Appendix E - Rc2000C Communications Protocol - RESEARCH CONCEPTS RC2000C Manual

RC2000C Polar Tracking Antenna Controller

Appendix E - RC2000C Communications Protocol

Revision History
1.22.92 - Original communications protocol for the RC2000A derived from the RC1000A sabusext.inc file.
4.6.93 - Revised to document the new Auto Move to a target Az/El position command in the RC2000A version
1.30 software.
1.2.95 - Revised to document the new Auto Move to a target polarization position command and the new byte
32 function of the device status poll command reply in the RC2000A version 1.31 software.
3.21.95 - Revised for the RC2000A version 1.32 software which provided support for the high power
polarization option. The POL JAMMED and POL SENSOR alarm messages have been replaced with the ANT
POL alarm. The drive error status field of bytes 27 and 28 has been removed.
5.31.95 - Revised for the RC2000C version 1.00 inclined orbit satellite tracking software. Extra track status
information has been included in the device status pol reply. A track MISCELANEOUS command has been
included to set the frequency band for dual band satellites and to reset track errors.
11.6.95 - Revised for the RC2000C version 1.1x release. The only change in the comm protocol is the reply to
the Query Id command. The alarm codes that appear in this document have also been corrected.
OVERVIEW
The RC2000C command set conforms to the SA Bus protocol originally defined by Scientific Atlanta. This file
describes the commands used to implement the SA bus remote interface for the RC2000 antenna controller.
See the SA bus specification included with RC2000 manual for a complete description of the protocol.
RC 2000 BAUD RATE - ADDRESS SPECIFICATION
The baud rate and address must be set before communication with a host is possible. These quantities can be
specified in the CONFIG mode. The range of acceptable addresses is 49 to 111. The possible baud rate
values are 300, 600, 1200, 2400, 4800, or 9600. The usual SA Bus baud rate is 9600. For completeness, the
transmission parameters are repeated here: 7 data bits, even parity, 1 stop bit.
RC 2000 ONLINE/OFFLINE
To enable remote mode on the RC2000, the internal remote$mode$enable$flag must be set. This flag is set at
the 'REMOTE MODE ENABLE' prompt in CONFIG mode. When this flag is set, remote mode can be entered
in two ways. One way REMOTE mode can be activated by depressing the mode button. REMOTE mode can
be found just after AUTO mode. The second way REMOTE mode can be activated is when a valid command
arrives via the serial port. Certain commands can be processed by TRACK mode.
If the remote$mode$enable$flag is FALSE and a valid command arrives via the serial port, the offline reply is
sent to the host. Here is the format of the offline reply...
byte 0:
byte 1:
byte 2:
byte 3:
byte 4:
byte 5:
RC2000 UNRECOGNIZED COMMANDS - NAK REPLY
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas 66218-9680 • USA
ACK
A where A is the RC2000 address
'CC' the command code of the message which triggered this reply.
'F' Ascii 'F', for offline.
ETX
'chksum' the checksum. The checksum character is simply the bit-by-bit
exclusive OR of all characters in the message starting with the STX
character through the ETX character.
Appendix E Communications Protocol 79
www.researchconcepts.com