jumper cables to provide +5V to the drivers. Bit of a shame that without thinking, I "assumed" that the solid colours connected to the -ve side of the stepper driver inputs so having removed the "stripe" connections I replaced them with the +5V feed. I really should have looked at the markings on the drivers as I had the polarities reversed and it took me most of the evening to realise it. I knew it was something silly that I had done, but didn't imagine just how silly...

    You are allowed to fall off chairs laughing
    I've done far stupider and costly cocks so don't go into hiding over it, your not the first and won't be the last to do it.

    Quote Originally Posted by Neale View Post
    Jazz - out of curiosity, I'm assuming that you have used the UC300/HY VFD combination, so how would you normally switch the HY digital inputs? Depends on BOB used, maybe?:
    Sorry, Neale, I missed this.!
    I always control a relay Neale for a number of reasons, isolation being one but I can also control several things at the same time the spindle turns on ie water pump etc.
    Last edited by JAZZCNC; 12-05-2022 at 08:00 PM.
    -use common sense, if you lack it, there is no software to help that.

    Email: dean@jazzcnc.co.uk

    Web site: www.jazzcnc.co.uk

  9. #18
    Quote Originally Posted by JAZZCNC View Post
    The fact it's not the best idea.
    Question. Talking of switching drive directions:
    Servo drive. I'm using a small opto module to switch the digital input on/off for cw/ccw - m3/m4.
    It's 5v in 24v out direct connected to uc300eth port #5. Works great, however.
    What do you think about using the cw/ccw inhibit along with it as an extra measure?. (more just because it can maybe).
    So:
    ccw=on - cw=inhibit. M3.
    cw=on - ccw=inhibit. M4.
    I'd use the opto module as a series connection to 2 outputs M3+CWL, M4+CCWL.

    Worth bothering or not?.
    Thnx.

  10. #19
    Quote Originally Posted by dazp1976 View Post
    Question. Talking of switching drive directions:
    Servo drive. I'm using a small opto module to switch the digital input on/off for cw/ccw - m3/m4.
    It's 5v in 24v out direct connected to uc300eth port #5. Works great, however.
    What do you think about using the cw/ccw inhibit along with it as an extra measure?. (more just because it can maybe).
    So:
    ccw=on - cw=inhibit. M3.
    cw=on - ccw=inhibit. M4.
    I'd use the opto module as a series connection to 2 outputs M3+CWL, M4+CCWL.

    Worth bothering or not?.
    Thnx.
    For what purpose.? I see none as it can only spin in one or the other direction never both together so no need. And if the servo is clever enough then it would throw either a fault or inhibit itself if both inputs become active at the same time.

    I'm guessing this is for a spindle drive.? In which case, if your hell bent on using the inhibits use them when changing tools either via a switch or on-screen button.!
    -use common sense, if you lack it, there is no software to help that.

    Email: dean@jazzcnc.co.uk

    Web site: www.jazzcnc.co.uk

  11. #20
    Quote Originally Posted by JAZZCNC View Post
    I'm guessing this is for a spindle drive.? In which case, if your hell bent on using the inhibits use them when changing tools either via a switch or on-screen button.!
    Yes, spindle.
    I didn't think it was worth the bother.
    Thought I'd ask the pro anyway.

    The tool change idea sounds a good one.
    Ta.

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