Research Concepts RC2000C - Manual (Page 95)

RC2000C Az/El Tracking Antenna Controller Appendix E Communications Protocol 87
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For the Polarotor, the polarization position value reported via the user interface
and the comm port (bytes 24 and 25 of the device status pol command reply) is
a value in the range of 0 to 98, 'CW' (for clockwise limit) or 'CC' (for counter
clockwise limit). The controller's internal polarization position representation,
however, is a value in the range of 0 to 661. An internal position of 0
corresponds to the CW limit and an internal position of 661 corresponds to the
CC limit. Internal position values in range of 1 to 660 are scaled to display as a
value of 0 to 98 on both the user interface and via bytes 24 and 25 of the
device status poll reply. To obtain the internal position from this byte and bytes
24 and 25, use the following formula ...
internal_position = ((byte_24_25_position * 661) / 99) + ls_nibble_byte_32
where ...
internal_position ... is the controller's internal Polarotor position representation.
byte_24_25_position ... is the Polarotor position reported via byte 24 and 25 of
the device status poll reply and displayed on the user interface (a value in the
range of 0 to 98).
ls_nibble_byte_32 ... is the least significant nibble (lower 4 bits) of this byte.
Note that in the above equation the division is an integer division which means
that the result of the division should be rounded DOWN to the closest integer
value (i.e. (39 * 661) / 99 = 260).
When a Polarotor is present in the system the upper nibble of byte 32 will be
'0010'.
For the rotating feed, the internal polarization position and the polarization
position displayed via the user interface are the same and will be a value in the
range of 0 to 1023. For the rotating feed the user is prompted to set CW and
CC limits. When the polarization position is less than or equal to the CW limit
specified by the user the 'CW' banner will be displayed. When the polarization
position is greater than or equal to the CC limit specified by the user, the CC
banner will be displayed.
The polarization position given by bytes 24 and 25 of the device status poll
reply will be a value in the range of 0 to 92. When the rotating feed is at a limit
(or beyond) the byte 24,25 values will be 'CW' or 'CC'. To obtain the internal
polarization position for the rotating feed from this byte and the value in bytes
24 and 25, use the following formula ...
internal_position = (byte_24_25_position * 11) + ls_nibble_byte_32
where the variables are as defined for the Polarotor case. Note that when a
rotating feed is present in the system, the upper nibble of byte 32 will be '0011'.
byte 33: Track Mode submode or error status and track frequency band.
7 6 5 4 $ 3 2 1 0
- - - - - - - -
0 1 b1 b0 $ s s s s
where