fix code for current framwork version

- remove _iodev, use HasIo instead of HasIodev
- add earlyInit super call

secop_psi/dpm.py

@@ -85,7 +85,7 @@ class DPM3(HasIO, Readable):
         else:
             cmd = ""
         cmd = cmd + '*1G3%02X' % adr
-        hexvalue = self._iodev.communicate(cmd)
+        hexvalue = self.communicate(cmd)
         if adr == self.SCALE:
             mag = self.MAGNITUDE[hexvalue[0:1]]
             value = int(hexvalue[1:], 16)
@@ -95,7 +95,7 @@ class DPM3(HasIO, Readable):
 
     def write_digits(self, value):
         # value defines the number of digits
-        back_value = self._iodev.communicate('*1F135%02X\r*1G135' % (value + 1))
+        back_value = self.communicate('*1F135%02X\r*1G135' % (value + 1))
         self.digits = int(back_value, 16) - 1
         # recalculate proper scale and offset
         self.write_scale_factor(self.scale_factor)
@@ -103,11 +103,11 @@ class DPM3(HasIO, Readable):
         return Done
 
     def read_digits(self):
-        back_value = self._iodev.communicate('*1G135')
+        back_value = self.communicate('*1G135')
         return int(back_value,16) - 1
 
     def read_value(self):
-        return float(self._iodev.communicate('*1B1'))
+        return float(self.communicate('*1B1'))
 
     def read_offset(self):
         reply = self.query(self.OFFSET)