myCNC-ET7 controller board

myCNC-ET7 controller specification

Number of motor outputs


Motor driver outputs

differential line driver outputs compatible with EIA RS-422 Standard

Maximum pulse frequency

3 MHz

Binary inputs

16x galvanic isolation,
PNP/NPN sensor compatible

Encoder inputs

3x incremental encoder inputs,
differential line driver (EIA RS422 compatible),
hardware decoded, 5MHz max frequency

Binary outputs

5x - pluggable relays 10A, NO/NC contacts
11x - open collector, 24V, 0.25A

PWM outputs

3x - open collector, 24V, 0.25A,

ADC inputs

2x - 0...10V range, differential inputs, fully galvanic isolated
(for plasma arc voltage measure, THC control),
6x - 0...3V range

DAC output

1x - 0...10V (for spindle speed control and relative applications)


1x RS422 full duplex serial communication
2x RS485 half-duplex serial communication

External operator panel connector

Up to 25 external keys

Custom panels (available on bulk orders of 10+ panels) can be customized to include up to 2 rotary encoders, up to 2 double-axes joysticks OR
up to 4 potentiometers (shared with 4x ADC inputs)

Power supply outputs for control computer

2x DC-DC converters 5V 1.5A

Please find the full ET7 control board connectors descriptions on our online documentation website

ET7 top view


Power supply connection

myCNC-ET7 control board uses 24VDC . The board contains 4 pins for connection +24V (joined internally) and a number of GND pins for convenient connection of external devices. Power Supply 24V DC and +24V and GND pins are shown on a picture below:


Pulse-Dir outputs

ET7 has 6 channel pulse/dir outputs, 3MHz max pulses frequency.

ET7 pulse dir outputs conform to the RS422 standard and are compatible with most of servo and stepper drivers (line driver with paraphase signals of positive and negative polarity). Internal schematic for pulse-dir is shown on a picture below.

The pulse/dir schematic is shown below: pulse-dir6.jpg


ET7 Output pins

ET7 board contains 19 output pins-

  • 5 relay outputs (OUT#11 … OUT#15)
  • 11 open collector outputs (OUT#0 … OUT#10)
  • 3 PWM outputs (PWM#1, PWM#2, PWM#3)
WARNING: ET7 board rev.1,2 has Output pin names printed on Bottom side of the board. 
These names are NOT correct and differ from actual output addresses. 
Please check the table below to find out the actual output address
SILK printActual Output Pin Address
P0A OUT11 (A)
P0B OUT11 (B)
P0C OUT11 (C)
P1A OUT12 (A)
P1B OUT12 (B)
P1C OUT12 (C)
P2A OUT13 (A)
P2B OUT13 (B)
P2C OUT13 (C)
P3A OUT14 (A)
P3B OUT14 (B)
P31 OUT14 (C)
P4A OUT15 (A)
P4B OUT15 (B)
P41 OUT15(C)

Schematic for ET7 inputs & outputs is shown below


Galvanic isolated inputs

ET7 control board has 16 galvanic isolated binary inputs, 4 groups of 4 inputs each. Each group has separate power supply pins so inputs can be powered from different power sources. Using PNP and NPN sensors simultaneously is possible too.

Galvanic isolated inputs schematic is shown below

Connectors pinout for binary inputs is shown on a picture


Encoder Inputs

ET7 control board has 3 AB incremental encoder inputs with hardware implemented decoding. Max pulse frequency of encoder pulses is 3MHz. 6 encoder input signals are mapped to General purpose binary input addresses 20…25 and can be used as normal binary inputs. Encoder inputs are line driver differential signal compatible.

Encoder inputs schematic is shown below

Encoder inputs connector pinout is shown on a picture


ADC Inputs

myCNC-ET7 controller has 8 ADC inputs.

  • 6 ADC inputs 0-5V range
  • 2 ADC inputs with galvanic isolation for save and convenient connection of Arc Voltage signal from Power station. Galvanic isolated ADC inputs are 0..10V, so High Voltage Arc signal CANNOT be connected directly to ADC inputs, voltage divider is NEEDED.

The 0-5 V ADC inputs schematic is shown below:

Isolated ADC inputs schematic is shown below:

Connectors pinout for ADC inputs is shown below


Non-isolated ADC inputs have a 0…5V Range. Connector with non-isolated ADC inputs also has the GND and +5V DC output pins for convenient potentiometer connection. Picture below shows an example for potentiometer connected to ADC2 input.


WARNING: The names for the ADC inputs printed at the bottom of the board are NOT correct. 
Please consult the above schematics for the ADC0/ADC1 input locations.

Jumpers J1, J2, J3 and J4

In order for the board connections to function without an external power supply, the connections can be wired as to draw power from the +24V power supply of the board itself. In order to simplify the setup required for this procedure, jumpers 1 through 4 are put in place, as shown in the diagram below: et7-jumper-connection-001.jpg

Each jumper corresponds to its respective IN group number (for example, J4 for Group 4). In this way, in a configuration without an external power supply, the correct jumper for the group can be closed to supply power from the internal +24V. The switch should also short the wire to GNC (0V) in order for the circuit to be closed.

WARNING: If an external power supply is used, respective jumpers for the group should be OPEN

RS422/RS485 Bus

The myCNC-ET7 control board has a RS422/RS485 bus connector. Modbus ASCII/RTU and Hypertherm Serial communication interfaces are implemented in the myCNC-ET7 control board.

RS485 bus is enabled by default.

To enable RS422 interface you need to

  • close jumper J(#)
  • setup RS422 interface in the control software.

Please contact our support team if you need to use a RS422 bus.

A RS422/RS485 schematic is shown below

RS422 connector pinout shown below. NOTE: While all of the RX/TX ports (RX A, RX B, TX A, TX B) are used for the RS422 connection (such as a Hypertherm machine), only RX A and RX B are utilized in an RS485 configuration.


DAC output

The myCNC-ET7 control board has a DAC output for spindle speed control. DAC output range is 1..12V Actual Max DAC voltage (ie 10V, 5V, 6V) can be set up in the myCNC control software.

Connection Examples


Stepper driver connection (4 axes)


3-wire NPN sensor connection example (external power supply)

Jumpers J1,J2,J3,J4 are all open.

3-wire PNP sensor connection example (external power supply)

Jumpers J1,J2,J3,J4 are all open.

3-wire NPN sensor connection example (internal power supply)

Internal power supply.
One of jumpers J1,J2,J3,J4 (J4 in case of this example) is closed.

3-wire PNP sensor connection example (internal power supply)

Internal power supply.
All of jumpers J1,J2,J3,J4 are open.

As the sensor requires a 24V power supply, it is necessary to connect it to the 24V port, not the 5V.

Switch connection example (internal power supply)

Jumper for selected group (one of J1,J2,J3,J4) is closed.

Common wire for 4 optocouple units is connected to internal +24V if Jumper is closed. Switch should short another optocouple input to GND (0V) to activate input pin.

J(#) - in this case, J4 - should be closed to connect optocouple pin to +24V. Switch should also short the wire to GNC(0V).

Switch connection example (external power supply)

Jumpers J1, J2, J3, J4 are all open

Spindle Speed control over DAC (0-10V) output


Board dimension

ET7 keypad board

We have a simple keypad board that can be used with the ET7 controller. Keypad board is connected to an ET7 controller through a `20 wires flat cable. Keypad contains 23 keys, 2x rotary encoders and double-axes simple resistive joystick.

ET7 control board interface to connect external keyboard is shown below

ET7 connector pinout


ET7 connector X4 pinout table

X4 connector to External 25-keys keyboard  
Pin# Name Comments
1 OUT A Keyboard matrix output pins
2 OUT B Keyboard matrix output pins
3 OUT C Keyboard matrix output pins
4 OUT D Keyboard matrix output pins
5 OUT E Keyboard matrix output pins
6 IN #1 Keyboard matrix input pins
7 IN #2 Keyboard matrix input pins
8 IN #3 Keyboard matrix input pins
9 IN #4 Keyboard matrix input pins
10 IN #5 Keyboard matrix input pins
11 E#0 Encoder input (General purpose input)
12 E#1 Encoder input (General purpose input)
13 E#2 Encoder input (General purpose input)
14 E#3 Encoder input (General purpose input)
15 ADC _  
16 ADC _  
17 ADC _  
18 ADC _  
19 GND  
20 5V  



Each key, rotary encoder and the joystick functions can be programmed in configuration dialogs.

Schematics of the external ET7-KEY board is shown below

Control computer for myCNC-ET7

myCNC-ET7 board works under control of myCNC software. Control computer needs to build a complete CNC control system based on myCNC. It can either be a standard desktop/industrial computer with Linux or MS Windows OS installed
a small single board computer like the Odroid-C2, Odroid-XU4, or a Raspberry-Pi3/Pi2


myCNC-ET7 board contains a built-in DC-DC converter and mounting holes to install and power-up the Odroid/Raspberry computer board.

ET7 with Odroid-C2 computer mounted

A standard monitor with an HDMI port can be connected to the Odroid-C2 computer board. Screen resolution up to 1920x1080 (Full HD) is supported.  Fully functional Ubuntu 16.04 Linux and myCNC control software can be installed on the computer. NC code files can be uploaded to the computer through Wifi (Samba Server, FTP Server installed on the computer) or USB disks.

We can offer affordable 10"/15.6" screens with resistive touch to build a complete stand-alone CNC control kit.





See also: