diff --git a/pyedflib/highlevel.py b/pyedflib/highlevel.py
index 6b65664..938b6bc 100644
--- a/pyedflib/highlevel.py
+++ b/pyedflib/highlevel.py
@@ -479,6 +479,9 @@ def write_edf(edf_file, signals, signal_headers, header=None, digital=False,
         dmin, dmax = shead['digital_min'], shead['digital_max']
         pmin, pmax = shead['physical_min'], shead['physical_max']
         label = shead['label']
+        # physical resolution, acceptable rounding error if within this range
+        sig_res = abs((dmax-dmin)/(pmax-pmin)) 
+        
         if digital: # exception as it will lead to clipping
             assert dmin<=sig.min(), \
             'digital_min is {}, but signal_min is {}' \
@@ -489,12 +492,12 @@ def write_edf(edf_file, signals, signal_headers, header=None, digital=False,
             assert pmin != pmax, \
             'physical_min {} should be different from physical_max {}'.format(pmin,pmax)
         else: # only warning, as this will not lead to clipping
-            assert pmin<=sig.min(), \
-            'phys_min is {}, but signal_min is {} ' \
-            'for channel {}'.format(pmin, sig.min(), label)
-            assert pmax>=sig.max(), \
-            'phys_max is {}, but signal_max is {} ' \
-            'for channel {}'.format(pmax, sig.max(), label)
+            if pmin>=(sig.min()+sig_res):
+                warnings.warn('phys_min is {}, but signal_min is {} ' \
+                              'for channel {}'.format(pmin, sig.min(), label))
+            if pmax<=(sig.max()-sig_res):
+                warnings.warn('phys_max is {}, but signal_max is {} ' \
+                              'for channel {}'.format(pmax, sig.max(), label))
 
 
         frequency_key = 'sample_rate' if shead.get('sample_frequency') is None else 'sample_frequency'
diff --git a/pyedflib/tests/test_highlevel.py b/pyedflib/tests/test_highlevel.py
index 54f8e27..64d73b6 100644
--- a/pyedflib/tests/test_highlevel.py
+++ b/pyedflib/tests/test_highlevel.py
@@ -182,7 +182,7 @@ def test_read_write_diff_sfreq(self):
             np.testing.assert_allclose(s1, s2)
         
     def test_assertion_dmindmax(self):
-        
+        import warnings
         # test digital and dmin wrong
         signals =[np.random.randint(-2048, 2048, 256*60).astype(np.int32)]
         sheaders = [highlevel.make_signal_header('ch1', sample_frequency=256)]
@@ -196,9 +196,27 @@ def test_assertion_dmindmax(self):
         sheaders = [highlevel.make_signal_header('ch1', sample_frequency=256)]
         sheaders[0]['physical_min'] = -200
         sheaders[0]['physical_max'] = 200
-        with self.assertRaises(AssertionError):
+        with self.assertWarns(UserWarning):
             highlevel.write_edf(self.edfplus_data_file, signals, sheaders, digital=False)
             
+        signals = [np.random.randint(-2048, 2048, 256*60)]
+        sheaders = [highlevel.make_signal_header('ch1', sample_frequency=256)]
+        sheaders[0]['physical_min'] = np.min(signals)
+        sheaders[0]['physical_max'] = np.max(signals)
+        # should not give a warning as its within bounds
+        with self.assertRaises(AssertionError):
+            with self.assertWarns(UserWarning):
+                highlevel.write_edf(self.edfplus_data_file, signals, sheaders, digital=False)
+                
+        signals = [np.random.randint(-2048, 2048, 256*60)]
+        sheaders = [highlevel.make_signal_header('ch1', sample_frequency=256)]
+        sheaders[0]['physical_min'] = np.min(signals) - 0.01
+        sheaders[0]['physical_max'] = np.max(signals) + 0.01
+        # should not give a warning as its within bounds of resolution
+        with self.assertRaises(AssertionError):
+            with self.assertWarns(UserWarning):
+                highlevel.write_edf(self.edfplus_data_file, signals, sheaders, digital=False)
+                                                    
 
     def test_read_write_accented(self):
         signals = np.random.rand(3, 256*60) # then rescale to 0-1