lakeshore: fix get_calib_state

+ relax curve check criterium (a better approach is WIP)

frappy_psi/lakeshore.py

@@ -257,7 +257,7 @@ class Device(HasLscIO, Module):
 
     def get_calib_state(self, sensor):
         if not self.io.is_connected:
-            return ERROR, 'no connection'
+            return CommunicationError('no connection')
         req = self._requests.get(sensor.calcurve)
         if req:
             if req.loading:
@@ -422,7 +422,7 @@ class Device(HasLscIO, Module):
         """write header"""
         self.command(f'CRVHDR {curve_no}', name, sn or '_', fmt, limit, coef)
 
-    def is_equal(self, left, right, fixeps=(1.1e-5, 1.1e-5), significant=6):
+    def is_equal(self, left, right, fixeps=(1.1e-4, 1.1e-4), significant=4):
         """check whether a returned calibration point is equal within curve point precision"""
         for v1, v2, eps in zip(left, right, fixeps):
             try: