-"BAD NMR" flag is set if at least one of the 4 NMR status (locked and stable, before and after) is wrong
-the full NMR field measurement is made of 3 successive elementary measurements separated by a 5s delay.
-the "lock" status is set to wrong if at least one of the 3 NMR measurements did not lock before a 100s timeout. The measurement sequence is aborted as soon as a measurement does not lock, so the maximum time one has to wait for a full NMR measurement is about 100s (in case of a zero current measurement for example)
-the "stable" status is set to wrong if the 2nd or the 3rd field values differs from the 1st by more than 5 10-4 relative. In any case, the field value returned is the last one.
-"In position" is set to false if the probe position was outside 1604.0+-0.1mm at NMR measurement time.
-"PDI saturation": the PDI (Mertolab's Precision Digital Integrator) consists in a programmable amplifier and a VFC integrator working in the [-5V, +5V] input range. The PDI gain is the result of an automatic selection in the [1,2,5,10,...1000] range, similar to the NMR probe selection. In case of a wrong gain selection (maximum voltage after gain, as plotted in the MEDM screen, outside the [1.5V,5V[ range), call the "arc_pdi.adl" MEDM screen to switch the gain selection mode from "auto" to "manual" and then select manuallay the gain. Return to "auto" mode before leaving the integral measurement.
-"before" and "after" data must be very
close: 
0.1 C difference for the temperatures of a given probe, <0.1A for the
currents and <10-5 for the field.
-plots: the blue curves are from forward pass, yellow ones for backward pass.
-the top plot gives the probe velocity (in m/s) as function of its position (in mm). The forward velocity should be +0.6m/s everywhere except at the center where it is reduced to +0.06m/s. The backward velocity plot should be the mirror image of the forward ons (-0.6 and -0.06m/s)
-the bottom plot gives the coil voltage after gain (in V) as function of the
probe position (in mm). It should be a null voltage everywhere except a set
of oscillation at the center. The backward voltage plot should be the mirror
image of the forward one (V-
-V). See "PDI saturation" above.
-to zoom a MEDM plot, see "Details on gain adjustment (scanners)" above.