Operation and Maintenance Manual

parameter and returns to the elevation starting point, both together at
maximum velocity, and the elevation scan repeats.
If the single-direction bit is cleared, the azimuth steps and the elevation
scans in reverse.
The process is repeated until the next azimuth step results in
exceeding the range specified in the RRA parameter. At this point, if
the Non-Stop Raster bit (Control Word #2, bit 5) is set, the positioner
returns to the initial corner and the process is repeated.
If Non-Stop Raster is cleared, the positioner enters Standby mode at
the end of the scan.
Note that parameters may be changed in the middle of a scan, but this should
be done with caution. The parameter change will normally take effect at the
end of each elevation sweep. Changes of sign in RVE or RSE, 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 RVE or RSE 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 elevation 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 elevation scans.
If the Continuous Rotation bit is set for elevation, all step motions at
the end of elevation scanning will be in their shortest possible direction.
If it is desired to scan in elevation only; ie., with no azimuth motion, set
both the azimuth step size (RSE) and range (RRA) to zero.
4.2 Serial Protocol - Data Link Level
Serial communication uses asynchronous protocol with 8-bit word length, 1
start bit, 1 stop bit, even parity, and a rate of 9600 baud. Signal levels are RS-
232.