diff --git a/config/devices.properties b/config/devices.properties
index 907946d..cc3e05b 100644
--- a/config/devices.properties
+++ b/config/devices.properties
@@ -18,4 +18,4 @@ adc_xh1=ch.psi.pshell.epics.ChannelInteger|SARFE10-PBPG050:HAMP-014-x-h1-DATA-SU
 adc_yh2=ch.psi.pshell.epics.ChannelInteger|SARFE10-PBPG050:HAMP-011-y-h2-DATA-SUM|||true
 m2rx=ch.psi.pshell.epics.Motor|SAROP21-OOMV096:W_RX|||true
 #camtool=ch.psi.pshell.bs.Camtool|localhost:10000|||
-invalid=ch.psi.pshell.epics.ChannelDouble|SARUN15-UIND030:INVALID-PV -1 true Nullify|||true
+invalid1=ch.psi.pshell.epics.ChannelDouble|SARUN15-UIND030:INVALID-PV -1 true Nullify|||true
diff --git a/script/test/TestInvalid.py b/script/test/TestInvalid.py
index d313f0e..d02e95f 100644
--- a/script/test/TestInvalid.py
+++ b/script/test/TestInvalid.py
@@ -1,11 +1,33 @@
 import ch.psi.pshell.epics.ChannelDouble as ChannelDouble
 
+#Creating a timestamped channel (timestamp from the IOC) and accessing the severity 
+channel = ChannelDouble("test_inv1", "SARUN15-UIND030:INVALID-PV", -1, True)
+add_device(channel, True)
+print "Value=", test_inv1.read()
+print "Severity=", val.severity
 
-channel = ChannelDouble("test_inv", "SARUN15-UIND030:INVALID-PV", -1, True, InvalidValueAction.Nullify)
 
-avg = create_averager(channel, 5, interval = -1, name = "avg")
-avg.monitored = True
+#Creating a channel with PC timestamp from the IOC and accessing the severity atomically
+channel = ChannelDouble("test_inv2", "SARUN15-UIND030:INVALID-PV", -1, False, InvalidValueAction.None)
+add_device(channel, True)
+channel.read()
+val = channel.takeTimestamped()
+print "Value=", val.value
+print "Timestamp=", val.timestamp
+print "Severity=", val.severity
+
+
+#Creating a channel nullifying the invalid values and averaging next valid values in 5 following monitor values
+channel = ChannelDouble("test_inv3", "SARUN15-UIND030:INVALID-PV", -1, False, InvalidValueAction.Nullify)
 channel.monitored = True
+avg = create_averager(channel, 5, interval = -1, name = "test_avg_1")
+add_device(channel, True)
+add_device(avg, True)
+
+#Creating a channel ignoring the invalid values and an averager averaging next 5 valid monitor values.
+channel = ChannelDouble("test_inv4", "SARUN15-UIND030:INVALID-PV", -1, False, InvalidValueAction.Exception)
+channel.monitored = True
+avg = create_averager(channel, 5, interval = -1, name = "test_avg_2")
 add_device(channel, True)
 add_device(avg, True)