offset unipolar ground observable targets half a bit above zero

diff --git a/comedi_calibrate/ni.c b/comedi_calibrate/ni.c
index a8c3ba9c24756ac6cb22f18a63359e09ac554a47..f6f1ee160f3374ff1f7f1d08f07073619ecc044e 100644 (file)
--- a/comedi_calibrate/ni.c
+++ b/comedi_calibrate/ni.c
@@ -268,6 +268,14 @@ static void ni_setup_observables( calibration_setup_t *setup )
        o->target = voltage_reference;
 
        if(unipolar_lowgain>=0){
+               comedi_range *range;
+               int max_data;
+
+               range = comedi_get_range( setup->dev, setup->ad_subdev, 0, unipolar_lowgain );
+                       assert( range != NULL );
+               max_data = comedi_get_maxdata( setup->dev, setup->ad_subdev, 0 );
+               assert( max_data > 0 );
+
                o = setup->observables + ni_unip_zero_offset_low;
                o->name = "ai, unipolar zero offset, low gain";
                o->observe_insn = tmpl;
@@ -275,7 +283,7 @@ static void ni_setup_observables( calibration_setup_t *setup )
                        CR_PACK(REF_GND_GND,unipolar_lowgain,AREF_OTHER)
                        | CR_ALT_SOURCE | CR_ALT_FILTER;
                o->reference_source = REF_GND_GND;
-               o->target = 0.0;
+               o->target = comedi_to_phys( 1, range, max_data ) / 2.0;
 
                o = setup->observables + ni_unip_reference_low;
                o->name = "ai, unipolar voltage reference, low gain";
@@ -289,6 +297,14 @@ static void ni_setup_observables( calibration_setup_t *setup )
 
        if(unipolar_highgain >= 0)
        {
+               comedi_range *range;
+               int max_data;
+
+               range = comedi_get_range( setup->dev, setup->ad_subdev, 0, unipolar_highgain );
+                       assert( range != NULL );
+               max_data = comedi_get_maxdata( setup->dev, setup->ad_subdev, 0 );
+               assert( max_data > 0 );
+
                o = setup->observables + ni_unip_zero_offset_high;
                o->name = "ai, unipolar zero offset, high gain";
                o->observe_insn = tmpl;
@@ -296,7 +312,7 @@ static void ni_setup_observables( calibration_setup_t *setup )
                        CR_PACK(REF_GND_GND,unipolar_highgain,AREF_OTHER)
                        | CR_ALT_SOURCE | CR_ALT_FILTER;
                o->reference_source = REF_GND_GND;
-               o->target = 0.0;
+               o->target = comedi_to_phys( 1, range, max_data ) / 2.0;
        }
 
        if(setup->da_subdev>=0){