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P a g e
Connect dry contacts (pushbuttons, standard or momentary switches, relay
contacts, etc.) or open collector transistor outputs across the appropriate input
terminals and the input common terminal.
WARNING! Avoid supplying external voltage to these terminals!
All input ports are optically isolated to protect the module against unwanted effects
of ground loops, overvoltage or misconnections.
It should be noted that the galvanic isolation is only effective when an independent
power supply is used for powering the inputs. See section “Power Requirements”
if you don’t want to use two separate power supply units.
To assure an additional level of safe and reliable operation, the inputs are also
software protected against the effects of noise spikes that usually occur when
heavy inductive loads (motors, fans, etc.) are switched nearby. In most systems
lacking this level of protection, these spikes may result in unwanted operation.
Three-way switches can be implemented by simply connecting multiple
momentary switches in parallel.
Status LED Indicators
In order to make installation and debugging easier, communication and channel
status are displayed via LEDs.
Use the board layout drawing in Figure 4. to locate the status LEDs.
