Digital Inputs

Digital Inputs Overview

Radonix control boards’ digital inputs are labeled I[nn], where nn is a positive integer indicating the input number. These inputs are opto-isolated (≈3 kΩ impedance) for low-noise operation.

Figures 5 & 6 show the internal wiring for NPN (sink/low-active) and PNP (source/high-active) modes, respectively:

Figure 5 – NPN vs. PNP input wiring

Configuration lives under:
Setting → System → InPort[nn]

Each input has three settings:

• Enabled: enable/disable the input
• Link: assign to a pin or function
• NC: True = normally-closed, False = normally-open

Common Link Options

Function	Type	Link syntax
Home sensor	Pin	HomePin,[Axis]
Positive limit sensor	Pin	LimitPin,[Axis]
Negative limit sensor	Pin	LimitPin,[-Axis]
Surface-detect sensor	—	SurfaceDetectorPin
Trigger surface detect (e.g. Z axis)	—	SurfaceDetector,Z
Emergency stop	Function	Emergency

Table 2 – Input link options

Best practice: use normally-closed (NC) switches for safety (NC=True).

Industry terms:

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

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Wiring Examples

Figure 7 – NPN (sink) wiring

Figure 8 – PNP (source) wiring