3. Hardware Description.

3.1. Boards in the VME rack.

1. Ironics system controller with SCSI port connected to three disks:

- a 70 Mbyte Quantum disc containing the Application software and Dark Current images.

- a 10 Mbyte Kodak "Take Ten" Removable disk used for backups.

- a 21 Mbyte Insite Floptical drive which will take 3.5"floppy discs and 3.5" floptical discs, also for backups and software releases.

2. a VMPU module containing a 68020 processor and local memory.

3. An Opal Colour Graphics controller card supporting 4 pages of 800x600 pixels. The Autoguider display only uses one page.

4. A 2 Mbyte Ram Module currently starting at hex 4000000

5. A second 2 Mbyte Ram Module starting at hex 6000000

6. a DICI interface module, which connects to the FOX chassis to receive Image data from the CCDc.

7. A Four Port Serial Interface card for the serial lines to the TCS, and the CCD controllers at each of the three focal stations.

SP1 - TCS vax link for error signals

SP2 - Cassegrain ccd controller link

SP3 - UES ccd controller link

SP4 - Prime ccd controlller link.

3.2. Notes on the VME rack setup.

The Opal and DICI cards have connectors on the reverse of the VME bus and thus need to be plugged into the same slots each time. Interrupts are daisy chained along the backplane so all of the cards have to be contiguous. The exception is the VMPU card which takes up two slots due to the size of the heatsink on the CPU. There are links on the backplane to connect the interrupts to the next door cards, so the CPU card must not be move either. Given these constraints, the rest of the cards can be plugged in in any order. The order of the cards defines interrupt priorities so it is advisable to leave things alone.

3.2.1. Connections to the rest of the system

3.2.2. Fibre optic connections.

The FOX chassis multiplexes data from several sources onto a bus which the DICI card reads. The cards may be in any order, though it is recommended that they are in the order of Cassegrain, UES, Prime, and AutoFib, reading from left to right. All the fibres should be left installed at, though the system can cope with a fibre missing if that focal station is not in use.

3.2.3. Serial lines.

This version of the Autoguider software is designed to switch between the different serial ports connected to the CCD controllers. The ports are arranged as shown in the table below.

SP1           TCS link                                
SP2           Cassegrain  controller                  
SP3           UES CCD controller                      
SP4           Prime focus CCD controller              

Table 3. Serial link port allocations

3.2.4. Display.

The Autoguider display is connected to the VME rack via three BNC cables which are connected to the assembly at the rear of the rack. They go to the respective connections on the back of the display and should be terminated into 75W.

3.2.5. Mouse.

There is no mouse supported in this version of the Autoguider .

3.3. CCD controllers

The serial interface driver which controls the ports connected to the CCD controllers waits for either a Forth ok or ? >> response from the CCD controller after issuing each command. There is a timeout mechanism which allows the Autoguider software to continue, albeit with difficulty, should the CCD controller hang up or not be connected. One serial port has been assigned to each of the controllers on the telescope, and these are expected to be left connected. On loading the serial interface handler and CCD controller interface code, each port is probed for the presence of a ccd controller. A TTY command is issued to the controller, and if an ok response is issued within 0.5 seconds, then the controller is deemed to be connected. A database of connected controllers is maintained. If a controller is not connected ( ie the TTY timed out ) then no data is sent to the port so that the software may continue to the point where an error can be reported to the user or network. The only difference in operation between one controller and another is the port where the commands are sent. Differences in interpretation of the image and parameters are controller higher up.