Sky-Watcher Multi-Purpose Computerized Mount - Manual (Page 41)

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Additional RS-232 Commands
Sending a track rate through RS-232 to the hand control
1.
Multiply the desired tracking rate (arc seconds / second) by 4. For example: if the desired track rate is 120 arc seconds/second
(approximately 8 times of sidereal rate), then the TRACKRATE = 480.
2. Separate TRACKRATE into two bytes, such that ( TRACKRATE = TrackRateHighByte*256 + TrackRateLowByte).
For example TRACKRATE = 480, then TrackRateHighByte = 1, TrackRateLowByte = 224.
3. To send a tracking rate, send the following 8 bytes:
• Positive Azm tracking: 80, 3, 16, 6, TrackRateHighByte, TrackRateLowByte, 0, 0
• Negative Azm tracking: 80, 3, 16, 7, TrackRateHighByte, TrackRateLowByte, 0, 0
• Positive Alt tracking: 80, 3, 17, 6, TrackRateHighByte, TrackRateLowByte, 0, 0
• Negative Alt tracking: 80, 3, 17, 7, TrackRateHighByte, TrackRateLowByte, 0, 0
4. The number 35 is returned from the hand control.
Sending a slow-Goto command through RS232 to the hand control
1.
Convert the angle position to a 24-bit number. Example: if the desired position is 220, then POSITION_24BIT = (220/360)*224 =
10,252,743.
2. Separate
POSITION_24BIT into three bytes such that (POSITION_24BIT = PosHighByte * 65536 + PosMedByte * 256 +
PosLowByte). Example: PosHighByte = 156, PosMedByte = 113, PosLowByte = 199.
3.
Send the following 8 bytes:
• Azm Slow Goto: 80, 4, 16, 23, PosHighByte, PosMedByte, PosLowByte, 0
• Alt Slow Goto: 80, 4, 17, 23, PosHighByte, PosMedByte, PosLowByte, 0
4. The number 35 is returned from the hand control.
Resetting the position of Az or Alt
1.
Convert the angle position to a 24-bit number, same as Slow-Goto example.
2. Send the following 8 bytes:
• Azm Set Position: 80, 4, 16, 4, PosHighByte, PosMedByte, PosLowByte, 0
• Alt Set Position: 80, 4, 17, 4, PosHighByte, PosMedByte, PosLowByte, 0
3. The number 35 is returned from the hand control.