The Mirror 3 electronic unit controls the shifting of the observation service to the right hand or left hand platform of the telescope by rotating the Nasmyth system 180 degrees. It also allows the control of the M1 Sliding Cover, the M3 Baffle and the shutters on Focus A and B of the telescope.
The rotation of the Nasmyth system is effected by a torque motor. The two final positions are approached via an incremental encoder and fixed by an electro-magnetic brake.
The time taken for rotation from one focus to the other is between 30 and 60 seconds. Absolute reproducibility is 2,5 seconds of arc.
The M1 cover slides on the center piece of the telescope above the M1 and the Nasmyth mirrors. Its motion is effected by a 3-phase motor. The final positions are detected by mechanical end-switches.
The M3 Baffle slides up and down along the altitude axis of the telescope above Mirror 3. One on-off dc motor moves the M3 Baffle system. The two final positions are detected by two proximity sensors.
The two shutters on Focus A and B control the passage of the light into the adapters of the telescope. Their functions are carried out by the rotation of one on-off dc motor. The two final positions are detected by proximity sensors.
The four main functions carried out in the Mirror 3 electronic unit are under the control of a local unit. The local control unit includes two cabinets (M3-1 and M3-2) mounted on the center piece of the telescope; the M3 VME system is in the M3-1 cabinet.
The rotation of 180 degrees is effected by a torque motor controlled in torque, velocity and position in a proportional integral-type servo loop system. An incremental encoder delivers the actual position during rotation of the Nasmyth structure. The two final positions are reached by reading out the expected data from the incremental encoder counter card.
The zero pulse of the incremental counter is used during initialization as an absolute position referred to the mirror position. Location at the final positions is effected by means of an electro-magnetic clutch. A vertical position interlock disables the shifting of the observation platform when the tube of the telescope is not close to the zenith position.
The sliding cover can be closed or opened by means of an ac 3-phase motor and a mechanical two-drive system. Only the two final positions of the cover can be obtained through the remote mode. Intermediate positions are performed by means of special functions (local or test mode). Mechanical limit switches disable the command circuit at end positions.
M1 cover motion is interlocked with the M3 Baffle.
The baffle can be moved up and down by means of an on-off dc motor, a pinion and spindle drive system. The remote mode allows the upper and lower positions of the baffle. Intermediate positions can be obtained by special functions implemented in the electronic control module (local or test mode). Inductive proximity sensors disable the command circuit at final positions. A brake fixes the final positions reached.
An interlock based on electronic hardware disables the command circuit of the baffle when limit switches indicate that the M1 Sliding Cover is closed or is not completely opened.
Another interactive interlock disables the command circuit of the M1 cover when the baffle lower inductive switch is not activated. In manual or test operations, intermediate positions of cover and baffle both totally block computer control of these two functions. To cure this problem of interactive interlock, it is necessary to initialize the two systems to their end limits in manual or test mode.
The mechanical system for shuttering the focuses consists of two discs of electrically and magnetically isolated material with an eccentric circular hole in each disc. The two discs rotate in opposite directions via pinion drives. Two magnetic marks are mounted on the isolated discs in such a way that when one mark is detected by an inductive sensor, the shutter is closed. If both marks are detected, the shutter lets the light go through the adapter of the telescope.
Default Settings
Operating Sequence
| INPUTS | NORMAL STATUS | IF NOT, CHECK ... |
| PAFAULTI* | Negated | Inland power amplifier |
| IEERRI* | Negated | Heidenhain EXE 702B |
| PACURI | Analog data 0V | Inland power amplifier |
| ILVPOSI* | Asserted | Telescope is more than 15 degrees further from zenith position, vertical position interlock module (M3-2 cabinet) |
| VANGLI | Analog data 2,5V +/- 0,1V | Software vertical position of the tube, vertical position interlock module (M3-2 cabinet) |
| M3-1 TEMP40I* | Negated | Temperature in M3-1 cabinet higher than 40 degrees C |
| M3-2 TEMP30I* | Negated | Temperature in M3-2 cabinet higher than 30 degrees C |
| ILEMSTO1I | Negated | Emergency Stop push-button EMSTO1I is not released |
| ILEMSTO2I | Negated | Emergency Stop push-button EMSTO2I is not released |
Reading Out The Encoder
The Heidenhain encoder is an incremental type having a resolution
of 0,02 degrees or 72 arc second (18000 lines per revolution).
The Heidenhain Evaluation and Interpolation Electronic EXE 702B
increases the resolution by a factor of 25; i.e. 0,0008 deg or
2,88 arc sec.
The ESO Incremental Encoder Counter Card multiplies by 4 again;
the global electronic resolution is then 0,0002 deg or 0,72 arc
sec. Tolerance is 2,5 arc sec/ 0,72 arc sec = +/- 3,5 counting
pulses.
Initialization
After initialization of the incremental encoder counter card through
the command IERESET*, the Nasmyth mirror rotates until it finds
an absolute position that is defined by the detected zero pulse
ZP from the encoder.
The flag IEZERO* indicates that the zero pulse position has been
registered and must be the first read out. The relative position
from the zero pulse can be read at any time through the command
IECS*.
Activation of IECS* registers the current counter data and it
must stay active until the end of the read out sequence; transfer
of 4*8 bits counter value.
IEDREADY*, handshake to local VME, indicates that the 8 bits counter
value is available.
After receiving IEBREAD* from the local VME, the incremental encoder
counter sends a new handshake IEDREADY* indicating the next byte
is available. At the read out of the last byte, the command IECS*
is de-activated and initialized for the next data position transfer.
Shift From One Focus to the Other Focus
When the absolute position is known (initialization done), the
rotation of the Nasmyth mirror is controlled by reading out the
actual position through the incremental encoder counter card.
Default Settings
Operating Sequence
Default Settings
Operating Sequence
Default Settings
Operating Sequence
Nasmyth Mirror Velocity Loop Adjustment
In order to adjust the velocity loop, a velocity reference input
is implemented in the electronic module vertical position interlock
of the M3-2 cabinet. This allows adjustment of the velocity step
response using an external function generator connected to VREFin
when the system is in TEST mode.
M1 Cover
In parallel with the remote control through the local VME unit,
intermediate positions of the M1 sliding cover can be obtained
for test or maintenance purposes through manual control. This
function is implemented on the M1 cover control module in the
M3-2 cabinet. No interaction with the remote or manual control
mode is possible as, when manual mode is not active, the system
automatically remains in remote mode.
M3 Baffle
For local test and maintenance purposes, manual control of the
M3 baffle is implemented on the M3 baffle control module in the
M3-2 cabinet. Remote mode is always active if manual mode is not
selected.
Shutters on Focus A and Focus B
Manual control of the shutters is possible through the electronic
module M3 shutter control installed in the M3 VME chassis (M3-1
cabinet).
Vertical Position Interlock
This function is mainly implemented in the module vertical position
interlock (M3-2 cabinet) in order to retrieve stored information
of the telescope position independently of the vertical position
provided by the altitude control system. The detection of an angle
more than 15 degrees from the zenith directly disables the Nasmyth
mirror control. The accuracy of this detection is directly linked
to the accuracy of the mercury tilt switch and its mounting support.
An inclinometer is also mounted in the vertical position interlock
module to interlock the Nasmyth mirror control through a software
limit that has an angle from zenith less than 15 degrees.
The signals in the Mirror 3 subsystem are divided into the following
groups that indicate where the signals originate (inputs to the
computer), or where they have to be routed (outputs from the computer).
The above abbreviations are used as the second prefix after the
standard M3 prefix for all Mirror 3 signals.
Note that the SC signals are included in this chapter as the M1
sliding cover is controlled by the M3 computer.
No limit switches assigned to Mirror 3. Refer to Subsections 10.4.6
and 10.4.7 for sliding cover and baffle limit signals.
All sliding cover signals are described in this subsection including
the motor, limit switch and interlock signals. When a limit switch
is activated, it is possible to move in the opposite direction,
so an over-ride signal is not used.
All M3 baffle signals are described in this subsection including
the motor, limit switch and interlock signals. When a limit switch
is activated, it is possible to move in the opposite direction,
so an over-ride signal is not used.
10.3.2 M1 Cover
INPUTS NORMAL STATUS IF NOT, CHECK …
SCLSCLI* Asserted (M1 Cover closed) Telemecanique end-stop, M1 cover card
SCLSOPI* Asserted (M1 Cover opened) Telemecanique end-stop, M1 cover card
SCMTPROTI Asserted Sliding cover motor protection
BALSDNI* Negated M3 baffle is not at lower position
BALSUPI* Negated M3 baffle is at upper position
ILEMSTO1I Negated Emergency Stop push-button EMSTO1I
ILEMSTO2I Negated Emergency Stop push-button EMSTO2I
10.3.3 M3 Baffle
INPUTS NORMAL STATUS IF NOT, CHECK …
BALSUPI* Asserted (baffle up) Baumer sensor, M3 baffle card
BALSDNI* Asserted (baffle down) Baumer sensor, M3 baffle card
SCLSOPI* Asserted (cover opened) M1 cover is not completely opened
SCLSCLI* Asserted (cover closed) M1 cover is closed
ILEMSTO1I Negated Emergency Stop push-button EMSTO1I
ILEMSTO2I Negated Emergency Stop push-button EMSTO2I
10.3.4 Shutters
on Focus A and B
INPUTS NORMAL STATUS IF NOT, CHECK …
ILEMSTO1I Negated Emergency Stop push-button EMSTO1I
ILEMSTO2I Negated Emergency Stop push-button EMSTO2I
10.3.5 Special Functions
10.4 SIGNAL DESCRIPTIONS
10.4.1 Power Amplifier
Signals
NAME TYPE DESCRIPTION PACURI AI*12 Power amplifier current to motor
PAVREFO AO*12 Velocity reference
PAFAULTI* DI*1 PA fault indicator
PAENABLEO* DO*1 Power amplifier enable (Note: disengage brake with MTBRAKE*)
PAON70VO DO*1 Switch on 70V to amplifier
10.4.2 Motor Signals
NAME TYPE DESCRIPTION MTBRAKEO* DO*1 Motor brake disengage
10.4.3 Incremental
Encoder Signals
NAME TYPE DESCRIPTION IEDCH-DI DI*8 Data channel IEDREADYI* DI*1 Data ready handshake from incremental counter
IEBREADO* DO*1 Data read handshake to incremental counter
IEZEROI* DI*1 Zero pulse detected
IERESETO* DO*1 Reset incremental counter
IECSO DO*1 Channel select, latches instantaneous value
IEUPO* DO*1 Up count pulse to incremental counter (test only)
IEDNO* DO*1 Down count pulse to incremental counter (test only)
IEERRI* DI*1 Incremental encoder pulse shaping electronics error
10.4.4 Limit Switch
Signals
10.4.5 Interlock Signals
NAME TYPE DESCRIPTION ILEMSTO1I DI*1 Emergency stop button M3-1 pressed
ILEMSTO2I DI*1 Emergency stop push-button M3-2 pressed
ILVPOSI* DI*1 Telescope in vertical position, M3 rotation is possible
10.4.6 Sliding Cover
Signals
NAME TYPE DESCRIPTION SCOPENO* DO*1 Open sliding cover
SCCLOSEO* DO*1 Close sliding cover
SCMTPROTI DI*1 Sliding cover motor thermal protection, motor switched off
SCLSCLI* DI*1 Sliding cover limit switch closed
SCLSOPI* DI*1 Sliding cover limit switch opened
10.4.7 Baffle Signals
NAME TYPE DESCRIPTION BAUPO* DO*1 Move M3 baffle up BADNO* DO*1 Move M3 baffle down BALSUPI* DI*1 M3 baffle limit switch up
BALSDNI* DI*1 M3 baffle limit switch down
BABRAKEO* DO*1 M3 baffle brake disengage
BAPWONO* DO*1 M3 baffle power on
10.4.8 Shutter Signals
NAME TYPE DESCRIPTION SHUTAOPO* DO*1 Shutter A open command
SHUTACLO* DO*1 Shutter A close command
SHUTBOPO* DO*1 Shutter B open command
SHUTBCLO* DO*1 Shutter B close command
SHALS1I* DI*1 Shutter A limit switch 1
SHALS2I* DI*1 Shutter A limit switch 2
SHBLS1I* DI*1 Shutter B limit switch 1
SHBLS2I* DI*1 Shutter B limit switch 2
10.4.9 Miscellaneous
Signals
NAME TYPE DESCRIPTION M3-1TEMP40I* DI*1 M3-1 cabinet over-temperature, 40 deg. C
M3-2TEMP30I* DI*1 M3-2 cabinet over-temperature, 30 deg. C
VANGLI AI*12 M3 vertical angle
10.5 CONNECTION SCHEDULE
SIGNAL BOARD BIT BIT SIZE
TERMINAL STRIP ACRO PIN ACTIVE LEVEL
DESCRIPTION spare
FFLONO /acro0 1 1 MTS1-13
B31 LOW flat field lamp on SCOPENO /acro0 2 1 MTS1-11
B30 LOW open M1 sliding cover SCCLOSEO /acro0 3 1 MTS1-9
B29 LOW close M1 sliding cover BAPWONO /acro0 4 1 MTS1-7
B28 LOW baffle power on BADNO /acro0 5 1 MTS1-5
B27 LOW move baffle down BAUPO /acro0 6 1 MTS1-3
B26 LOW move baffle up BABRAKEO /acro0 7 1 MTS1-1
B25 LOW disengage baffle brake spare 8
TEMP40I /acro0 9 1 MTS1-29
B23 LOW over-temperature M3-1 cabinet
ILEMSTO1I /acro0 10 1 MTS1-27
B22 HIGH emergency stop push-button 1
TEMP30I /acro0 11 1 MTS1-25
B21 LOW over-temperature M3-2 cabinet
ILEMSTO2I /acro0 12 1 MTS1-23
B20 HIGH emergency stop push-button 2
ILVPOSI /acro0 13 1 MTS1-21
B19 LOW telescope vertical BALSDNI /acro0 14 1 MTS1-19
B18 LOW baffle limit switch down
BALSUPI /acro0 15 1 MTS1-17
B17 LOW baffle limit switch up
SHUTBCLO /acro0 16 1 MTS1-47
A32 LOW close nasmyth B shutter
SHUTBOPO /acro0 17 1 MTS1-45
A31 LOW open nasmyth B shutter SHUTACLO /acro0 18 1 MTS1-43
A30 LOW close nasmyth A shutter
SHUTAOPO /acro0 19 1 MTS1-41
A29 LOW open nasmyth A shutter spare 20
spare 21
spare 22
spare 23
spare 24
spare 25
spare 26
spare 27
spare 28
spare 29
spare 30
spare 31
SIGNAL BOARD BIT BIT SIZE
TERMINAL STRIP ACRO PIN ACTIVE LEVEL
DESCRIPTION PAENABLEO /acro0 32 1 MTS2-40
C32 LOW enable mirror 3 power amplifier
IECSO /acro0 33 1 wire-wrap
C31 LOW incremental encoder channel select
IEBREADO /acro0 34 1 wire-wrap
C30 LOW incremental encoder data read handshake
IERESETO /acro0 35 1 wire-wrap
C29 LOW reset incremental encoder
PAON70VO /acro0 36 1 MTS2-32
C28 LOW mirror 3 power amplifier power on
MTBRAKEO /acro0 37 1 MTS2-30
C27 LOW disengage mirror 3 brake
spare 38
spare 39
spare 40
IEERRI /acro0 41 1 MTS2-54
C23 LOW incremental encoder error
SCMTPROTI /acro0 42 1 MTS2-52
C22 HIGH M1 sliding cover motor protection
SCLSOPI /acro0 43 1 MTS2-50
C21 LOW M1 sliding cover open limit switch
SCLSCLI /acro0 44 1 MTS2-48
C20 LOW M1 sliding cover close limit switch
PAFAULTI /acro0 45 1 MTS2-46
C19 LOW power amplifier fault IEZEROI /acro0 46 1 wire-wrap
C18 LOW incremental encoder zero pulse detected
IEDREADYI /acro0 47 1 wire-wrap
C17 LOW incremental encoder data ready handshake
IEDCHI /acro0 48 1 wire-wrap
A1 HIGH incremental encoder data l.s.b.
IEDCHI /acro0 49 1 wire-wrap
A2 HIGH incremental encoder data
IEDCHI /acro0 50 1 wire-wrap
A3 HIGH incremental encoder data
IEDCHI /acro0 51 1 wire-wrap
A4 HIGH incremental encoder data
IEDCHI /acro0 52 1 wire-wrap
A5 HIGH incremental encoder data
IEDCHI /acro0 53 1 wire-wrap
A6 HIGH incremental encoder data
IEDCHI /acro0 54 1 wire-wrap
A7 HIGH incremental encoder data
IEDCHI /acro0 55 1 wire-wrap
A8 HIGH incremental encoder data m.s.b.
SHBLS2I /acro0 56 1 MTS1-55
A9 LOW shutter B moving SHBLS1I /acro0 57 1 MTS1-53
A10 LOW shutter B open spare 58
spare 59
SHALS2I /acro0 60 1 MTS1-51
A13 LOW shutter A moving SHALS1I /acro0 61 1 MTS1-49
A14 LOW shutter A open spare 62
spare 63
SIGNAL BOARD CHANNEL TERMINAL STRIP
AIO PIN DESCRIPTION spare
PAVREFO /aio0 OUT-1 TS2-1,
A32-C32 velocity reference VANGLI /aio0 IN-0 TS2-5, 6
A1-C1 M3 vertical angle spare
WINDI /aio0 IN-2 TS2-?, ?
A3-C3 wind speed spare
PACURI /aio0 IN-4 TS2-3, 4
A5-C5 mirror 3 motor current spare
spare
spare
spare
TESEI /aio0 IN-9 TS2-?, ?
A10-C10 tube temperature spare
spare
TEM1I /aio0 IN-12 TS2-?, ?
A13-C13 M1 temperature TEEMI /aio0 IN-13 TS2-?, ?
A14-C14 EMMI temperature spare
spare
10.5.1 I/O Boards
Jumper Settings
VME BOARD JUMPER SETTING STATE FUNCTION
ACRO 9481 J1, J3, J5, J7 Installed
Enables internal pull-up to +5V of the I/O lines J2, J4, J6, J8 Installed Enable internal threshold reference of the input
J17 Base address: Base address:
board 1; 5-6 installed ffff1000 hex (/acro0)
board 2; 1-2 and 5-6 installed
ffff1400 hex (/acro1) J19 Installed Short supervisory and non-privileged access
J20 Omitted SYSFAIL is not asserted after reset
VMIC,VMIVME-3111, analog I/O Default setting is: analog inputs; 16 differential, -10 to +10V
analog outputs; single-ended, -10 to +10V
J1 Installed Ground P3 return
J2 Installed Ground P3 sense
J3 Omitted 5V full scale input
J4 1-1 installed Bipolar analog inputs
J5 2-3 installed Auto input gain adjust
J6 Omitted Unipolar analog inputs not enabled
J7, J8 Omitted Output test is validated
J9, J10, J11 Omitted P3 inputs enabled
J12 1-2 installed Bipolar analog outputs
J13 Omitted 20V full scale output range
J15 1-2 installed 20V full scale input range
J17 to J24 Omitted Differential input
J27 to J34 Omitted Differential input
J25 Omitted 2.5Vdc reference unused
J26 Installed 10Vdc reference used
J35 Installed Ground P2 sense
J36, J37 Base address: Base address:
board 1; J36: 0, 1, 2, 3, 6 and 7 installed
ffff30000 hex (/aio0) J37: 0, 1 and 2 installed
J37-3 Omitted short non-privileged access
J38 2-3 installed Auto input zero adjust
J39 Installed Ground analog outputs return
J40 Omitted 5Vdc reference unused
J41 Omitted Ext. trig not connected to P2 ground sense
J42 1-2 installed Ext. trig rtn connected to P2 ground sense
10.6 MAINTENANCE
INFORMATION
10.6.1 Drawing List
TITLE/ SUB-TITLE SHEET NUMBER LAST UPDATE
DRAWING NUMBER M3 Motor Control
- Functional Block Diagram
25-04-89 CS-E-1457
- M3 Motor Control Chassis
09-10-89 CS-E-1515
- M3 Vertical Position Interlock M3-2 Unit
18-06-89 CS-E-1535
- M3, M1 Sliding Cover Control
25-04-89 CS-E-1508
- M3-2 Unit
26-06-89
CS-E-1514
- Limit Switch Connections
11-01-89 CS-E-1627 M3 Baffle Control
- M3-2 Unit
09-10-89
CS-E-1662
- Baffle Cabling
09-10-89 CS-E-1669
- Baffle Control Board
CS-P-1662 Interconnections
- Chassis Cabling Overview
27-06-90 CABOVER3.SCH - M1 Cover-M3 Baffle
- Vertical Position Interconnections
18-06-90 CS-E-1518 Shutter Control M3-1 Unit
- Arm A Control
1
03-02-91 CS-E-1715
- Arm B Control
2
03-02-91 CS-E-1715 - List of Components 3
- PCB CS-P-1715
M3-1 Unit Mounting Plate
18-06-90 CS-E-1562
- Cabling Overview
26-06-90 CABOVER1.SCH
M3-2 Unit Mounting Plate
18-06-90 CS-E-1527
- Cabling Overview
26-06-90 CABOVER2.SCH
M3 Cabling Overview
05-09-90 EXTOVER.SCH Interconnections M3-1, M3-2 Units
- Cables C1 and C4
05-09-88 CS-E-1563
- Cables C2 and C3
18-06-90 CS-E-1564
Cable Analog Interface
25-04-89 CS-E-1566 10.6.2 Data Sheets
DESCRIPTION NO. OF SHEETS Inland Power Servo Amplifier DCM 70/14 Operating Instructions
11 ESO 32-bit Incremental Encoder Counter Card
Heidenhain Incremental Encoder RON 705 2
Heidenhain Evaluation and Interpolation Electronics EXE 702B
2 Saunders-Roe Mercury Tilt Switch - Part TS8 1
Accustar Ratiometric Inclinometer 5
.
