Digital Inputs

The digital inputs of Radonix control boards are labeled as I[nn], where nn represents a number greater than zero and indicates the input number. These inputs are opto-isolated and have low noise sensitivity due to their relatively low impedance—approximately 3 kilo-ohms.

In 4-axis and 6-axis control boards, a switch is available for every eight inputs to toggle between NPN and PNP modes. When using devices or sensors with PNP outputs, the switch must be set to the PNP position. Conversely, when using devices or sensors with NPN outputs, the switch must be set to the NPN position.

The internal circuit schematics for the inputs in NPN and PNP modes are shown in Figures 5 and 6, respectively.

The settings that store information about the inputs can be found under the following branch in the configuration tree:

Setting: System / InPort[nn]

Each input contains three variables: Enabled, Link, and NC.

• Enabled is used to activate or deactivate the input.
• Link is used to associate the input with a specific pin or function.
• NC is used to define whether the input is normally closed or normally open.

Router devices typically use the connections listed in Table 2 to define inputs.

Table 2 – List of Connections for Inputs

According to standards, normally closed (NC) switches are often used for safety purposes. Therefore, it is recommended to use normally closed (NC) switches for Limit and Emergency functions as well. In such cases, the corresponding input variable should be set as:

NC=True

In various branches of industrial automation, PNP and NPN terms have their equivalents. A few examples include:

• NPN = Sink = Low Active
• PNP = Source = High Active

In industry, NPN switches and sensors are generally more common.

If automatic tool changing is used on the router device, feedback from the spindle is connected to the inputs of the control board. These feedback signals are typically PNP, so they should be connected to a group of inputs configured in PNP mode.

The wiring diagrams for connecting inputs to mechanical switches and proximity switches in both PNP and NPN modes are shown in Figures 7 and 8.