symetrie hexapod: "pmac" method only exists for 1st protocol version

bliss/controllers/motors/shexapod.py

@@ -251,7 +251,11 @@ Q86=%f Q87=%f Q88=%f Q89=%f Q90=%f Q91=%f Q20=21"
         except ValueError:
             raise TypeError("Need float values to define user and object origin")
 
-        self.protocol().pmac(cmd)
+        prot = self.protocol()
+        if isinstance(prot, HexapodProtocolV1):
+            prot.pmac(cmd)
+        else:
+            raise NotImplementedError
 
     def __info__(self):
         return self.get_info(None)