diff --git a/imap_processing/idex/idex_variable_unpacking_and_eu_conversion.csv b/imap_processing/idex/idex_variable_unpacking_and_eu_conversion.csv
index 80927ecbe2..3206c3847d 100644
--- a/imap_processing/idex/idex_variable_unpacking_and_eu_conversion.csv
+++ b/imap_processing/idex/idex_variable_unpacking_and_eu_conversion.csv
@@ -1,33 +1,39 @@
-index,mnemonic,var_name,starting_bit,nbits_padding_before,unsigned_nbits,unit,c0,c1,c2,c3,c4,c5,c6,c7,convertAs,packetName
-1,current_1v_pol,idx__txhdrprochkch01,4,4,12,mA,0,0.9029253,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-2,current_1p9v_pol,idx__txhdrprochkch01,20,4,12,mA,0,0.9029253,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-3,temperature_1,idx__txhdrprochkch23,4,4,12,C,162.8276,-0.2668687,0.0003323794,-0.000000243153,9.034532e-11,-1.327735E-14,0,0,UNSEGMENTED_POLY,IDEX_SCI
-4,temperature_2,idx__txhdrprochkch23,20,4,12,C,162.8276,-0.2668687,0.0003323794,-0.000000243153,9.034532e-11,-1.327735E-14,0,0,UNSEGMENTED_POLY,IDEX_SCI
-5,voltage_1v_bus,idx__txhdrprochkch45,4,4,12,V,0,0.000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-6,fpga_temperature,idx__txhdrprochkch45,20,4,12,C,358.31,-0.1187104,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-7,voltage_1p9v_bus,idx__txhdrprochkch67,4,4,12,V,0,0.000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-8,voltage_3p3v_bus,idx__txhdrprochkch67,20,4,12,V,0,0.001611722,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-9,detector_voltage,idx__txhdrhvpshkch01,4,4,12,V,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-10,sensor_voltage,idx__txhdrhvpshkch01,20,4,12,V,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-11,target_voltage,idx__txhdrhvpshkch23,4,4,12,V,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-12,rejection_voltage,idx__txhdrhvpshkch23,20,4,12,V,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-13,reflectron_voltage,idx__txhdrhvpshkch45,4,4,12,V,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-14,current_hvps_sensor,idx__txhdrhvpshkch45,20,4,12,mA,0,0.000007326,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-15,positive_current_hvps,idx__txhdrhvpshkch67,4,4,12,mA,0,0.000024339,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-16,negative_current_hvps,idx__txhdrhvpshkch67,20,4,12,mA,0,0.000024339,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-17,voltage_3p3_ref,idx__txhdrlvhk0ch01,4,4,12,V,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-18,voltage_3p3_op_ref,idx__txhdrlvhk0ch01,20,4,12,V,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-19,voltage_neg6v_bus,idx__txhdrlvhk0ch23,4,4,12,V,-33,0.00886447,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-20,voltage_pos6v_bus,idx__txhdrlvhk0ch23,20,4,12,V,0,0.00241758,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-21,voltage_pos16v_bus,idx__txhdrlvhk0ch45,4,4,12,V,0,0.00482711,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-22,voltage_pos3p3v_bus,idx__txhdrlvhk0ch45,20,4,12,V,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-23,voltage_neg5v_bus,idx__txhdrlvhk0ch67,4,4,12,V,-33,0.00886447,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-24,voltage_pos5v_bus,idx__txhdrlvhk0ch67,20,4,12,V,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-25,current_3p3v_bus,idx__txhdrlvhk1ch01,4,4,12,A,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-26,current_16v_bus,idx__txhdrlvhk1ch01,20,4,12,A,0,0.000161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-27,current_6v_bus,idx__txhdrlvhk1ch23,4,4,12,A,0,0.0000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-28,current_neg6v_bus,idx__txhdrlvhk1ch23,20,4,12,A,0,-0.0000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-29,current_5v_bus,idx__txhdrlvhk1ch45,4,4,12,A,0,0.00004029304,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-30,current_neg5v_bus,idx__txhdrlvhk1ch45,20,4,12,A,0,-0.0000201465,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-31,current_2p5v_bus,idx__txhdrlvhk1ch67,4,4,12,A,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
-32,current_neg2p5v_bus,idx__txhdrlvhk1ch67,20,4,12,A,0,-0.000040293,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
\ No newline at end of file
+index,mnemonic,var_name,starting_bit,nbits_padding_before,unsigned_nbits,unit,dn_range_start,dn_range_stop,c0,c1,c2,c3,c4,c5,c6,c7,convertAs,packetName
+1,current_1v_pol,idx__txhdrprochkch01,4,4,12,mA,,,0,0.9029253,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+2,current_1p9v_pol,idx__txhdrprochkch01,20,4,12,mA,,,0,0.9029253,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+3,temperature_1,idx__txhdrprochkch23,4,4,12,C,0,2063,162.8276,-0.2668687,0.0003323794,-2.43153e-07,9.034532e-11,-1.327735e-14,0,0,SEGMENTED_POLY,IDEX_SCI
+4,temperature_1,idx__txhdrprochkch23,4,4,12,C,2064,3853,714.2124,-1.194011,0.0008599094,-3.145266e-07,5.745416e-11,-4.208231e-15,0,0,SEGMENTED_POLY,IDEX_SCI
+5,temperature_1,idx__txhdrprochkch23,4,4,12,C,3854,4051,136881.2,-105.4644,0.02710281,-2.323543e-06,0,0,0,0,SEGMENTED_POLY,IDEX_SCI
+6,temperature_1,idx__txhdrprochkch23,4,4,12,C,4052,4095,-100809.9,50.03809,-0.00621209,0,0,0,0,0,SEGMENTED_POLY,IDEX_SCI
+7,temperature_2,idx__txhdrprochkch23,20,4,12,C,0,2063,162.8276,-0.2668687,0.0003323794,-2.43153e-07,9.034532e-11,-1.327735e-14,0,0,SEGMENTED_POLY,IDEX_SCI
+8,temperature_2,idx__txhdrprochkch23,20,4,12,C,2064,3853,714.2124,-1.194011,0.0008599094,-3.145266e-07,5.745416e-11,-4.208231e-15,0,0,SEGMENTED_POLY,IDEX_SCI
+9,temperature_2,idx__txhdrprochkch23,20,4,12,C,3854,4051,136881.2,-105.4644,0.02710281,-2.323543e-06,0,0,0,0,SEGMENTED_POLY,IDEX_SCI
+10,temperature_2,idx__txhdrprochkch23,20,4,12,C,4052,4095,-100809.9,50.03809,-0.00621209,0,0,0,0,0,SEGMENTED_POLY,IDEX_SCI
+11,voltage_1v_bus,idx__txhdrprochkch45,4,4,12,V,,,0,0.000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+12,fpga_temperature,idx__txhdrprochkch45,20,4,12,C,,,358.31,-0.1187104,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+13,voltage_1p9v_bus,idx__txhdrprochkch67,4,4,12,V,,,0,0.000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+14,voltage_3p3v_bus,idx__txhdrprochkch67,20,4,12,V,,,0,0.001611722,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+15,detector_voltage,idx__txhdrhvpshkch01,4,4,12,V,,,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+16,sensor_voltage,idx__txhdrhvpshkch01,20,4,12,V,,,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+17,target_voltage,idx__txhdrhvpshkch23,4,4,12,V,,,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+18,rejection_voltage,idx__txhdrhvpshkch23,20,4,12,V,,,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+19,reflectron_voltage,idx__txhdrhvpshkch45,4,4,12,V,,,0,1.4652,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+20,current_hvps_sensor,idx__txhdrhvpshkch45,20,4,12,mA,,,0,0.000007326,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+21,positive_current_hvps,idx__txhdrhvpshkch67,4,4,12,mA,,,0,0.000024339,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+22,negative_current_hvps,idx__txhdrhvpshkch67,20,4,12,mA,,,0,0.000024339,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+23,voltage_3p3_ref,idx__txhdrlvhk0ch01,4,4,12,V,,,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+24,voltage_3p3_op_ref,idx__txhdrlvhk0ch01,20,4,12,V,,,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+25,voltage_neg6v_bus,idx__txhdrlvhk0ch23,4,4,12,V,,,-33,0.00886447,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+26,voltage_pos6v_bus,idx__txhdrlvhk0ch23,20,4,12,V,,,0,0.00241758,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+27,voltage_pos16v_bus,idx__txhdrlvhk0ch45,4,4,12,V,,,0,0.00482711,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+28,voltage_pos3p3v_bus,idx__txhdrlvhk0ch45,20,4,12,V,,,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+29,voltage_neg5v_bus,idx__txhdrlvhk0ch67,4,4,12,V,,,-33,0.00886447,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+30,voltage_pos5v_bus,idx__txhdrlvhk0ch67,20,4,12,V,,,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+31,current_3p3v_bus,idx__txhdrlvhk1ch01,4,4,12,A,,,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+32,current_16v_bus,idx__txhdrlvhk1ch01,20,4,12,A,,,0,0.000161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+33,current_6v_bus,idx__txhdrlvhk1ch23,4,4,12,A,,,0,0.0000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+34,current_neg6v_bus,idx__txhdrlvhk1ch23,20,4,12,A,,,0,-0.0000805861,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+35,current_5v_bus,idx__txhdrlvhk1ch45,4,4,12,A,,,0,0.00004029304,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+36,current_neg5v_bus,idx__txhdrlvhk1ch45,20,4,12,A,,,0,-0.0000201465,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+37,current_2p5v_bus,idx__txhdrlvhk1ch67,4,4,12,A,,,0,0.00161172,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
+38,current_neg2p5v_bus,idx__txhdrlvhk1ch67,20,4,12,A,,,0,-0.000040293,0,0,0,0,0,0,UNSEGMENTED_POLY,IDEX_SCI
diff --git a/imap_processing/tests/test_utils.py b/imap_processing/tests/test_utils.py
index f1e5ded165..34c5502bff 100644
--- a/imap_processing/tests/test_utils.py
+++ b/imap_processing/tests/test_utils.py
@@ -32,13 +32,13 @@ def test_convert_raw_to_eu(tmp_path):
             ],
             "dn_range_start": [0, 0, 1, dn_cutoff + 1, 0],
             "dn_range_stop": [0, 0, dn_cutoff, 4, 0],
-            "c0": [0, 1, 3, 4, 2],
-            "c1": [0, 1, 3, 4, 2],
-            "c2": [0, 0, 3, 4, 2],
-            "c3": [0, 0, 3, 4, 2],
-            "c5": [0, 1, 3, 4, 2],
-            "c6": [0, 0, 3, 4, 2],
-            "c7": [0, 0, 3, 4, 2],
+            "c0": [0, 1, -3.5, 1.5, 2],
+            "c1": [0, 1, 0.25, -0.75, 2],
+            "c2": [0, 0, 0, 4, 2],
+            "c3": [0, 0, 0, 0, 2],
+            "c5": [0, 1, 0, 0, 2],
+            "c6": [0, 0, 0, 0, 2],
+            "c7": [0, 0, 0, 0, 2],
             "unit": ["a", "b", "d", "d", "c"],
         }
     )
@@ -49,9 +49,11 @@ def test_convert_raw_to_eu(tmp_path):
 
     # Generate a fake dataset for testing
     n_packets = 3
-    field_0 = np.arange(n_packets)
-    field_1 = np.arange(n_packets) + 10
-    field_2 = np.arange(n_packets) + 1
+    field_0 = np.arange(n_packets).astype(
+        np.uint16
+    )  # Use unsigned integer to mock packet data.
+    field_1 = np.arange(n_packets).astype(np.uint16) + 10
+    field_2 = np.arange(n_packets).astype(np.uint16) + 1
     time = np.arange(n_packets) + 1000
     dn_dataset = xr.Dataset(
         data_vars=dict(
diff --git a/imap_processing/utils.py b/imap_processing/utils.py
index 72d76f8f4a..94b60b3b03 100644
--- a/imap_processing/utils.py
+++ b/imap_processing/utils.py
@@ -113,7 +113,9 @@ def convert_raw_to_eu(
             dataset[var].data = np.polyval(coeff_values, dataset[var].data)
 
         elif np.all(packet_df["convertAs"] == "SEGMENTED_POLY"):
-            data = dataset[var].data
+            # np.piecewise output takes the input dtype, so cast to float to avoid
+            # truncating (or wrapping negative) values for integer raw DNs
+            data = dataset[var].data.astype(np.float64)
             # Check if any of the raw DN values fall outside the ranges
             bad_mask = np.logical_or(
                 data < packet_df["dn_range_start"].min(),