CNC Machine Information
| Specification | Value |
|---|---|
| Manufacturer | Isel |
| Model | GFM4433 |
| Number of axes | 3 |
| Spindle controller | Huanyang HY02D223B |
| Specification | Value |
|---|---|
| Model | Nanotec 4T5618M3300-A |
| Max Current | 3A |
| Degrees per step | 1.8 |
The original controller in the CNC machine was an ISEL IMC4. This controller required the use of a specific (and old) version of Galaad in order to control the machine.
Somebody on a forum reverse engineered the control board, which has provided a very useful schematic that has aided the refitting of the machine.
The stepper motors and end stop switches for each axis are connected to the main board via a cable with a DB-9 connector. The pinouts were derived from the above schematic. Note: This still needs to be tested, so is not guaranteed to be 100% correct.
| Pin number | Connection |
|---|---|
| 1 | Motor Phase A+ |
| 2 | Motor Phase A- |
| 3 | Motor Phase B+ |
| 4 | Motor Phase B- |
| 5 | ? |
| 6 | N/C |
| 7 | Limit Switch |
| 8 | N/C |
| 9 | Limit Switch |
There are seven buttons and switches on the front panel of the machine.
| Position | Type | Function |
|---|---|---|
| Far Left Upper | Push Button, Green | Start cycle |
| Left Upper | Push Button, Red | Stop Cycle |
| Far Left Lower | Push Button, White Illum. | Cover Latch |
| Far Right Upper | Mushroom E-Stop Button | Emergency Stop |
| Right Upper | Push Button, Green (Illum.) | Power On |
| Far Right Lower | DPST Rocker, Red (Illum.?) | Main Power Switch |
| Right Lower | Key Switch | "Test/Run" |
The push buttons are not clearly marked, but appear to be EAO Series 31, or equivalent, with 5A/240V rated NC and NO contact pairs. They require a special castellated spanner for their mounting nuts. All these button can be fitted with midget groove 1.2W indicator bulbs.
The E-stop button contact block is a Schlegel AT2, with 2NC+2NO contacts.
The key switch contact block is a TH Contact 593561-020 for TH25 switches. There does not appear to be a key for this switch.
The door interlock is a SCHMERSAL AZM 170-02zk-2321.
The new CNC controller consists of the following hardware:
- An MKS DLC32 ESP32-based controller board running the FluidNC firmware
- A 600W 36V switching power supply
- 3 x DM556 (clone) stepper driver modules
- A TTL to RS485 module for driving the spindle controller
On the ESP32 module, pins 17-22 are not connected. These pins are part of a group that appears to be for a quad channel SD card interface. Two of these, pins 17 and 18, had been assigned for serial comms to the VFD via RS485, but FluidNC reported the error 'Unusable gpio'. Presumably the whole group is unusable, hence they are not connected, while stepper signals that could have been assigned to them are output using I2SO and shift registers.
To provide some an RS485 link and extra GPIO for buttons, interlocks and coolant valves, etc. the control board's EXP1 and EXP2 connectors will be utilised. These ports are intended for use with LCD displays with SPI interfaces. Some of the the GPIO pins are buffered and can only be used as outputs. GPIO pins
| EXP1 Pin | GPIO pin | Assigned function |
|---|---|---|
| 1 | I2SO.7* | Aux Output 4 |
| 3 | GPIO.5* | Aux Output 3 |
| 5 | GPIO.26* | Aux Output 2 |
| 7 | GPIO.25* | Aux Output 1 |
| 9 | 0V | GND |
| 2 | n/c | n/c |
| 4 | GPIO.27* | RS485 Dir |
| 6 | GPIO.4** | RS485 Txd |
| 8 | GPIO.33 | RS485 Rxd |
| 10 | +5V | +5V |
- Output only **Patch to GPIO.4 (SCL) on the MKS.
I2SO.7 (BEEPER) and GPIO.32 (LC/Spindle) also have open collector outputs with 12/24v on the MKS board for outputs that do not require isolating relays. The LC/Spindle output can handle high current and inductive loads. Eg. a 24v pneumatic valve coil could be operated directly by this outputs.
| EXP2 Pin | GPIO pin | Assigned function |
|---|---|---|
| 1 | GPIO.19 | Aux Input 3 |
| 2 | GPIO.18 | Aux Input 2 |
| 3 | n/c | n/c |
| 4 | GPIO.0* | Aux Input 4 |
| 5 | GPIO.32* | Aux Input 5 |
| 6 | GPIO.23 | Aux Input 1 |
| 7 | n/c | n/c |
| 8 | RESET | None |
| 9 | 0V | GND |
| 10 | +3.3V | +3.3V |
*If required, patch to GPIO.0 (SDA) or GPIO.32 (SCL) (if not required for output) on the MKS. GPIO.0 is also the boot mode pin, and a button on this pin would allow for entering into flash mode.