servotune: free parameter and scope tool for Lichuan A5 (LC10P) and B2 drives, testers wanted
Hi all,
Lichuan's PC software for the A5/LC10P and B2 is a parameter editor and not much more. I wanted something closer to the tuning tools other drive makers ship, so I've started writing one. It's called servotune. It's free (GPL), and runs on Linux and Windows.
It talks to the drive through its RS-485 Modbus port (CN3/CN4 on the A5, CN2 on the B2) using an ordinary USB-RS485 adapter. It doesn't need LinuxCNC and doesn't touch the step/dir side. The drive can stay wired to your Mesa card while you watch it and LinuxCNC moves the axis.
What the first release does:
- Scan and probe: finds the drive at any baud rate and format. A strictly read-only probe writes a report of which registers answer and how fast.
- Parameters: every parameter by group, showing the drive's value, the default, the range, and when a change takes effect (immediately, at stop, or after a power cycle). You can edit one, or load an .lcd file from Lichuan's software and write only the differences after a review screen. It can also save the drive to an .lcd file.
- Program a drive from a file: writes only what differs, reads everything back to verify it, and saves a report. The original values are journalled to disk first, so an interrupted session can be restored.
- Scope: the drive's own position following error, speed against speed command, and torque, live. It has triggers, cursors, captures you can overlay to compare before and after a gain change, and CSV export. This is useful with step/dir, where LinuxCNC never sees the following error but the drive does.
One thing to watch if you script this yourself: .lcd files trim trailing zeros, so "P08-00=30" on a 0.1 Hz parameter means 30.0 Hz (raw register 300). servotune takes the scaling from the manual, not from the file.
The honest bits:
- So far it has only been tested against its built-in simulated drive, not on a real drive. That's why it's tagged as a pre-release.
- The scope polls over Modbus. Lichuan doesn't expose an internal capture buffer, so expect roughly 30-180 samples a second depending on baud rate. That's enough for following error through a move, overshoot and settling time. It isn't enough to see fast oscillation, and the scope warns you when that might be happening.
- It doesn't drive test moves or offer guided tuning yet. That's next.
- The Windows build hasn't been run on Windows yet.
- The EtherCAT LC10E isn't supported.
How you can help:
If you have an A5/LC10P or a B2, please run the read-only probe and post the report, here or as a GitHub issue. It only sends Modbus read requests.
Each report answers something the manuals leave unclear: B2 register numbering, whether the A5 really runs at 115200 baud, and which monitor registers are 32-bit.
Downloads (Windows zip and Linux AppImage), source and docs available from my GitHub, linked under my profile.
Not affiliated with Lichuan, just a user for many
Hugh
