Appendix D - Rs-232 Connection - Celestron C11-SGT Instruction Manual

Appendix D - RS-232 Connection

You can control your telescope with a computer via the RS-232 port on the computerized hand control and using an
optional RS-232 cable (#93920). Once connected, the telescope can be controlled using popular astronomy software
programs.
The Advanced GT communicates at 9600 bits/sec, No parity and a stop bit. All angles are communicated with 16 bit
angle and communicated using ASCII hexadecimal.
Description
Echo
Goto Azm-Alt
Goto Ra-Dec
Get Azm-Alt
Get RA-Dec
Cancel Goto
Is Goto in Progress
Is Alignment Complete
Commands below
available on version 1.6
or later
HC version
Stop/Start Tracking
32-bit goto RA-Dec
32-bit get RA-Dec
Commands below
available on version 2.2
or later
32-bit goto Azm-Alt
32-bit get Azm-Alt
The cable required to interface to the telescope
has an RS-232 male plug at one end and a 4-4
telephone jack at the other end. The wiring is
as follows:
PC Command ASCII Hand Control Response
Kx
B12AB, 4000
R34AB, 12CE
Z
E
M
L
J
V
Tx
x = 0 (Tracking off)
x = 1 (Alt-Az on)
x = 2 (EQ-N)
x = 3 (EQ-S)
r34AB0500,12CE0500
e
b34AB0500,12CE0500
z
Notes
X#
#
#
12AB, 4000#
34AB, 12CE#
#
0# or 1#
0# or 1#
2
2
#
#
34AB0500,12CE0500#
#
34AB0500,12CE0500#
62
Communication Protocol:
Useful to check communication
10 characters sent. B=Command,
12AB=Azm, comma, 4000=Alt. If
command conflicts with slew limits,
there will be no action.
Scope must be aligned. If
command conflicts with slew limits,
there will be no action.
10 characters returned,
12AB=Azm, comma, 4000=Alt, #
Scope must be aligned
0=No, 1=Yes; "0" is ASCII
character zero
0=No, 1=Yes
Two bytes representing V2.2
Alt-Az tracking requires alignment
The last two characters will always
be zero.
The last two characters will always
be zero.