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  1. baxtersdad

    RS Linx (Fix)

    Had occasion to pick up a nice trick for Linx. After a sudden disappearance of a certain PLC, which had been showing in RS Who, a customer support engineer suggested I remove two files in the C:\Program Files\Rockwell Software\RSCOMMON directory. They are both named Harmony, one extension .hrc...
  2. baxtersdad

    Centrifuge AC Induction Motor Requireing 30 Starts Per Hour

    I believe that the tables to which you refer are based on full voltage starting with the attendant high currents/heating of that starting method. The VF drive should be able to operate the motor at 100% torque throughout the acceleration period with much lower heating than full voltage starting...
  3. baxtersdad

    PID output staying High when SP = 0

    With at deadband of 30 you tell the pid to take no action until the error > 30. Simple fix is to compare the PV/SP for this condition and when it exists momentarily force the PID instruction to manual and over write the output register with zero. Make sure to position your logic so that it...
  4. baxtersdad

    Wye-Delta Starting Under Load

    Wye-Delta starting is primarily used to start high inertia loads. A loaded wood shredder would probably qualify.. Problem is that the motor torque is reduced to 1/3 of locked rotor torque when compared to direct on-line start. If the load torque requirement exceeds this value then you have a...
  5. baxtersdad

    Wire voltage rating

    Thanks both. Looks like the heating effect is in control...
  6. baxtersdad

    Wire voltage rating

    Given a low voltage cable rated at 600VAC, what would be the maximum allowable DC voltage on which the cable could operate and remain within its design withstand, 600VDC or 850VDC? My question comes from a VFD commom bus application where two drive DC buses are interconnected. A 480VAC VF drive...
  7. baxtersdad

    Two analogs to one VFD

    I need to supply a speed reference (4-20MA) to a vfd from two separate plc systems (4-20 ma outputs) for redundancy. Would prefer to have no user input required to make the selection. Considered using a high-select analog module but this would require a separate loop supply which is...
  8. baxtersdad

    Reversing Rotation of a 3-Phase Motor

    The standard method to change direction on a six lead motor is to interchange two of the three phases. With six leads, you have to do it in two places. You would interchange T1-T2 and T6-T4. This will give you the result you seek.
  9. baxtersdad

    Color codes

    NFPA 79, pp 10.2.2.7 Gives Blue, Black, White or Grey as acceptable colors for a reset PB. When they act as a stop, it requires Red.
  10. baxtersdad

    Status Bit when using latching outputs

    Try using the first scan bit to unlatch the latched output. This is a "one-shot" bit which is asserted during the first program pass after powerup.

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