MB2 logic levels


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    Default MB2 logic levels

    I am upgrading a machine and have a MB2 on order. It looks like it is geared to 24V logic levels on its inputs. My home and limit switches are optical and can't handle above 12V. Does anybody know if inputs can be lower voltage by jumper selection? also, In the online docs I saw I did not see at what voltage inputs switch from logic 1 to 0.

    Anybody know?

    Thanks

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  2. #2
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    Default Re: MB2 logic levels

    Ok, let me try again:
    I am using an MB2. The specs indicate the inputs can be 5V or 24V. The manual shows a representative circuit of internal 24V feeding through the isolator diode then to a resister (value not indicated) then to the input terminal. When the input is high (no current flowing), the voltage at the input pin will be 24V which will not work with 5V solid state logic.

    How can you hook 5V solid state logic to the MB2 inputs.

    I have sent two requests to the manufacturer with no response.



  3. #3
    Gold Member Jim Dawson's Avatar
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    Default Re: MB2 logic levels

    In looking at the user manual, the inputs are rated at 5 to 24VDC (rather than 5 or 24 V), this is a pretty common industrial input. The inputs are completely isolated from the 24V board power, so you will use an external 5V supply.



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    Community Moderator ger21's Avatar
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    Default Re: MB2 logic levels

    I have sent two requests to the manufacturer with no response.
    Hmmm, he's responded to my questions within a day or so.
    Mine shipped on 11/29/16, and no sign of it yet. Not sure how long it's going to take to get here.

    In looking at the user manual, the inputs are rated at 5 to 24VDC (rather than 5 or 24 V), this is a pretty common industrial input. The inputs are completely isolated from the 24V board power, so you will use an external 5V supply.
    Is that only for the 5 PNP inputs, or for all of them?

    Gerry

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    Default Re: MB2 logic levels

    For the NPN inputs, the manual implies that the pull up voltage is onboard the MB2 and is 24V. So, when the input is in the "off" state, the voltage seen at the input pin will be 24V. The outputs for my optical switches for limit an home are rated at 16V max. Am I missing something?

    You can only have so many pins on the board, but I would sure like to be able to select or at least source the pull up voltage value on an optical input.



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    Default Re: MB2 logic levels

    My guess is your machine has Optocouplers on the board and they can handle a range of voltage from 5 to 24V. Look at the board closely but normally 24V logic is designed so you can have a higher input voltage on sensors like 24V and the other side of the optocoupler is tied to 5VDC so all the voltage going to the logic is limited to 5V or slightly lower. Take a photo of your controller board this is pretty easy to spot.

    Russ



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    Gold Member Jim Dawson's Avatar
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    Default Re: MB2 logic levels

    Quote Originally Posted by ger21 View Post

    Is that only for the 5 PNP inputs, or for all of them?
    In looking at the manual again, it does look like the PNP inputs are the only ones that are isolated out of the box. If the optical sensor is a PNP output, it should be able to connect to the input. It also looks like the board might be able to be modified to isolate all of the inputs, I'm still trying to understand all of the user manual. They reference solder jumpers for modifications, still trying to wade through that.

    I would like to see a link or a part number for the optical sensors. There should be a way to connect it.



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    Default Re: MB2 logic levels

    pages 10,11 in the manual show typical NPN inputs and PNP inputs pretty clear. The most common type sensors are proximity sensors or optical sensors, however you can use plain Jane micro switches as well.


    http://warp9td.com/images/BOB_Vendor...nual%20E12.pdf



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    Community Moderator ger21's Avatar
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    Default Re: MB2 logic levels

    There's a more current manual here:
    http://www.cncroom.com/downloads/MB2...al%20E16R4.pdf

    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

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    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
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    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Default Re: MB2 logic levels

    WOW,
    I really like the MachBob2 board, did not even know it existed. I have the ESS and ended up making three custom boards to handle optical homing sensors, Balluff proximity sensors used for limits, and a differential driver board since my servo amps like differential drivers. They did a nice job on that board. I also have the CNC4PC C25 board which is pretty cheap and does not give you access to the third parallel port. I will probably have to pick up one of these units.

    Russ



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    Default Re: MB2 logic levels

    Yeah, I don't think anyone had ever heard of them until recently. Someone sent me a link on the UCCNC forum, and I've been spreading the word a little. I'm using mine with a UC300ETH and UCCNC.
    It appears that shipping takes quite a while, but the price is reasonable, $20.

    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Default Re: MB2 logic levels

    Looks like the board costs $140 from cncroom.com, did not see any USA sellers on ebay. This does look like a nice clean board. Anyone else buy one of these units?

    Russ



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