frappy_psi.picontrol: software control loop

example usage: use a temperature controller without changing
the calibration setting:
reading the raw sensor, calibrate by software and use 'manual'
heater output

Change-Id: I3dbcf37e7726b48a0516d7aa30758be52b80fe58
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/33910
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

frappy_psi/picontrol.py

@@ -0,0 +1,86 @@
+# *****************************************************************************
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+#   Markus Zolliker <markus.zolliker@psi.ch>
+#   Jael Celia Lorenzana <jael-celia.lorenzana@psi.ch>
+#
+# *****************************************************************************
+
+"""soft PI control"""
+
+import time
+import math
+from frappy.core import Writable, Parameter, FloatRange, IDLE
+from frappy.lib import clamp
+from frappy.datatypes import LimitsType, EnumType
+from frappy.mixins import HasOutputModule
+
+
+class PImixin(HasOutputModule, Writable):
+    p = Parameter('proportional term', FloatRange(0), readonly=False)
+    i = Parameter('integral term', FloatRange(0), readonly=False)
+    output_range = Parameter('min output',
+                             LimitsType(FloatRange()), default=(0, 0), readonly=False)
+    output_func = Parameter('output function',
+                            EnumType(lin=0, square=1), readonly=False, default=0)
+    value = Parameter(unit='K')
+    _lastdiff = None
+    _lasttime = 0
+    _clamp_limits = None
+
+    def doPoll(self):
+        super().doPoll()
+        if self._clamp_limits is None:
+            out = self.output_module
+            if hasattr(out, 'max_target'):
+                if hasattr(self, 'min_target'):
+                    self._clamp_limits = lambda v, o=out: clamp(v, o.read_min_target(), o.read_max_target())
+                else:
+                    self._clamp_limits = lambda v, o=out: clamp(v, 0, o.read_max_target())
+            elif hasattr(out, 'limit'):  # mercury.HeaterOutput
+                self._clamp_limits = lambda v, o=out: clamp(v, 0, o.read_limit())
+            else:
+                self._clamp_limits = lambda v: v
+            if self.output_range == (0.0, 0.0):
+                self.output_range = (0, self._clamp_limits(float('inf')))
+        if not self.control_active:
+            return
+        self.status = IDLE, 'controlling'
+        now = time.time()
+        deltat = clamp(0, now-self._lasttime, 10)
+        self._lasttime = now
+        diff = self.target - self.value
+        if self._lastdiff is None:
+            self._lastdiff = diff
+        deltadiff = diff - self._lastdiff
+        self._lastdiff = diff
+        out = self.output_module
+        output = out.target
+        if self.output_func == 'square':
+            output = math.sqrt(max(0, output))
+        output += self.p * deltadiff + self.i * deltat * diff
+        if self.output_func == 'square':
+            output = output ** 2
+        output = self._clamp_limits(output)
+        out.update_target(self.name, clamp(output, *self.output_range))
+
+    def write_control_active(self, value):
+        if not value:
+            self.output_module.write_target(0)
+
+    def write_target(self, _):
+        if not self.control_active:
+            self.activate_control()

frappy_psi/softcal.py

@@ -28,6 +28,8 @@ from scipy.interpolate import splev, splrep  # pylint: disable=import-error
 
 from frappy.core import Attached, BoolType, Parameter, Readable, StringType, \
     FloatRange, nopoll
+from frappy_psi.convergence import HasConvergence
+from frappy_psi.picontrol import PImixin
 
 
 def linear(x):
@@ -232,3 +234,7 @@ class Sensor(Readable):
     @nopoll
     def read_status(self):
         return self._get_status(self.rawsensor.read_status())
+
+
+class SoftPiLoop(HasConvergence, PImixin, Sensor):
+    pass