Mesa board encoder and U3K

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23 May 2024 20:45 - 24 May 2024 01:08 #301256 by Dave2024
Hows it going.  So I was wondering if anyone could help me out on this project of mine where I’m trying to install and configure an encoder for the first time on a spindle?  The reason for wanting to do this originally was that when using the spindle in PWM it only had the option for 5 different speeds and they all acted weird with horrible oscillations to the point that the speeds were unusable for anything.  Anyways here’s a list of the hardware, software and problems I’m having. 

Hardware:               
    Mesa 7996s - Motion Control Board               
    Ultra3000 – Spindle Drive               
    AMT312Q – Encoder               
    Generic 300v BLDC Motor – Spindle Motor               
    AMT-PGRM – Encoder Programming Module               
    RaspberyPi 4 – Computer System Interface               
    HY1803D – DC Power Supply 

Software:               
    LinuxCNC – Operating System               
    UltraWare – Spindle Drive Configuration Software               
    AMTViewpoint – Encoder Configuration Software

Issues/Problem:

1.      The fist problem and it may not even be a problem is when I energize the U3K both the Green and Red led's are blinking.  I looked up what this message indicates and in the manual it says that unit is ‘Self Testing’ or ‘Self-test in progress’ and that the resolution to the problem is to wait.  I have left the drive on all night once and in the morning both the led's were still blinking.  Is it possible this is a bad U3K unit or is this typically how they behave when it has not received any input?

 2.      My second problem is in Pncconf after I set one of the axis outputs to become Spindle Step/Dir then continue through till I get the Spindle Motor configuration page and click the ‘Open Loop Test’ button I get the error: “You must designate a ENCODER / RESLOVER signal and an ANALOG SPINDLE for this test.  I thought open loop didn’t require any encoders or resolvers though?  Anyways I’m really confused as to how to set this up to at least generate a test signal to see if it stops the blinking led's like in issue 1 with the U3K.   

3.      Third is more of an electrical type issue but the encode that I’m planning on installing requires calibrating or “Zeroing” and the procedure it calls for is that I’m to apply positive voltage the Phase 1/U wire and ground to the Phase 2/V wire and leave the Phase 3/W wire disconnected.  Doing this should cause the motor to rotate slightly and then lock into a fix position.  With the motor locked/braked I am then supposed to send the encoder the calibrate to Zero command using the AMTViewpoint software.  This should successfully calibrate the encoder to synchronize and work with the motor.   My problem with this is I don’t have enough electrical background knowledge to figure out what a safe voltage and amperage is to apply to the motor.  The last thing I want is to burn up the windings.  I do have a HY1803D DC power supply that I can attempt it with that’s adjustable 0-18V and 3A max.   Would this power supply be efficient enough to lock the motor and what would be a safe setting to do it at?   


Anyways if anyone is familiar with any of the hardware or programs I’m working with please respond to my post id really appreciate it or any input or assistance on what I’m trying to do here.  Thanks
 
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Last edit: 24 May 2024 01:08 by Dave2024.

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24 May 2024 01:39 #301271 by tommylight
Since when does Mesa manufacture a 7996S board? :)
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1. that should usually take 1-maybe if i stretch it-5 seconds, so something is not OK
2. Prabaly still not implemented to use step/dir for spindle, so for testing maybe use it as axis/joint
3. that power supply should be OK for the test, set it to 18V and limit the current to 1A, turn it on while holding the motor shaft by hand, if it moves a bit and locks so it takes a bot of effort to move it, continue to calibrating it, if it is to weak to notice - raise the current to 3A and try again.

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24 May 2024 17:02 #301333 by spumco
Replied by spumco on topic Mesa board encoder and U3K
Dave2024,

Do this in steps:
  • Encoder on motor
    • Install encoder
    • Program encoder PPR with AMT software and programming cable.  The USB cable will power the encoder.
      • Determine what the max pulse frequency can be (based on U3k input ceiling and max RPM) and set the encoder PPR to something that gives you a bit of headroom.  1024 or 2048 should be fine, but you may need to go lower if you get some noise.
    • Auto-phase the encoder simulated hall signals
      • Follow the YT videos from AMT/CUI.
      • A 9v battery works well to get one of the phases locked in position.  Just connect one of the 3 wires to 9v+, and another wire to the negative terminal.  The rotor will jump and lock in position.  Disconnect the battery and keep the rotor from turning with a bit of tape or something while you run the AMT auto-phase process.
  • Set up U3k to work with encoder & motor (Ultraware)
    • Power up the U3k and connect via Ultraware.  This will allow you to determine (via the diagnostic features) what is causing the status LED's to do what they're doing now (perpetual self-test)
    • You MUST have a 'crossover' cable or crossover adapter to connect the USB to serial cable adapter to the U3k.
      • Search for "DB9 NULL MODEM ADAPTER" on Amazon or similar suppliers
      • Without the crossover you won't be able to connect your PC/Ultraware to the drive, no matter what the COM port settings - period.
    • Use Ultraware to configure motor & encoder parameters
      • Create a new motor project and enter the values from the BLDC data plate.  You will have to guess on some of those (rotor inertia, etc.) since you don't have a detailed datasheet.
    • Verify U3k can 'see' the encoder signals with the ultraware motor monitoring function
      • If the U3k isn't receiving the encoder counts/signals, you can't proceed until you sort this out.
    • Optional - the U3k doesn't need hall signals.  It has an optional mode where on first enable after power-up the drive will wiggle the motor slightly to determine the winding phase(s) relationship to the encoder.  This is sometimes called 'wake & shake' and is used if a motor doesn't have commutation signals.  Search for 'self-sensing' in the Ultraware manual.
  • Test the motor/encoder via Ultraware
    • If you've got everything sorted to this point, you can use Ultraware to move the motor in both positioning and velocity modes.
    • You will need to provide full bus voltage to the U3k from this point on.
  • Program U3k for use with LCNC
    • Once the motor & U3k are working together you can program the command mode (step & direction) and drive IO signals.  We can go over that stuff in detail once you get there.
The following user(s) said Thank You: tommylight

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