See GA drawing IC/000. This holds the multiaperture masks precisely in the focal plane of the telescope (the telescope must be focussed onto the masks as part of the general setup). The latching mechanism also ensures that the displacement of the masks orthogonal to the optical axis is kept very small.
The wheel is moved by a stepper motor driving through a reduction gearbox and a tensioned toothed belt. The wheel hub is fitted with a rotary encoder which provides the local controller with a zeroset pulse. In order to maintain a fixed relationship between the wheel and the encoder, the wheel is dowelled to the hub and the encoder is dowelled to the wheel shaft.
The clamping mechanism consists of a plunger mounted on a linear slide which is driven by a pneumatic cylinder actuated by a solenoid valve. When the valve is not actuated, this drives under spring pressure into a V-block located on the wheel rim at each of the 8 mask positions. Shoes mounted on the other side of the wheel make contact with cam-followers acting on a line with the plunger. Thus the axial position of the wheel is precisely defined. When the solenoid is activated the clamp is lifted out of the V-block allowing the wheel to be moved by the stepper motor. The default position of the plunger, when no power is applied to the solenoid, is such that the wheel is clamped.
The position of the wheel in a tangential direction (i.e. orthogonal to the optical axis) is defined by the V-block. The job of the stepper motor is simply to get the correct V-block into approximately the right position.
The mounting arrangement for the aperture masks is given in Section 4.1.
Each mounting hole is clearly labelled on the outer face of the V-block from 0 to 7. '0' is normally kept clear.
See GA drawing IE/000. This is similar in principle to the aperture wheel but with the following difference.
The wheel contains 8 round apertures, each of which may be mounted with a filter+cell. The positions are clearly labelled near the V-block from 0 to 7. 0 is generally kept as the clear position and positions 1 and 2 are normally kept for Hartmann filters HL and HR. See section 4.2 for details of how to mount the filters.
See GA drawing IF/000. This is similar in principle to the aperture wheel but with the following difference.
The wheel contains 3 square holes for the grisms and 3 round holes for filters. The square holes alternate with the round ones. One of the round holes (labelled '0') is kept for the clear position. The others are labelled (close to the V~block) sequentially from this position. See section 4.3 for details of how to mount the grisms.
See GA drawing IH/000. The camera is mounted in an assembly which allow the position of the camera along the optical axis to be altered by +/-0.4mm. The assembly consists of a movable central section on which the camera is mounted supported by two large linear slides off a section which is fixed securely to the inside of the bottom unit of the structure. A stepper motor driving through a worm gear pushes down on one side of a lever. The other end is attached to the movable part of the focussing assembly and so lifts the camera upwards. A handle may be attached to the shaft running through the stepper motor to allow manual control of the camera position. Springs linking the movable and fixed sections keep the movable section locked against the lever head.
An SLVC (Super Linear Variable Capacitor) is attached to the fixed part of the assembly with the spring-loaded probe head resting against a bracket attached to the movable part. Thus it senses the axial position of the camera. The SLVC has signal conditioner unit which is fixed via an insulating plate to the inside of the bottom unit of the structure. The three leads link the probe to the signal conditioner unit are very delicate and must be handled with care.
HANDLING PRECAUTIONS
Handle the SLVC leads which join the probe to the signal conditioner unit with care. Do not overbend them or subject them to any excessive stress. Do not clamp them in a vice. Do not attempt to modify them.
A spare SLVC probe and signal conditioner unit is provided. The setting of the SLVC probe should not be altered since this will destroy the calibration between the physical position of the camera and the SLVC readout.
TAMPER WARNING
Do not remove the SLVC probe from its mounting bracket unless absolutely necessary. If it is removed, replace it so that the collar butts up against the mounting bracket. Do not remove the collar.
See top unit GA drawing II/001. There are two doors which can be locked and unlocked pneumatically via the control system. Each door has two handles which operate by pulling outwards (like ISIS etc.). Sensors attached to the latching mechanisms (a bar which rotates to insert or withdraw pins from the tongues of the latches) detect when the latching mechanism has operated and another set detect whether the door is actually open or closed. These sensors are Hettisch-type proximity switches. It is necessary to give the doors a good bang after they have been closed to ensure that the latching pins fall into in place and that the door sensors detect that the door has in fact been closed. The doors are lined with gasket material to make them light tight.
The doors are interlocked with the shutter and so will only open if the shutter is closed. The interlock may be overridden using the manual handset.
The doors may be opened manually by removing a small circular cover plate (held on by three tiny screws) at the top of each door. This reveals a hole through which a small bore rod may be pushed (e.g. a small screwdriver shaft). Moderate pressure applied in this way allows the bar connecting the latching mechanism to be rotated so that the latching pins are withdrawn from the tongue of the door latches. This is the only way to open the doors if the power is off.
See GA drawing VX/200. This is a Prontor shutter driven from the shutter control card in the local controller. It is mounted off the grism D-plate. It has two manual control handles. One opens and closes the shutter, the other locks it in the open position. A proximity switch in the shutter unit detects the open/closing of the shutter. Electrical signals go via a military connector mounted on the box which contains the manual controls. It is very difficult to plug this connector in when the grism wheel D-plate is mounted in the bottom structure.
The local controller consists of a 4MS-based computer system, together with a SMDM (Stepper Motor Driver Module) and a number of ancillary circuit boards. it is housed in a 6-U rack, which is placed in one of the electronics cubicles at the cassagrain focus.
Its purpose is to provide an interface between the WHT system computer and the following mechanisms:
The Aperture Wheel
The Filter Wheel
The Grism Wheel
The Focus Mechanism
In addition, facilities are provided for controlling the door locks (normally under the control of the system computer) and the shutter (normally under the control of a CCD or an IPCS controller).
2.1 Parts List
The rack is composed of the following parts:
· 6Ux360 subrack side-panels
· 6U front mounting flanges
· Top-f ront tie bars
· Bottom-front tie bars
· Top-back tie bars
· Bottom-back tie bars
· DIN connector mounting rails (shortened to 1 Ocm approx)
1 Hinged panel
1 Four-hole connector panel (custom)
1 Seven-hole connector panel (custom)
1 Three-hole connector panel (custom)
1 Five-hole connector panel (custom)
26 160mm card guides
4 220mm module guides
2.2 Assembly
The top-front tie bars should be located as follows (holes numbered from the front, working back):
Top row, holes 1 &3, facing forward
Top row, holes 12&14, facing forward
Top row, holes 27&28, facing backward
Lower middle row, holes 1 &3, facing forward
Lower middle row, holes 27&29, facing backward
The top-back tie bars should be located as follows:
Top row, holes 23&23, facing backward
Lower middle row, holes 17&1 9, facing backward
The bottom-front and bottom-back tie bars should be located in the upper-middle and bottom rows, so as to mirror the tie bars in the top and upper-middle rows.
The hinged panel should be attached as the upper front panel. The lower front panel consists of the four-hole connector panel (on the left), the seven-hole connector panel (in the middle) and the power supply module (on the right). The upper back panel is the three-hole connector panel. The lower back panel is the fwe-hole connector panel. It is recommended that none of these be attached until the wiring is complete.
The card guides are placed in the upper half of the rack, and the module guides in the lower half. Each guide has two possible orientations: the slot that takes the card may be on the left or on the right.
Two of the card guides have the slot on the right, and are located as a pair on position 58. The other twenty four have the slot on the left, and =upy'poshions 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40 and 43. The module guides also have the slot on the left, and occupy positions 62 and 82.
The DIN connector mounting rails are fixed onto the top and bottom back tie bards, immediately behind the bottom right of the module guide rails.
3.1 Parts List
1 12-siot G64 bus Backpiane
1 CPU card
1 Bus Buffer Interface card
1 Memory expansion card
1 GPIB Interface card
1 Serial Interface card
1 Analogue/Digftai Converter card
3 Rotary Encoder cards
1 Parallel Interface card
1 Shutter Control card
1 Stepper Motor Driver Module
1 Power supply module
1 1 OOW 22R resistor
3.2 Assembly
The backpiane is attached to the back tie bars in the upper had of the rack, such that the twelve sockets line up with the twelve pairs of card guides. You should then configure the cards, as detailed below. Once this is done, the cards can be inserted in the following order (numbered from the left):
1. GPIB Interface card
2. Serial Interface card
3. (slot vacant)
4. Analogue/Dighal Converter card
5. Rotary encoder card #l
6. Rotary encoder card #2
7. Rotary encoder card #3
8. CPU card
9. Bus Buffer Interface card
10. Memory expansion card
11. Parallel Interface card
12. Shutter Control card
The Stepper Motor Driver Module is held in place by the card guides to the right of the backpiane, while the power supply module is held in the module guides at the bottom right of the rack. The power supply module should not be inserted until the cable harness is in place.
3.3 Card Specification and Configuration
3.3.1 CPU Card
Supplier: Syntel
Designation: SYN MPO9
Crystal: 4MHz
PROM: Map 5
ROM: Forth v2 18-7-87
Links: as supplied
Additional documentation: SYN MPO9 User Manual (part of 4MS System Manual)
3.3.2 Bus Buffer Interface Card
Supplier: RGO Electronics Group
Designation: 4MS-BBI WEM002
Link JL1: connect 6-19,10-37,13-26 (purpose unknown)
Link JL2: connect 1-2 (to enable watchdog timer)
Additional documentation: 4MS-BBI User Manual (part of 4MS System Manual)
3.3.3 Memory Expansion Card
Supplier: RGO Electronics Group
Designation: Unknown
This board can be configured to support either four 8K SRAMs or four 8K EPROMS. An additional SRAM or EPROM is located on the CPU card.
Additional documentation: None
3.3.4 GPIB Interface Card
Supplier: Syntel
Designation: SYN 1488
Switch SW1: set to Off, Off, Off, On, Off, Off (purpose unknown)
Switch SW2: set to Up, Up, Up, Up, Up, Up, Up, Down (purpose unknown)
Additional documentation: SYN 1488 User Manual (part of 4MS System Manual)
3.3.5 Serial Interface Card
Supplier: Syntel
Designation: SYN ACM3 User Manual (part of 4MS System Manual)
Require port I configured as RS422, ports 2 and 3 as RS232
lCs: U15, U17 and U20 present, U14, U18 and U21 absent
Link Jl: connect 1-2, 3-4, 5-6, 7-8, 9-17-19,13-14,15-16 (port 1 RS422)
Link J2: connect 1-2, 5-6, 9-10, 13-14, 17-18-21-22 (port 2.RS232)
Link J3: connect 1-2, 5-6, 9-10, 13-14, 17-18-21-22 (port 3=RS232)
Link J4: connect 2-3-4-5 (port 1-RS422)
Link JS: connect 1-2-3-4-5 (port 2=RS232)
Link J6: connect 1-2-3-4-5 (port 3.RS232)
Link J7: no connection (purpose unknown)
Link J8: no connection (purpose unknown)
Link J9: no connection (purpose unknown)
Link J 1 0: conned 2-3 (purpose unknown)
Link Jl 1: conned 2-3 (purpose unknown)
Link J12: conned 2-3 (purpose unknown)
Link Jl 3: connect 1-3-4-5 (purpose unknown)
Dil switch: set to On, On, On, On, On, On (to set base address to DCOO)
Additional documentation: SYN ACM3 User Manual (part of 4MS System Manual)
3.3.6 Analogue/Digital Converter Card
Supplier: Syntel
Designation: SYN ADC2
Link Jl: connect 1-3 (select 0-1 OV input range)
Link J2: connect 1 -2, 3-4 (select 0-1 OV input range)
Link J3: undefined (not used, purpose unknown)
Link J4: undefined (not used, purpose unknown)
Link J5: connect 1-2 (purpose unknown)
Unlabelled link: no connection (purpose unknown)
Dil switch: set to Off, Off, On, Off, On, On (set to base address DC70)
Additional documentation: SYN ADC2 User Manual
3.3.7 Rotary Encoder Card #l
Supplier: Gespac
Designation: GESINC-1
Link Jl: connect 1-2 (enable protective ground)
Link J2: connect 2-3, 4-5 (se@ power from backpiane)
Link J3: connect 2-3, 4-5 (se@ power from backplana)
Link J4: connect 1-12, 3-10, 5-8 (select single-ended inputs)
Link J5: conned 1-2 (select phase A active high)
Link J6: connect 1-2, 4-5 (select phase B and TOPO active high)
Link J7: no connection (disable interrupts)
Link J8: connect pairs 1, 2, 3, 5, 6 and 7 (set to base address DC40)
Additional Documentation: GESINC-1 data sheet
3.3.8 Rotary Encoder Card #2
As above, except
Link J8: connect pairs 1, 2, 3, 5, 7 (set to base address DC50)
3.3.9 Rotary Encoder Card #3
As above, except
Link Jg: connect pairs 1, 2, 3, 6, 7 (set to base address DC60)
3.3.1 0 Parallel Interface Card
Supplier: Gespac
Designation: GESPIA-2A
Link Jl: connect 1-6 (makes +5V present on output connectors)
Link J2: no connection (disables watchdog)
Link J3: no connection (disables watchdog interrupts)
Link J4: no connection (disables PIAO interrupts)
Link JS: no connection (disables PIA1 interrupts)
Link J6: connect 1-1 4, 4-11, 5-10, 6-9, 7-8 (set to base address DC30)
Additional documentation: GESPIA-2A data sheet
3.3.1 1 Shutter control card
Supplier: Durham University
Designation: none
Link Jl: no connection (no pull-up on reset line when connected to backplane)
Additional documentation: Shutter Control Card User Manual
(includes circuit diagram, board layout, PCB mask and parts list)
3.4 Module Specification
3.4.1 Stepper Motor Driver Module
Supplier: Royal Greenwich Observatory
Designation: SMDM
3.4.2 Power supply module
Supplier: Durham University
Designation: none
This module contains two separate power supplies: one to provide +SV, +12V and 12V to the 4MS system, and one toprovideanadditionai+15Vand 15VforthoSLVCsignalconditioner.
Its current ratings are: 8A Cffi 5V, 3.5A i@ 12V
Connection to the rack is by means of an 'H'-type connector (RS 481-960), with pins as follows (numbered from the top of the module):
1 Earth
· 24OV Neutral
3 24OV Live
4 ov
· ov
· +5V
· +5V
· +12V
· 12V
1 0 +15V
1 1 15V
12 NIC
1 3 NIC
1 4 N/C
1 5 N/C
The OV line is internally referenced to earth via a 10OR resistor. There have been some problems with the +SV supply on the backpiane being too low. These were dealt with by (a) using multiple pins connected in parallel on the OV and +5V lines and (b) by adjusting the power supply so that ft actually generates between +5.1 OV and +5.15V. By the time this reaches the backpiane, ft should be around +4.9V under full load, but h is still well within the TTL supply range under no load. A better solution d the controller were ever upgraded would be to use a power supply with a sense line.
The front panel of the power supply module has five LEDS, one for each power line. The upper row corresponds to the positive rails, the lower row to the negative ones. 5V is red, 12V is green, 15V is orange. There is a rotary switch to disable the LEDs during observation to minimise scattered light.
Internally, the power supply module consists of a Verospeed XL80-4601, which supplies ±5V and ±12V (the 5V signal is not used), together with a simple dual-rail linear supply to provide ±15V. The OV lines of these two supplies are connected together. The pinouts of the XL80-4601 are (looking at the edge of the board, left to right):
3-way Moiex:
I 24OV Live
· 24OV Neutral
3 Earth
12-way Moiex:
1 5V
· 12V
· +12V
· +12V
· ov
· ov
· ov
· ov
· +5V
10 +5V
1 1 +5V
12 +5V
The pinouts for the custom ±15V supply are (looking at the relevent edge of the board with the transformer on the upper side of the card, from left to right):
3-way Terminal Plug:
1 24OV Live
· 24OV Neutral
3 Earth
4-way Terminal Plug:
1 ov
· N/C
· isv
· +lsv
The internal connections to the switch are as follows (looking at back of switch, numbering from top left to bottom left to bottom right):
1 N/C
· Common (OV)
3 Switched OV #l
4 Swftched OV #2
· Common (OV)
6 N/C
Finally, the connections to the LED circuhboard attached to the front panel are (looking at the back of the board, numbering from left to right):
3-way Molex:
1 OV (Swftched)
2 12V
3 15V
5-way Molex:
1 OV (Switched)
· +12V
· +5V
· +15V
· N/C
3.4.3 1 OOW 22R Resistor #l
This is mounted in the middle of the lower had of the left hand side panel (behind the military connectors on the front panel). It is connected to the shutter control card, and is used to limit the heat dissipation in the shutter solenoid.
3.4.4 1 OOW 1 OR Resistor #2
This is also mounted in the middle of the lower had of the left hand side panel. It is connected between the +1 2V and OV power supply lines on the backpiane, and is used to ensure that the power supply operates within spec. (The power supply must be loaded to at least 25% capacity on both the +1 2V and +5V lines. In the case of the +1 2V line, this means 25% of 3.5A).
3.4.5 Manual Control Handset
This is connected to the front panel of the local controller via a 6-way Lemo plug/socket.
The following functions are provided by SPST rocker switches: Open Shutter, Open Door.
The following functions are provided by SPST rotary switches: Shutter Interlock Override, Wheel Interlock Override.
4. Power Supply Wiring and Earthing
The following colour codes used throughout the local controller:
Earth: Yellow/Green
24OV Live: Red or Brown
24OV Neutral: Black or Blue
+24V: Red or Brown
24V: Black or Blue
All cable screens are connected to the chassis, as is the 4MS itself. At the time of writing, the chassis is connected to mains earth, but this may not be a desirable operational configuration.
LDSS-2 Local Controller
Software Description
Revision 1
@ 28th February 1992 Graham Shaw
1. Introduction
This document describes the LDSS-2 local controller software.
2. Diagnostic Words
The following diagnostic words are available:
SIGN-ON Purpose unknown
NET101 Purpose unknown
M-LIST Display contents of monftor-mode list
S-LIST Purpose unknown
WHO Purpose unknown
TRANSPARENT Communicate directly with SMDM associated with mech on TOS
TT Shorthand for TRANSPARENT
.SLINKS Display status of SMDM serial link and of air pressure
#LINK Purpose unknown
LLL Shorthand for #LINK
KKK Purpose unknown
.TIMEOUTS Display number of comms timeouts since last reset
SEE Display prosentstatus table for mechanism number on TOS
.MECHS Purpose unknown
#SLINK Purpose unknown
LOCAL Enter command as d ft had been received over the ethernot
I (Pipe) Shorthand for local
Where these words require a mechanism number on top of stack, the following mnenomics may be used:
APW Aperure wheel (0)
FLW Filter wheel (1)
GRW Grism wheel (2)
FOC Focus (3)
DOR Doors (4)
scc Shutter Control Card (5)
With the exception of SLINKS, the above diagnostic commands behave in the same manner as existing RGO 4MS software. The behavior of TRANSPARENT is as for a standard SMDM.
3. Mechanism Summary
LDSS-2 has six mechanisms, as enumerated in the proceeding section. There are also six pseudo-mechanisms: INS, MON, HMS, ALL, RES and NET. These are not documented here, as they are as for existing RGO 4MS software.
3.1 APW (Aperture Wheel)
Commands:
APW101(n) Move wheel to position n (between 0 and 7)
APW102 Initialise mechanism
APW1 81 Reprogram SMDM
APW182 Initialise from arbftary position
APW1 83(n) Clamp wheel (n-O) or unciamp wheel (n-l)
(Note: APW1 02 is the normal initialisation command, but k only works K the wheel begins from a clamped position. APW182 can be used to initialise from any position, but should only be used while the telescope is at zenith. The APW1 00 command (Stop) is implemented, but should not be used as K could cause damage to the mechanism.)
Return values as for existing RGO software, but note:
position Range 0..7, or 1 if in transit between two positions
Stepcount Range 0..31 999
Datum Sw. Bft-0 true K clamped, bft-l true if unciamped
New mechanism error codes (hex):
13 Failed to clamp wheel
14 Failed to unciamp wheel
16 Failed due to wheevdoor interlock
10 Failed due to wheevair pressure interlock
Interlocks:
The wheels will not move unless the doors are both closed and locked. This interlock can be overridden using the manual control handset.
3.2 FLW (Filter Wheel)
Commands:
FLW1 01 (n) Move wheel to position n (between 0 and 7)
FLW102 Initialise mechanism
FLW1 81 Reprogram SMDM
FLW1 82 Initialise from arbkary position
FLW1 83(n) Clamp wheel (n-O) or unciamp wheel (n-l)
(Note: FLW1 02 is the normal initialisation command, but K only works if the wheel begins from a clamped position. FLW1 82 can be used to initialise from any position, but should only be used while the telescope is at zenkh. The FLW1 00 command (Stop) is implemented, but should not be used as it could cause damage to the mechanism.)
Return values as for existing RGO software, but note:
Position Range 0..7, or 1 if in transit between two positions
Stepcount Range 0..31 999
Datum Sw. Bft-O true d clamped, bft-l true if unciamped
New mechanism error codes (hex):
13 Failed to clamp wheel
14 Failed to unciamp wheel
16 Failed due to wheevdoor interlock
10 Failed due to wheevair pressure interlock
Interlocks:
The wheels will not move unless the doors are both closed and locked. This interlock can be overridden using the manual control handset.
3.3 GRW (Grism Wheel)
Commands:
GRW1 01 (n) Move wheel to position n (between 0 and 5)
GRW102 Initialise mechanism
G RW1 81 Reprogram SMDM
GRW1 82 Initialise from arbkary position
GRW183(n) Clamp wheel (n-O) or unciamp wheel (n-l)
(Note: GRW1 02 is the normal initialisation command, but h only works R the wheel begins from a clamped position. GRW1 82 can be used to initialise from any position, but should only be used while the telescope is at zenfth. The GRW1 00 command (Stop) is implemented, but should not be used as ft could cause damage to the mechanism.)
Return values as for existing RGO software, but note:
Poskion Range 0..5, or 1 d in transit between two positions
Stepcount Range 0..31 999
Datum Sw. Bft-O true d clamped, bft-l true if unciamped
New mechanism error codes (hex):
13 Failed to clamp wheel
14 Failed to unciamp wheel
16 Failed due to wheevdoor interlock
10 Failed due to wheevair pressure interlock
Interlocks:
The wheels will not move unless the doors are both closed and locked. This interlock can be overridden using the manual control handset.
3.4 FOC (Camera Focus)
Commands:
FOC1 00 Stop Mechanism
FOC101(n) Move focus to position n (between 0 and 767 microns)
FOC 1 02 Initial!" mechanism
FOC1 81 Reprogram SMDM
Return values as for existing RGO software, but note:
Posftion Range 0..767 microns
Stepoount Range 0..5000
New mechanism error codes (hex):
1 E Failed due to SLVC/Focus Interlock
Interlocks:
The focus will not move unless the position sensor is connected to the ADC board. This is to prevent the mechanism
from attempting to servo when there is no feedback.
3.5 DOR (Access Doors)
Commands:
DOR1 01 (n) Unlock doom (n-O) or lock doors (n-l)
DOR102 Initialise mechanism
Return values:
Posftion Indicates current status of the two doors: Bft Of also -door 1 locked Bft 1 false - door 1 closed Bft 2 false - door 2 locked Bft 3 false - door 2 closed
Datum Sw. Duplicate of Position field
New mechanism error codes (hex):
15 Failed due to shutterldoor interlock
17 Door 1 failed to lock
1 8 Door 2 failed to lock
1 9 Door 1 cannot be locked as it is open
1A Door 2 cannot be locked as it is open
1 B Door 1 failed to unlock
1 c Door 2 failed to unlock
Interlocks:
The doors cannot be unlocked while the shutter is open.
3.6 SCC (Shutter Control Card)
Commands:
None
(Note: this mnemonic exists only to allow status information to be returned from the shutter con trol card to the 4MS system. ft does not therefore have any valid commands associated with ft.)
Return values:
Stepcount Contains latest status information read from shutter control card. See network interface documentation for full details.
Interlocks:
The IPCS and CCD controllers cannot open the shutter unless the doors are closed and locked. The failure of an operation as a result of this interlock can be detected by monitoring the SCC stepcount field.
Release Notes for LDSS-2 4MS Software Vl.2:
1) Correction to grism wheel status maintain task. Previously, it was possible for the wheel to appear to be in position 6, even though it only had positions@0..S. Fixed.
2) New command and abbreviations for existing commands:
INTERLOCK STATUS (Abbreviation ILS)
(Display the status of the sensors likely to cause an interlock, together with the two hardware interlock-overrides (the door/shutter interlock and the door/wheel interlock) and the two software interlock overrides (the air pressure interlock and the focus/SLVC interlock).
AIR - ILOCK-VRIDE-ENABLE (Abbreviation E-AIR)
(Enable interlock between wheel mechanisms and air pressure switch.)
AIR-ILOCK-VRIDE-DISABLE (Abbreviation D - AIR)
(Disable interlock between wheel mechanisms and air pressure switch.)
FOC - ILOCK - VRIDE-ENABLE (Abbreviation E-FOC)
(Enable interlock between SLVC/ADC and focus mechanism).
FOC-ILOCK-VRIDE-DISABLE (Abbreviation D-FOC) (Disable interlock between SLVC/ADC and focus mechanism).
WHT-LDSS1 Vl-6
3.3 Mechanism Error Status Values
0116 NTIMEOUT Mechanism timeout.
0216 CTIMEOUT Communications timeout.
0316 UNDEFPOS Undefined position.
0416 UNZEROED Not zeroset.
0516 MODERROR Module name is incorrect.
0616 IIVLDATA Invalid data returned.
0816 ABORTED Pending operation aborted.
Erro.rs associated with SMDM operations
0C16 SXDMBUSY SMDM Module Busy.
0016 SKDMOUTR SMDM Out-of-range value.
0E16 SMDMINVN SMDM Invalid Motor number (Not in range 1-4).
OF16 SNDMNOTI SMDM Motor not initialised.
1016 S)(DMLZER SMDM LIMIT set to zero.
1116 SMDMLIMI SMDM Limit switch activated.
1216 SNDMNSCM SMDM Not set to cycle mode.
Errors specific to LDSS mechanisms
1316 CLMPFAIL Failed to clamp.
1416 UNCLFAIL Failed to unclamp.
1516 SHUILOCK Operation prevented due to shutter interlock.
16,r, DORILOCK Operation prevented due to door interlock.
1716 DILKFAIL Door 1 lock failure.
1816 D2LKFAIL Door 2 lock failure.
1916 DILKOPEN Door 1 failed to lock door open.
1A16 D2LKOPEN Door 2 failed to lock door open.
1B16 D1ULFAIL Door 1 unlocking failure.
1C16 D2ULFAIL Door 2 unlocking failure.
1D16 AIRULDCK Operation prevented due to air pressure low.
1E16 FOCENCNC Focus transducer not connected.
2016 SHSERROR Shutter status error (details in step-count).
Particularly pertinent error symbols are given with each message definition.
4
1. Introduction
This document described the local controller software for LDSS-2. The software in question is written in FORTH, and runs on a 6809-based 4MS system.
LDSS-2 has six mechanisms under the control of or monitored by the 4MS:
The Aperture Wheel
The Filter Wheel
The Grism Wheel
The Camera Focus
The Doors
The Shutter
2. Mechanism Descriptions
2.1 Aperture Wheel
The aperture wheel consists of a carosel with eight holes in ft. It is controlled by a stepper motor (driven by an SMDM). The wheel is monitored by an incremental rotary encoder, and when stationary is held in position by means of a clamp. The clamp is operated pneumatically by means of a solenoid valve, and sensors exist to detect whether it is in the clamped or unciamped position.
2.2 Filter Wheel
For the purposes of the software, the filter wheel is identical to the aperture wheel.
2.3 Grism Wheel
For the purposes of the software, the grism wheel is identical to the aperture wheel, except that ft has 6 holes.
2.4 Camera Focus
The camera focus can be driven over a range of approximately 750um by a stepper motor (driven by an SMDM), via a lead screw. The focus position is monitored by an SLVC (super-linear variable capacitor).
2.5 Doors
LDSS-2 has two access doors, which must be closed and locked during exposures, but which may need to be opened from timeto time in order to change aperture masks, filters etc. They are opened/closed manually, but locked/unlocked pneumatically. A single solenoid valve controls both door locks. Each door has sensors to indicate whether the door is locked, and whether h is locked. Note that it is possible for the lock to be in the locked position even though the door is in fact open.
2.6 Shutter
The shutter is not controlled by the 4MS, but instead by the CCD or IPCS controller as appropriate. All decisions relating to the shutter are taken by the hardware, but the 4MS does play a role in monitoring this process.
3. Software Start-up Sequence
The 4MS control software can be loaded from disc by issuing the following commands:
9 LOAD 76 LOAD 77 LOAD
In normal operation, the software would be programmed into EPROM, in which case R should start automatically.
4. Memory Map
The 110 address map is as follows:
DCOO Serial Comms Card (ACM-3)
DC30 PIA Card (GESPIA-2A)
DC40 Incremental Encoder Card #3 (GESINC-1)
DC50 Incremental Encoder Card #2 (GESINC-1)
DC60 Incremental Encoder Card #l (GESINC-1)
DC70 ADC Card (Syntel ADC3)
Please refer to the relevent data sheet for descriptions of individual registers.