Operation and Maintenance Manual

end of each azimuth sweep. Changes of sign in RVA or RSA, or changes to
RCx or RRx may have the effect of placing the positioner outside the scan
limits, in which case it will scan until it reaches maximum position (MNx or
MXx) or a limit switch. Changes in RVA or RSA without a change in sign
are OK.
Two control bits which may affect scanning are the Fast Step bit (Control
Word #2, bit #6) and the Continuous Rotation bit (Control Word #1, Bit #5).
If the Fast Step bit is not set, the various step motions at the end of each
azimuth scan may not proceed at their maximum velocity. The user may
choose, according to his preference, for fastest completion of scanning or
smoother motions between azimuth scans.
If the Continuous Rotation bit is set for azimuth, all step motions at the end of
azimuth scanning will be in their shortest possible direction. Therefore, in
single direction scanning, the "return" motion will be in the same direction as
the scan for scans greater than 180 degrees.
If it is desired to scan in azimuth only; i.e., with no elevation motion, set both
the elevation step size (RSA) and range (RRE) to zero.
4.1.6.2 Elevation Raster Scan Mode
This mode is analogous to the Azimuth Raster Scan mode, with the roles of
the two axes reversed; ie., the positioner scans in elevation and steps in
azimuth.
When the Elevation Raster Scan mode is entered, the positioner
moves to the initial corner of the raster profile at the maximum velocity
(MVx). The initial corner is determined by the sign of the RVE and
RSE parameters. If RVE is positive, the initial corner is the CCW
corner in elevation. If RSE is positive, the initial corner is CCW in
azimuth.
After the initial corner is reached, the positioner scans in elevation with
azimuth constant until the end of the elevation range, and decelerates
to zero velocity.
If the RTE parameter is nonzero, it waits for a delay time as specified
by the RTE parameter.
If the bit for a single-direction raster is set (Control Word #2, bit 4), the
positioner then steps in azimuth an amount given by the RSE