diff --git a/iocBoot/iocvxWorks/dac128V.substitutions b/iocBoot/iocvxWorks/dac128V.substitutions
index 9fa7d76f51a15a21a40ff97c4d2097413114b7fc..e21e49c333ae8e49ad5886627ec4434b4a99e43f 100644
--- a/iocBoot/iocvxWorks/dac128V.substitutions
+++ b/iocBoot/iocvxWorks/dac128V.substitutions
@@ -1,12 +1,16 @@
 file "$(DAC128V)/dac128VApp/Db/singleDAC.db"
 {pattern
-{P,    D, N, S, PORT, EGUL,   EGUF, DRVL, DRVH, LOPR, HOPR, PREC,     LINR, VAL}
-{xxx:, 1, 1, 0, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 2, 1, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 3, 2, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 4, 3, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 5, 4, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 6, 5, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 7, 6, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
-{xxx:, 1, 8, 7, DAC1,   0,    65535, -10,  10,   -10,  10,   3,    "LINEAR", 0}
+{P,    D, N, S, PORT,   EGUL,  EGUF, DRVL, DRVH, LOPR, HOPR, PREC,     LINR, VAL}
+# Channel 1 is in volts, -10 to 10, with drive limits full range
+{xxx:, 3, 1, 0, DAC1,    -10,    10, -10,  10,   -10,  10,   3,    "LINEAR", 0}
+# Channel 2 is in volts, -10 to 10, but only allow driving 0 to 10
+{xxx:, 3, 2, 1, DAC1,    -10,    10,   0,  10,     0,  10,   3,    "LINEAR", 0}
+# Channel 3 is in percent of full scale, only allow driving 0 to 100%
+{xxx:, 3, 3, 2, DAC1,   -100,   100,   0, 100,     0, 100,   3,    "LINEAR", 0}
+# Remaing channels are in volts
+{xxx:, 3, 4, 3, DAC1,    -10,    10, -10,  10,   -10,  10,   3,    "LINEAR", 0}
+{xxx:, 3, 5, 4, DAC1,    -10,    10, -10,  10,   -10,  10,   3,    "LINEAR", 0}
+{xxx:, 3, 6, 5, DAC1,    -10,    10, -10,  10,   -10,  10,   3,    "LINEAR", 0}
+{xxx:, 3, 7, 6, DAC1,    -10,    10, -10,  10,   -10,  10,   3,    "LINEAR", 0}
+{xxx:, 3, 8, 7, DAC1,    -10,    10, -10,  10,   -10,  10,   3,    "LINEAR", 0}
 }