Index: firmware/App/Drivers/PeristalticPump.c
===================================================================
diff -u -r291d652fcd09b461728962a547d3b08163737d76 -rfc985a2080a265d14be32959fa41fb43318e4ff4
--- firmware/App/Drivers/PeristalticPump.c	(.../PeristalticPump.c)	(revision 291d652fcd09b461728962a547d3b08163737d76)
+++ firmware/App/Drivers/PeristalticPump.c	(.../PeristalticPump.c)	(revision fc985a2080a265d14be32959fa41fb43318e4ff4)
@@ -239,10 +239,19 @@
 
     if ( abs( rpm ) < MAX_PUMP_SPEED_RPM )
     {
-        F32 calRpm      = H4_PUMP_CMD_CAL( (F32)rpm );
-        U16 setRpm      = (U16)( abs( (S32)calRpm ) );
+        F32 calRpm;
+        U16 setRpm;
         MOTOR_DIR_T dir = MOTOR_DIR_FORWARD;
 
+        if ( rpm >= 0 )
+        {
+            calRpm = ( (F32)rpm * H4_PUMP_CMD_GAIN ) + H4_PUMP_CMD_OFFSET;
+        }
+        else
+        {
+            calRpm = ( (F32)rpm * H4_PUMP_CMD_GAIN ) - H4_PUMP_CMD_OFFSET;
+        }
+        setRpm = (U16)abs( (S32)calRpm );
         if ( rpm < 0 )
         {
             dir = MOTOR_DIR_REVERSE;