[WIP] fi furnace improvements

- still under development

Change-Id: I5fc22f041fb136b549016f510f06ea703122bee5

frappy_psi/tdkpower.py

@@ -31,13 +31,13 @@ class IO(StringIO):
 
 class Power(HasIO, Readable):
     value = Parameter(datatype=FloatRange(0,3300,unit='W'))
-    
+    voltage = Parameter('voltage', FloatRange(0,8, unit='V'))
+    current = Parameter('current', FloatRange(0,400, unit='A'))
+
     def read_value(self):
-        reply_volt = self.communicate('MV?')
-        reply_current = self.communicate('MC?')
-        volt = float(reply_volt)
-        current = float(reply_current)
-        return volt*current
+        self.voltage = float(self.communicate('MV?'))
+        self.current = float(self.communicate('MC?'))
+        return self.voltage * self.current
 
     
 class Output(HasIO, Writable):
@@ -59,7 +59,7 @@ class Output(HasIO, Writable):
         # take care of proper order
         if target == 0:
             self.write_output_enable(False)
-        prev_curr = self.communicate(f'PC?')
+        prev_curr = float(self.communicate(f'PC?'))
         volt = self.maxvolt if self.mode == 'current' else self.maxvolt * 0.01 * target
         curr = self.maxcurrent if self.mode == 'voltage' else self.maxcurrent * 0.01 * target
         if curr < prev_curr: