QidiAutoPA compatibility

QidiAutoPA is a fairly simple shim that aims to make autopa work on the Qidi Q2.

Performance

Even though the CS1237 can reach up to 1280Hz, Qidi doesn't expose any way to get real streamed data; therefore the most we can reach is about 100-120Hz because we have to use an alternative way. This is a bit low for autopa, but it works.

Now for quality: On my personal machine using Elegoo Rapid PLA+ at 230°C: autopa (2026/10/04) gave a PA of 0.028 on Sweep mode and 0.024 on Decay experimental mode.

This is the PA calibration test I ran right after:

Installing

I highly recommend logging in as 'qidi' (password: qiditech) and not 'mks', otherwise you will get file permission/ownership errors.

1. Install autopa as normal.

2. Assuming your klipper install is at your home:

git pull https://github.com/Unii93/QidiAutoPA.git
cd QidiAutoPA
cp load_cell.py ~/klipper/klippy/extras/load_cell.py
cp qidi_load_cell.cfg ~/printer_data/config/qidi_load_cell.cfg

3. In printer.cfg, above the #*# <---------------------- SAVE_CONFIG ----------------------> marker, add [include qidi_load_cell.cfg]

4. Then either power cycle your printer or run sudo systemctl restart klipper to fully restart klipper. Standard RESTART or FIRMWARE_RESTART won't work as they don't restart the klippy extras.

5. You're done.
   (head to http://IP/autopa if you installed autopa with the web interface)

6. Verify it works (optional) Run LOAD_CELL_DEBUG, if you see 'sensor: found' and a non zero 'raw now', it works.

Debug commands

If you don't plan on actively contributing to this project, you don't need these commands.

• LOAD_CELL_DEBUG: Debug read of the load cell (path, sample count, value range, actual sps)
• LOAD_CELL_TARE: Force Tare
• LOAD_CELL_PROBE_STREAM: Debug read of the load cell but stream

How it works

Qidi's CS1237 driver is a proprietary compiled Cython module, meaning everything done here is technically guess work.

The base functionement is to register a [load_cell] that autopa can use and bridge it to Qidi's driver.

• autopa's UI charts live force work with Moonraker's load_cell/dump_force websocket
  -> sent as {'data': [[time_s, grams, counts, tare], ...], 'errors': N}
• Qidi does not expose a way to obtain a bulk stream (or I couldn't make it work) even though the binaries show proof of plans for a bulk stream. Instead we have to spam one shot reads (the same thing Qidi's WEIGHTING_DEBUG_QUERY command does), this is the main reason why we are limited to around ~100 sps and not the 1280Hz the sensor could reach.

autopa needs	shim provides
lc.name	config section name
lc.sensor.get_samples_per_second()	configured rate
lc.get_collector()	collector object
.start_collecting(min_time=t0)	subscribes to probe_air's bulk stream, (re)tares
.collect_until(t_end)	pumps reactor, returns (rows, errors)
.is_started (settable)	autopa uses this to release the collector

rows are the 4-column [time_s, grams, counts, tare] records autopa expects; autopa computes force as -(counts - tare).