README: Add PID Output Clamping section

Explains the need of having separate "max_i_pos/output_max" and
"max_i_neg/output_min" values; They serve different purposes.

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                        |

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)