Warning
- Make sure to read this guide in its entirety before using PZ Probe.
- This product is rated to a maximum of 5V. Exceeding this voltage can lead to serious complications!
- This product is not plug and play.
- Damage to the printing bed is not included under warranty.
- Maximum ambient printing temperature: 75°C
- Check the back of the board for the batch number prior to installation to ensure you are setting up correctly.
Features
- Impact trigger that simulates a switch and can replace Voron Tap and other Z-Probes.
- LED indicators
- Press button to select configurable presets
- IIR filter to increase noise immunity and noise rejection
- Support both UART and I2C communication protocol
- Voltage range of 3.3V-5V
- Reversed voltage protection
- Safety trigger during communications
The table below displays the minimum force (N) required to trigger the PZ Probe for the highlighted speeds.
| Preset | Threshold (Sensitivity) | Filter (Fc=260, F_BW=50) | 300 mm/min | 500 mm/min | 700 mm/min | 900 mm/min | 12000 mm/min |
|---|---|---|---|---|---|---|---|
| 0 | 5 | Off | 0.005 | FT | FT | FT | FT |
| 1 | 10 | Off | 0.005 | 0.005 | 0.015 | 0.020 | 0.130 |
| 2 | 15 | Off | 0.005 | 0.005 | 0.015 | 0.025 | 0.140 |
| 3 | 1 | Off | FT | FT | FT | FT | FT |
| 4 | 5 | On | 0.050 | 0.050 | 0.100 | 0.105 | 0.150 |
| 5 | 10 | On | 0.050 | 0.080 | 0.115 | 0.140 | 0.225 |
| 6 | 15 | On | NT | 0.080 | 0.115 | 0.110 | 0.280 |
| 7 | 1 | On | 0.010 | 0.045 | 0.090 | 0.100 | 0.145 |
FT = False Triggering
NT= Not Triggering
Setup Guide
General Notes
After sucessfully connecting and mounting the PZ Probe, as well as adding the code needed in the configuration, there are some important details about how the PZ Probe works and what impacts the performance:
- The more rigid the motion system that the PZ Probe is installed on, the better it will perform. This means, lower sensitivity and probing speeds can be used. Less rigid systems are more likely to not trigger and therefore usually require higher probing speeds.
- Vibrations from the motor and Z-axis moving is the most common cause for false triggering and so it is important to drop the motor current during probing as much as possible. This will also save damaging your bed if no triggering occurs.
- A useful way to test the PZ Probe while changing settings is to lightly tap the tip of the nozzle with a small metal ruler or pen. A yellow light will appear on the PZ Probe Board if a trigger is outputted. If you don't observe this behaviour, please check the troubleshooting guide.
- It is recommended when probing the bed, to probe when the nozzle temperature 50°C below the target temperature to avoid oozing. Plastic on the nozzle flat will result in poor probing repeatability and potentially result in a No Triggering failure mode.
- Probing speed is very important. Probing too slow will result in a No Triggering failure mode. Probing too quickly will result in inconsistent and inaccurate probing. See the troubleshooting section for more details. Acclerations and Jerk also has an impact on probing.
- The output signal (Trigger) from the PZ Probe board is an active low signal. This means that when idle it is high (5V/3.3V) and then triggered, the output signal does to 0V (GND).
Connecting PZ Probe to your printer
The Heatsink is mounted as with a normal Voron Heatsink.
The heatsink has a "wire" with a 4 pin connector coming out of the central body, this will be referred as the flat flex.
The flat flex can then be routed through the cable channel and then connected to the PZ Probe Board.
Connect the flat flex to PZ Probe Board as in the image below. Ensure the black stiffener is facing up as in the image.
- The EndStop connector - if you have an octopus board for example, this can plug straight into the endstop connector on the board.
- UART connector - if you have a Raspberry Pi, this can be connected directly to the pin header of the Pi.
See the tab "Configuration" > "Raspberry Pi with a Python script".
This is an optional connector to plug in, and is only needed when configuring the preset settings. - UPDI Connector - This can be used to program the microcontroller using a UPDI programmer. In most cases, users will not use this connector.
- I2C Connector - This can be used to configure the Preset settings with an alternative form of communication. This is the least preferred way of communication (UART is the recommended way).
PZ Probe Board Mounting
The PZ Probe Board can be mounted in 2 different ways:
- It can be mounted using the mounting holes by securing it with the M2 machine screws provided, in a convenient location on the printer or setup. Since the area around the mounting holes is clear, they can also be drilled to accommodate M3 screws.
If you are mounting the PZ Probe Board to Voron, you can mount the baord on the X-carriage, using the modified 3D-printed parts:
Printables: X-Carriage Printed Parts
- Attach double-sided tape (not provided) to the back of the PZ Probe Board, then place it in a convenient location on your printer or setup.You can break off the PCB's part with the M2 mounting holes by breaking the mouse bites - this is particularly useful for placing the PCB in a small area.
Firmware - Klipper
Before you start using PZ Probe, make sure to do the following changes to avoid any damage to your setup:
- These settings have been tested on our setup, but they may vary slightly depending on your setup. Please use them as a starting point, and make sure to go through all the steps below. Klipper Config
- During probing, reduce the current as much as possible without causing a stall. A good starting point is 40%, but lowering it further, if possible, will reduce the risk of damaging your bed. We have set our probing speed to 5 mm/s.
- In our testing procedures, we used the Roto toolboard (pin: !roto_tb). Make sure to correctly name it, as well as the other pins, according to your setup.
- Probe and check. If you experience false or no triggering, follow the steps in the troubleshooting tab.
Firmware - Duet
In Config.g add the following: Config.g
This is for Duet 3.6.0 onwards-Note that for G31, X and Y offset may need to be changed for your hotend. Z should be kept at 0.
You can now send commands via the command line as follows:
To write: M260.2 P1 S"STATUS\n"
Replace STATUS with any commands from the "Commands" section. \n is required at the end of the command.
To read: M261.2 P1 B10
The read command is rather limited as only a set number of bytes (B) can be read at anytime. So the command will need to be repeated several times and the B value may have to be changed to read the whole data packet received. All the values are returned in Hex, so these will need to be converted to ASCII to read the data externally outside of Duet. However, this provides a method of setting and reading the PZ-Probe controller with no additional hardware.
Peizo Washer Mounting
- 1Nm of torque applied to a screw going through the PZ-Probe Washer to preload the Piezo sensor. Ensure the screw has thread locker once you have it up and running (note that it can cause embrittlement in ABS) – as the screw coming loose over time will result in inconsistent probing. The actual torque value can be different, keeping the torque consistent is key.
- PZ-Probe Washer should be placed between two hard, smooth surfaces, covering all the washer to provide more reliable triggering.
- If the washer is going between two surfaces with a mounting screw – ensure most of the load goes through this screw. Having multiple screws will result in reduced sensitivity. It’s vital to have the Piezo element protruding from the mating surface to ensure the actuation is applied to the Piezo element and not the mating surface.
- An Example of using PZ-Probe Washer, between Revo Roto and the carriage of a Voron Trident:
- There is a brass washer between the Pz-Probe Washer and the Roto. This provides a hard, flat surface against all the Piezo element to ensure as much of the force as possible is transferred across the whole Piezo sensor.
- It can be beneficial to have a brass washer in between the carriage mount and the PZ-Probe Washer depending on the surface finish of the carriage.
- The PZ-Probe washer must be protruding from the plastic face of the carriage to ensure that the Roto extruder actuates the Piezo element and not the plastic face of the carriage.
