Stellar Observations Network Group (SONG): SONG in New Mexico

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====== Telescope and observatory control system ======

===== Telescope control system ======

Telescope is a Planewave PW1000. It is controlled through the pwi1m computer in the 1m dome, running Windows. pwi1m has two network interfaces. One connects to the telescope internal network on 192.168.10.XXX. pwi1m is 192.168.10.40, the Maestro controller on the telescope is 192.168.10.50, and the OTA controller on the telescope is 192.168.10.60.

Software control is through Planewave's PWI4 software. This runs  under Windows on pwi1m , and provides a graphical user interface, as well as an ASCOM driver and also a custom Planewave HTTP API.

Normal telescope control is done remotely through the ASCOM interface, but interacting with PWI4 directly provide additional functionality. In particular, PWI4 incorporates its own pointing model software.

The telescope ASCOM driver should be registered through ASCOM Remote to make it available through an ASCOM/Alpaca interface.

===== Camera control system =====

Acquisition camera is connected to pwi1m via USB. PWI4 has the capability to connect to an ASCOM camera, and this is needed for doing pointing models

Normal camera control is done remotely throught the ASCOM interface. The camera ASCOM driver should be registered through ASCOM Remote to make it available through an ASCOM/Alpaca interface.

===== Observatory control system ======

==== Dome hardware ====

The dome has motorized upper and lower slit sections. Control of the upper slit and dome rotation is done through a custom relay box on the S side of the dome constructed by the Autoscope Corporation; the lower slit is controlled through a box on the N side, designed and constructed by Dave Woods. There is a manual/automatic toggle to allow dome control either through switches on the side of the boxes, or via remote control. Relays to control the dome motors are 24V relays and are activated by setting input control lines to ground. The 24V power is supplied externally.

There is an encoder coupled to the motor drive shaft.

There is a magnetic home sensor installed on the E side of the dome; the home position when the magnet on the dome lines up with the sensor places the slit at an azimuth of 80 degrees.

==== Dome control ====

Dome control is implemented through software running on a Raspberry Pi, dome1m. Initial implementation controls dome motors through the Autoscope box with Opto 22 relays, but goal would be to just control the dome relays directly. The Raspberry Pi has a RELAYPlates card with 7 relays, which control shutter direction, shutter power, dome direction, dome power, and watchdog reset. These relays connect the control lines to ground.

The dome encoder gets +5V and ground from the RPi, and receives 5VDC signals from the A and B phases of the quadrature encoder. These are wired into RPi GPIO ports through a level converter that converts 5V to 3.3V. DC +5 and ground are connected to RPi power, A and B outputs are connected to level shifter input channels; level shifter output channels are connected to RPi GPIO pins. An independent ground from the
cable shield may be very important, do not ignore!

| Encoder pin | function | AMP pin | RPi/level shifter color | connection |
| 1 | +5VDC | 1 | red | RPi +5V   | 
| 2 | gnd   | 2 | blk | RPi Gnd | 
| 3 | Bbar  | 3 | grn | B4 - A4 - GPIO 13 |
| 4 | B     | 4 | yel | B3 - A3 - GPIO 12 |
| 5 | Zbar  | 5 |     |  |
| 6 | Z     | 6 |     |  |
| 7 | Abar  | 7 | org | B2 - A2 - GPIO 6 |
| 8 | A     | 8 | brn | B1 - A1 - GPIO 5 |
|   | shield| 9 | grey | independent ground |

The home sensor gets +5VDC and ground from the RPi, and receives a signal on a GPIO port that is normally low, but goes high when the home magnet is in proximity to the sensor.S
| Sensor wire | function | circular connector pin | RPi/level shifter color | connection |
|     | shield| 1 | gry | independent ground|
| blk | signal| 2 | blu | B5 - A5 - GPIO 16 |
| red | gnd   | 3 | blk | RPi gnd |
| grn | +DC   | 4 | red | RPi +5V |

J808A : Watchdog: Dome box needs +24V or else it will close
| Dome box |         |  Peltec timer
| 1        | gnd     |    18   |   16  |   gnd |
| 3        | +24V DC |    28   |   26  |  +24V |
|          |         |    A1   |  gnd
|          |         |    A2   |  RPI relay |  +24V |

J805A : Dome power org yel blu
4 | +24V
3 | gnd
2 | relay 1 gry

J806A : Dome direction brn red grn
4 | +24
3 | gnd
2 | relay 3 brn

J807A : Shutter power 
2 : relay 2 pur
3 : gnd
4 : relay 4 org
5 : gnd

OCS |  RPi |
50 grn  | 5 | watchdog
49 Pur  | 7 |
48 org  | 2 | shutter power
47 yel  | 1 | dome power
2  blu  | 6 |
3  brn  | 4 | shutter direction
4  red  | 3 | dome direction
42 blk  | gnd |

An ASCOM/Alpaca driver was written to provide remote access to the dome control. The driver needs to 
be started when dome1m is rebooted.

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