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Thread: delta tau

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  1. #1
    Join Date
    Apr 2006
    Posts
    10

    delta tau

    Hello everyone, I'm hoping someone can help me out here. I'm trying to
    set up a delta tau motion controller ( vme bus model in a standalone setup )
    and I'm not having much luck. I have checked all the jumpers on the board
    and I'm pretty sure I have them correct. I can communicate with the
    controller with the pmac software, and have set the I-variables to the
    factory default. The problem is I can't get any response from the DAC's
    ( analog output). When +/- 15v is applied to the card I get about +/- 3.8v
    at the output channels for all the axis, even if the motors are disabled by
    the controller. If a motion command is issued no voltage swing occurs it
    just stays at 3.8v. I have the limit switches and amplifier faults disabled,
    and have toyed with the DAC bias and gain--- still no change. I would
    think that the DAC voltage should be zero if no motion is commanded or the
    motors are disabled am I on the right track?

    thanks in advance for any opinion.

    jeremiah

  2. #2
    Join Date
    Oct 2005
    Posts
    105
    You do have have IX00 = 1 (100,I200,I300...) right?
    Have you tried open loop comand? #1 O50 & O0 (O50 = 50% O0 = off)
    Unless you changed IX69 you will not get 10V you will get about 6V.

  3. #3
    Join Date
    Apr 2006
    Posts
    10
    Thanks for your reply Ron,
    I do have I100=1, and have had I169 at various settings while testing.
    The commands you suggested is how I have been trying to get a response
    from the DACs. Come to think of it, I only have the end of travel limits
    disabled for motor #1. Do you suppose the motor could be disabled from the
    other axis that don't have their limits disabled? When I view the motor status
    screen in PMAC executive (dos version) it shows the amplifier as being
    enabled, but now I wonder if this is true. Perhaps it only shows it disabled
    if it is from it's own limits. I'll check this later.
    thanks again.

  4. #4
    Join Date
    Oct 2005
    Posts
    105
    What do you have I125 set at?

  5. #5
    Join Date
    Apr 2006
    Posts
    10
    Ron it's set at 49152.

  6. #6
    Join Date
    Oct 2005
    Posts
    105
    I that might be part of the problem.
    You should have I125 = $32C000 or 3325952

    From manual

    Overtravel Limit Use Bit: With bit 17 equal to zero – the normal case – the +/-LIMn inputs must be held low to permit commanded motion in the appropriate direction. If there are not actual (normally closed or normally conducting) limit switches, the inputs must be hardwired to ground.
    If bit 17 (value $20000, or 131072) is set to one (e.g. I125=$2C000), Motor x does not use these inputs as overtravel limits.

    Amplifier Fault Use Bit: If bit 20 of Ix25 is 0, the amplifier-fault input function through the FAULTn input is enabled. If bit 20 (value $100000, or 1, 048,576) is 1 (e.g. 1125=$10C000), this function is disabled. General-purpose use of this input is then possible by assigning an M-variable to the input.

    Action-on-Fault Bits: Bits 21 (value $200000, or 2,097,152) and 22 (value $400000, or 4,194,344) of Ix25 control what action is taken on an amplifier fault for the motor, or on exceeding the fatal following err limit (Ix11) for the motor:

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