diff --git a/Packages/MIES/MIES_DAEphys.ipf b/Packages/MIES/MIES_DAEphys.ipf
index ae9f2461ba..674fec6593 100644
--- a/Packages/MIES/MIES_DAEphys.ipf
+++ b/Packages/MIES/MIES_DAEphys.ipf
@@ -5611,8 +5611,12 @@ Function [variable minimum, variable maximum] DAP_GetDataLimits(string device, v
 	variable minVolt, maxVolt, gain, hardwareType, DAC, minStimset, maxStimset, activeDACIndex
 	string ctrl, text, msg
 
+	if(DAP_DeviceIsUnLocked(device))
+		return [NaN, NaN]
+	endif
+
 	DAC = AFH_GetDACFromHeadstage(device, headstage)
-	if(IsNaN(DAC))
+	if(!IsValidHeadstage(DAC))
 		return [NaN, NaN]
 	endif
 
@@ -5632,7 +5636,6 @@ Function [variable minimum, variable maximum] DAP_GetDataLimits(string device, v
 	WAVE DAQConfigWave = GetDAQConfigWave(device)
 	WAVE DACs          = GetDACListFromConfig(DAQConfigWave)
 	activeDACIndex = GetRowIndex(DACs, val = DAC)
-	ASSERT(IsFinite(activeDACIndex), "Invalid DAC")
 
 	WAVE gains = SWS_GetChannelGains(device, timing = GAIN_BEFORE_DAQ)
 	gain = gains[activeDACIndex]
diff --git a/Packages/tests/HardwareBasic/UTF_BasicHardwareTests.ipf b/Packages/tests/HardwareBasic/UTF_BasicHardwareTests.ipf
index 0734bb1985..207f1a763e 100644
--- a/Packages/tests/HardwareBasic/UTF_BasicHardwareTests.ipf
+++ b/Packages/tests/HardwareBasic/UTF_BasicHardwareTests.ipf
@@ -2491,3 +2491,60 @@ static Function TestCustomElectrodeNamesInNWB_REENTRY([string str])
 	CHECK_EQUAL_VAR(GetSetVariable(str, "SetVar_Sweep"), 1)
 	TestNwbExportV2()
 End
+
+// UTF_TD_GENERATOR DeviceNameGeneratorMD1
+static Function GetDataLimitsChecksWorks([string str])
+
+	variable minimum, maximum
+
+	// unlocked device
+	[minimum, maximum] = DAP_GetDataLimits(str, 1, "StimulusSetA_DA_0", 0)
+	CHECK(IsNaN(minimum))
+	CHECK(IsNaN(maximum))
+
+	STRUCT DAQSettings s
+	InitDAQSettingsFromString(s, "MD1_RA1_I0_L0_BKG1_TP1"                  + \
+	                             "__HS1_DA1_AD2_CM:IC:_ST:StimulusSetA_DA_0:")
+
+	AcquireData_NG(s, str)
+
+	CtrlNamedBackGround StopTPAfterSomeTime, start=(ticks + 120), period=60, proc=StopTP_IGNORE
+End
+
+static Function GetDataLimitsChecksWorks_REENTRY([string str])
+
+	string stimset
+	variable minimum, maximum, headstage
+
+	headstage = 1
+	stimset   = "StimulusSetA_DA_0"
+
+	// unassociated/unused headstage
+	[minimum, maximum] = DAP_GetDataLimits(str, 0, stimset, 0)
+	CHECK(IsNaN(minimum))
+	CHECK(IsNaN(maximum))
+
+	// invalid setColumn
+	try
+		[minimum, maximum] = DAP_GetDataLimits(str, headstage, stimset, 4711)
+		FAIL()
+	catch
+		CHECK_NO_RTE()
+	endtry
+
+	[minimum, maximum] = DAP_GetDataLimits(str, headstage, stimset, 0)
+	CHECK_EQUAL_VAR(minimum, -Inf)
+	CHECK_EQUAL_VAR(maximum, 4095)
+
+	// @todo more proper test cases
+
+	// third party
+	WB_MakeStimsetThirdParty(stimset)
+
+	try
+		[minimum, maximum] = DAP_GetDataLimits(str, headstage, stimset, 0)
+		FAIL()
+	catch
+		CHECK_NO_RTE()
+	endtry
+End
diff --git a/Packages/tests/UTF_HardwareHelperFunctions.ipf b/Packages/tests/UTF_HardwareHelperFunctions.ipf
index fe40fbc167..373b56c724 100644
--- a/Packages/tests/UTF_HardwareHelperFunctions.ipf
+++ b/Packages/tests/UTF_HardwareHelperFunctions.ipf
@@ -1293,7 +1293,9 @@ Function InitDAQSettingsFromString(s, str)
 				continue
 			endif
 
-			headstage       = ParseNumber(elem, "HS")
+			headstage = ParseNumber(elem, "HS")
+			REQUIRE(IsValidHeadstage(headstage))
+
 			s.hs[headstage] = 1
 
 			s.da[headstage] = ParseNumber(elem, "_DA")