Campbell Scientific CS110 Electric Field Meter - Manual (Page 60)

Appendix D. Servicing the CS110
EndIf
If
Flag(2) Then
CS110Trim(-1) 'Take a step closed.
Flag(2) = 0 'Reset Flag 2.
EndIf
NextScan
EndProg
The CS110_Index_Trim.cr1 program uses flags 1, 2 and 3 available in
LoggerNet, for user control. Flags 1 and 2 are used to single step the shutter one
step open and closed, respectively. These flags are used initially to position the
shutter into the fully opened position, as observed visually by stator to shutter
overlap.
At least 8 consecutive open (flag 1) initiated motor steps should
occur prior to arriving at the fully open position in order to
guarantee synchronization between the motor controller phase
state and the stepper-motor coils being energized. NOTE
Stator to shutter overlap exists in the fully opened and fully closed positions so
that slight shutter position variations do not alter the measured result. A fully
opened shutter will display symmetrical stator to shutter overlap, within the 1.8
°
stepper motor step size, on both edges of each of the 4 openings in the stator.
Once the shutter has been adjusted to the fully open position by means of flags 1
and 2, flag 3 is to be set high to execute a 25 closed step loop, which positions
the shutter in the fully closed position, which is the desired position for the
Index trim. No visible gaps between the stator and shutter blades should be
visible in the fully closed shutter position. Once in the fully closed position,
hook an oscilloscope or dc voltmeter to the Index test pin on the CS110 panel
PCB. The Ports and Flags button on the LoggerNet connect screen along with a
graphical display can also be used for trimming if the update interval is set to 50
ms.
D-4