Input (open drain) - WaveNet

Use this configuration to switch an open-drain ouput. The open-drain output can be regulated by an external system. This allows you to connect an external system to the WaveNet. Note that the switching behaviour is inverted:

  • Open drain of the signal generator open/unswitched: Pull-up resistor "pulls" the digital input to +3.3 VDC (high level). An event is detected for this input.
  • Open drain of the sensor closed/switched: Input is short-circuited to ground (low-level).
  1. Connect the ground potentials of the signal transmitter and the router node.
  2. Connect the positive terminal of the power connection next to the IO connector to the open-drain output of the signal transmitter via the pull-up resistor X.
  3. In addition, connect the open drain output of the signal transmitter to one of the digital inputs DI1, DI2 or DI3.

The pull-up resistor depends on the open-drain output of the signal transmitter. A possible value is 1 kΩ.

IMPORTANT

Calculation of pull-up resistance

Pull-up resistors that are too small can damage the power connection next to the IO-Connector and overload the open-drain connection of the Signal Giver. Too large pull-up resistors make the signal unclean.

The pull-up resistor must be as small as possible and as large as necessary.

  1. Do not select a value lower than 16.5 Ω.
  2. Do not select unnecessarily large values.