From 37a117e64fe44b0ba4879e67491e1a54fef7c391 Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Sun, 28 Nov 2021 20:41:54 -0500 Subject: [PATCH] docs: Update TMC_Drivers.md with notes on spreadCycle vs stealthChop modes Signed-off-by: Kevin O'Connor --- docs/TMC_Drivers.md | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/docs/TMC_Drivers.md b/docs/TMC_Drivers.md index df9dae1f..2f456d4a 100644 --- a/docs/TMC_Drivers.md +++ b/docs/TMC_Drivers.md @@ -58,12 +58,25 @@ probing, probe calibration, and similar. The `driver_TPOWERDOWN` and `driver_IHOLDDELAY` should also be calibrated accordingly. If unsure, prefer to not specify a `hold_current`. -## Enabling "StealthChop" Mode +## Setting "spreadCycle" vs "stealthChop" Mode By default, Klipper places the TMC drivers in "spreadCycle" mode. If the driver supports "stealthChop" then it can be enabled by adding `stealthchop_threshold: 999999` to the TMC config section. +In general, spreadCycle mode provides greater torque and greater +positional accuracy than stealthChop mode. However, stealthChop mode +may produce significantly lower audible noise on some printers. + +Tests comparing modes have shown an increased "positional lag" of +around 75% of a full-step during constant velocity moves when using +stealthChop mode (for example, on a printer with 40mm +rotation_distance and 200 steps_per_rotation, position deviation of +constant speed moves increased by ~0.150mm). However, this "delay in +obtaining the requested position" may not manifest as a significant +print defect and one may prefer the quieter behavior of stealthChop +mode. + It is recommended to always use "spreadCycle" mode (by not specifying `stealthchop_threshold`) or to always use "stealthChop" mode (by setting `stealthchop_threshold` to 999999). Unfortunately, the drivers