flake: Introduce PyThermostat scripts to devShell

Make executable Python scripts in the PyThermostat root available in the
development shell (e.g. thermostat_plot, thermostat_autotune,
thermostat_test).

README.md

@@ -239,6 +239,22 @@ of channel 0 to the PID algorithm:
 output 0 pid
 ```
 
+### PID output clamping
+
+It is possible to clamp the PID algorithm output independently of channel output limits. This is desirable when e.g. there is a need to keep the current value above a certain threshold in closed-loop mode.
+
+Note that the actual output will still ultimately be limited by the `max_i_pos` and `max_i_neg` values.
+
+Set PID maximum output of channel 0 to 1.5 A.
+```
+pid 0 output_max 1.5
+```
+
+Set PID minimum output of channel 0 to 0.1 A.
+```
+pid 0 output_min 0.1
+```
+
 ## LED indicators
 
 | Name | Color | Meaning                        |

flake.nix

@@ -63,12 +63,24 @@
         version = "0.0.0";
         src = "${self}/pythermostat";
 
-        propagatedBuildInputs =
-          with pkgs.python3Packages; [
+        propagatedBuildInputs = with pkgs.python3Packages; [
           numpy
           matplotlib
         ];
       };
+
+      pythermostat-dev-wrappers = pkgs.runCommandNoCC "pythermostat-dev-wrappers" { } ''
+        mkdir -p $out/bin
+        for program in ${self}/pythermostat/*.py; do
+          if [ -x $program ]; then
+            progname=`basename -s .py $program`
+            outname=$out/bin/thermostat_$progname
+            echo "#!${pkgs.bash}/bin/bash" >> $outname
+            echo "exec python -m $progname \"\$@\"" >> $outname
+            chmod 755 $outname
+          fi
+        done
+      '';
     in
     {
       packages.x86_64-linux = {
@@ -90,11 +102,15 @@
             openocd
             dfu-util
             rlwrap
+            pythermostat-dev-wrappers
           ]
           ++ (with python3Packages; [
             numpy
             matplotlib
           ]);
+        shellHook = ''
+          export PYTHONPATH=`git rev-parse --show-toplevel`/pythermostat:$PYTHONPATH
+        '';
       };
 
       formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt-rfc-style;

pythermostat/autotune.py

@@ -1,5 +1,6 @@
 import math
 import logging
+import time
 from collections import deque, namedtuple
 from enum import Enum
 
@@ -236,13 +237,14 @@ def main():
 
     tec = Client()
 
-    data = next(tec.report_mode())
+    data = tec.get_report()
     ch = data[channel]
 
     tuner = PIDAutotune(target_temperature, output_step,
                         lookback, noiseband, ch['interval'])
 
-    for data in tec.report_mode():
+    while True:
+        data = tec.get_report()
 
         ch = data[channel]
 
@@ -255,6 +257,8 @@ def main():
 
         tec.set_param("output", channel, "i_set", tuner_out)
 
+        time.sleep(0.05)
+
     tec.set_param("output", channel, "i_set", 0)