Inputs

The HOME inputs are required for the machine to be able to detect the ‘home’ position.

The home input can be configured into two modes, each mode describes what type of switch or sensor is connected. If the switch or sensor is activated, it means that it will switch either to ground (NPN) or to 24V (PNP).

PNP = Input should be ‘HIGH’ (24V) to detect the switch/sensor being activated. NPN = Input should be ‘LOW’ (0V) to detect the switch/sensor being activated.

This mode selection is done by setting 4 jumpers

The image below shows how the input operates.

When in NPN mode the input needs to switch to ground to be activated.

When in PNP mode the inputs need to switch to +24V to be activated.

As described above, our hardware supports NPN and PNP. There is one more important condition, using Normally Open (NO) or Normally Closed (NC) sensors. This NO or NC indicates whether the output is active (NC) or non-active (NO) when the sensor is not activated.

The NC sensor has an extra benefit; if, for any reason, the cable to the sensor is cut, it will automatically report the sensor's activation since this would indicate that the sensor is activated. If a NO sensor is used, the machine will try to home without ever detecting that sensor, potentially causing damage to the machine.

Of course, our software needs to know what the input is supposed to be when it is not activated. Therefore, this can be configured. In our software, a button will configure the home inputs to the correct settings based on their value when the sensor is not activated, preventing you from having to think about what it is supposed to be.





The DRVALM can be used to report problems with the motor driver. Since there is only a single input, the motor driver's outputs can normally be combined with this input.

The input can have two modes, either NPN or PNP. This means either it will react when this input is switched to ground (NPN), or the input signal goes to 24V (PNP).

This mode can be set via a jumper

All alarm outputs of the motor driver need to be wired together. If the alarm outputs of the drives are open-collector outputs, so that the alarm outputs of all drives can be coupled together, and each output can pull the alarm input low to generate an alarm. The input of the DRVALM input can be set to NPN.

Please note, check that the motor driver ALARM output is truly configured to be ‘open’ if not active.

The image below shows such a setup.

Each drive can generate an alarm that will switch low the DRVALM input, resulting in detection of this alarm.

The RUN and PAUSE inputs can be used to externally start or stop a job. However, they are also used when you want to connect a wired external pendant. If the software is in JOGWHEEL modus these inputs are used for zeroing the position (START) or selecting the axis (PAUSE).

Using the PAUSE or RUN input is simply connecting a push button to it, with one side connected to GROUND and the other to the input of the board.

The HW-A/HW-B inputs can be used to connect a handwheel for exactly setting the position of an axis or changing the 'feedrate'. The position of the axis can only be changed if the software is in JOGWHEEL modus.

The image below shows how a pendant can be connected to these inputs.



The analog inputs can have several functions

For this application the 3.3V (AVDD) is made available on pin #10 of connector CN2. Do not use this voltage for other applications!

If you want to test this input, a simple 10k potentiometer can be used as shown in the image below.

Using this potentiometer to control the feedrate can be changed in the application setup it should be indicated that an analogue input is used. In this case either ‘Analog 1’ or ‘Analog 2’.

The EXT-ERROR input can be used for indicating any external ERROR has occurred. The behaviour of this input can be indicated in the setup of the application.

The input can have two modes, either NPN or PNP. This means either it will react when this input is switched to ground (NPN), or the input signal goes to the 24V (PNP).

This mode can be set via jumper JP13



The E-STOP input is used for indicating an EMERGENCY. The CNC720 is equipped with hardware features that can shut down the outputs if an E-STOP occurs, this is in addition to the software behaviour in case of an E-STOP condition.

The hardware E-STOP functionality shuts down the following outputs:

The board features a connector (CN3) to which the E-STOP switch needs to be connected.

The software behaviour of the E-STOP can be defined in the software setup. The hardware behaviour of the E-STOP is through several jumpers.

The E-STOP inputs need to be connected with a ‘normally closed’ (NC) switch. As a result, if the E-STOP cable has a broken wire this will automatically trigger an E-STOP condition.

The figure below shows a basic schematic of how this works

The SPINDLE-X input can be used to connect an external sensor that indicates the rotation of the spindle or used in case of tapping when used in a lathe application.

The SPINDLE-X has a maximum input level of 5V and will be damaged if 24V is applied.

To use the SPINDLE-X the input signal needs to switch to ground to be active. The image below shows this.

The probe input has a dual use. It can be used for the tool measurement, measuring the height of a tool, or it can be used for probing an object. If both tools are used, they can be connected together to this input. However, make sure that they both use the same kind of output signal.

The input can have two modes, either NPN or PNP. This means either it will react when this input is switched to ground (NPN), or the input signal goes to 24V (PNP).

This mode can be set via a jumper.