New driver for AC Resistance Bridge (with SIM921 modules)

Change-Id: I2c2da421453af0f41703805092423f9b02d1f9b4

frappy_psi/bridge.py

@@ -0,0 +1,119 @@
+# *****************************************************************************
+# 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: Oksana Shliakhtun <oksana.shliakhtun@psi.ch>
+# *****************************************************************************
+
+import re
+from frappy.core import HasIO, Readable, Drivable, Parameter, FloatRange, IntRange, EnumType, \
+    Enum
+
+
+class BridgeIO(HasIO):
+    end_of_line = b'\r'  # should be <lf> or <cr>
+    identification = [('*IDN?', r'Stanford_Research_Systems,.*')]
+
+    def comm(self, port, cmd):
+        self.communicate(f'conn {port}')
+        return self.communicate(f'send {port}, "{cmd}\r"')
+
+    def set_par(self, cmd, *args):
+        head = ','.join([cmd] + [a if isinstance(a, str) else f'{a:g}' for a in args])
+        tail = cmd.replace(' ', '? ')
+        new_tail = re.sub(r'[0-9.]+', '', tail)
+
+        reply = self.comm(f'{head};{new_tail}')
+        result = []
+        for num in reply.split(','):
+            try:
+                result.append(float(num))
+            except ValueError:
+                result.append(num)
+        if len(result) == 1:
+            return result[0]
+        return result
+
+    def get_par(self, cmd):
+        reply = self.comm(cmd)
+        result = []
+        for num in reply.split(','):
+            try:
+                result.append(float(num))
+            except ValueError:
+                result.append(num)
+        if len(result) == 1:
+            return result[0]
+        return result
+
+
+class SIM921(BridgeIO, Readable, Drivable):
+    #port = Parameter()
+    value = Parameter('temperature', unit='K')
+    setpoint = Parameter('temperature deviation', datatype=FloatRange, unit='K')
+    resistance = Parameter('resistance', datatype=FloatRange, unit='ohm')
+    irange = Parameter('resistance range index', IntRange)
+    phase = Parameter('phase', FloatRange, unit='ang')
+    tc = Parameter('time constant', FloatRange)
+    autorange = Parameter('autorange_on', EnumType('autorange', off=0, soft=1, hard=2),
+                          readonly=False, default=0)
+
+
+    ioClass = BridgeIO
+
+    def read_resistance(self):
+        return self.get_par('rval')
+
+    def read_value(self):
+        return self.get_par('tval')
+
+    def read_phase(self):
+        return self.get_par('phase')
+
+    def read_setpoint(self):
+        return self.get_par('tset')
+
+    def write_setpoint(self, setpoint):
+        return self.comm(f'tset {setpoint}')
+
+    def read_tc(self):
+        return self.get_par('tcon')
+
+    def write_tc(self, tc):
+        return self.set_par(f'tcon {tc}')
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+