Added the capacitance reading device (based on TSSOP16, paired with an Arduino Nano V3, communication over serial) to the PSI NMR setup

frappy_psi/capacitance_readings/TSSOP16.py

@@ -0,0 +1,20 @@
+import serial
+
+from frappy.core import Readable, Parameter, FloatRange, HasIO, StringIO, Property, IntRange, IDLE, BUSY, WARN, ERROR, Drivable, BoolType, Attached
+
+class TSSOP16_IO(StringIO):
+    end_of_line = '\r'
+    identification = [ ('*IDN?', r'0x48,ACM1219,.*') ]
+    
+class TSSOP16(HasIO, Readable):
+    '''only configured for channel 1'''
+    
+    ioClass = TSSOP16_IO
+    value = Parameter('capacitance', FloatRange(unit='pF'), readonly=True)
+    pollinterval = Parameter(default=0.1)
+    
+    def read_value(self):
+        l = self.communicate('readCVT')
+        vals = l.split(',')
+        vals = [ float(v) for v in vals ]
+        return vals[0]