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<< Click to Display Table of Contents > Pull-up / pull-down |
  
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<< Click to Display Table of Contents > Pull-up / pull-down |
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With the help of an additional resistor, the tri-state signals of the card can be led into a safe state.
Such a resistor can be wired as pull-up or pull-down resistor. A pull-up configuration is useful in combination with active low signals and a pull-down configuration with active high signals.
Pull-up/pull-down resistors are only relevant for signals which have a tri-state during booting. For the USC cards, signals with a tri-state are:
•Laser Signals (Laser_Gate, Laser_A, Laser_B)
•Laser_Port
•Digi_Outs (USC-2/-3 only)
•Stepper_Outs(USC-2/-3 only)
It is recommended to place the additional resistor on the side of the cable with the connected device instead of the side of the USC card to ensure the save state even in case of cable problems.
In addition to the function of generating a save state, pull-up resistors can also be used to reduce the rise time of Opto_Outs.