From c6d6755f7fe0caa9542dbc6b77e3f65f2328bd34 Mon Sep 17 00:00:00 2001
From: sandst_a <anders.sandstroem@psi.ch>
Date: Fri, 6 Dec 2024 17:05:54 +0100
Subject: [PATCH] Update readme.md

---
 readme.md | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/readme.md b/readme.md
index d6860bf..4400ce7 100644
--- a/readme.md
+++ b/readme.md
@@ -69,6 +69,21 @@ Cannot move faster than 1720
 * +1.35 deg ttd_28
 * +1.8  deg ttd_29
 
+### Hich accuracy tests (Ulrich Wagners test setup)
+0.5mm pitch and 32bit 1nm resolution Renishaw
+Requirement within +-200nm
+Attocube interferometer as reference
+
+Closed loop:
+
+Too low resolution in output (velocity setpoint). Basically a 1 or -1 as velo setpoint is too big.
+
+Open loop:
+
+Running in open loop made the situation much better but resulted in an offset. Motor record retries would be needed to make this work.
+
+Impact of run current and stdby current is unclear...
+
 ## ipos4808
 ```
 ${SCRIPTEXEC} ${ecmccomp_DIR}applyComponent.cmd "COMP=Motor-Generic-2Phase-Stepper,  MACROS='I_MAX_MA=1000,I_STDBY_MA=200,I_CTRL_GAIN=1.0,I_CTRL_INT=0.26'"
@@ -88,6 +103,17 @@ ${SCRIPTEXEC} ${ecmccomp_DIR}applyComponent.cmd "COMP=Motor-Generic-2Phase-Stepp
 * +1.35 deg ttd_6
 * +1.8  deg ttd7
 
+### Hich accuracy tests (Ulrich Wagners test setup)
+0.5mm pitch and 32bit 1nm resolution Renishaw
+Requirement within +-200nm
+Attocube interferometer as reference
+
+Closed loop:
+Issue when going to stdby current, then axis move and current is applied again and again..
+
+Open loop:
+Running in open loop made the situation much better but resulted also here in an offset. Motor record retries would be needed to make this work.
+
 ## EL7047
 ```
 ${SCRIPTEXEC} ${ecmccomp_DIR}applyComponent.cmd "COMP=Motor-Generic-2Phase-Stepper, MACROS='I_MAX_MA=1000, I_STDBY_MA=200, U_NOM_MV=48000,R_COIL_MOHM=8000,L_COIL_UH=9700 ,SPEED_RANGE=2'"
@@ -194,6 +220,16 @@ Works roughly up to 3000deg/s but osc
 * +1.35 deg ttd_34
 * +1.8  deg ttd_35
 
+### Hich accuracy tests (Ulrich Wagners test setup)
+0.5mm pitch and 32bit 1nm resolution Renishaw
+Requirement within +-200nm
+Attocube interferometer as reference
+
+Closed loop:
+Issues to enable.. Issuses with encoder. needed to match the single turn bits as giood as possible in cfg (19bits approx 500000)
+The actual position that the drive sends is scaled based on this so it's useless..
+
+Got it working fro a short time but then it was rather noise and similar isses when going to stdby current..
 
 # Conclusions
 
@@ -201,3 +237,5 @@ Works roughly up to 3000deg/s but osc
 * Current noise is significantly reduced with lower motor supply voltage (only tested with EL7047)
 *... much more..
 
+For the high accuracy issues I think it aslo can be related to to low friction of Ulrichs stage. Seems easier to position the test owis stages (howvere lower accuracy encoder).
+