ACAM Requirements
The science requirements were derived from a review of
the
science drivers for ACAM.
| ACAM (auxiliary-port camera) is a new instrument for the
Cassegrain cluster on the WHT. It will offer high-throughput imaging (~
0.25 arcsec/pixel), and low-resolution spectroscopy, over a field
of diameter ~ 8 arcmin. ACAM will replace the current auxiliary-port
imager (field 1.8 arcmin).
|
| Last update
| Requirement/constraint
| Optimum value
| Acceptable value
| Comments
| Status
|
| 01/11/2007
| Field of view
| >= 8.3 arcmin
|
>= 8.3 arcmin
|
| Fixed: 8.3 arcmin
|
| 01/11/2007
| Wavelength range
|
350 - 1000 nm
|
360 - 850 nm
|
|
Fixed: 350 - 1000 nm
|
| 01/11/2007 | Observing modes
|
Imaging & slit spectroscopy |
Imaging & slit spectroscopy | |
Fixed: imaging & slit spectroscopy
|
| 01/11/2007
| Imaging scale
| ~ 0.25 arcsec/pixel
| ~ 0.25 arcsec/pixel | |
Fixed: 0.25 arcsec/pixel
|
| 01/11/2007
| Image quality
| Should not degrade best seeing
| Some degradation at large radius acceptable | |
Feedback from optical design required
|
| 01/11/2007
|
Throughput (excluding telescope, filters, CCD) |
> 0.8 (350 - 380 nm)
> 0.8 (380 - 1000 nm) |
> 0.6 (350 - 380 nm)
> 0.75 (380 - 1000 nm) | |
Feedback from optical design required |
| 01/11/2007 |
Broad-band filters | 7
positions, 76 mm diameter
| 7 positions, 76 mm diameter
|
|
Fixed: 7 positions, 76 mm diameter |
| 01/11/2007
|
Narrow-band filters
| 7 positions up to 76 mm diameter.
3 positions up to 110 mm diameter
| 7 positions up to
76-mm diameter. 3 positions up to 110 mm diameter
|
|
Fixed: 7 positions up to 76 mm diameter; 3 positions up to 110 mm
diameter |
| 01/11/2007
| Spectroscopic resolution at 600 nm with 0.75-arcsec slit
| R > 500
| R > 350
|
| Feedback from optical design required, but probably R ~ 500
can be achieved
|
| 01/11/2007
| Dispersing element
|
VPH grating
| VPH or grism
|
|
Fixed: VPH |
| 01/11/2007 |
CCD
|
E2V
2048x4100 x 15-micron pixels
|
|
|
Fixed:
E2V
2048x4100 x 15-micron pixels |
| 01/11/2007
| Location
|
Auxiliary port of the Cassegrain acquisition & guidance box
|
Auxiliary port of the Cassegrain acquisition & guidance box
|
|
Fixed: auxiliary port of the Cassegrain acquisition & guidance box |
Comments:
(1)
(2)
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| Reqt. no.
| Last update
| Requirement/constraint
| Optimum value
| Acceptable value
| Comments
| Status
|
| A1
| 01/11/2007
|
Unvignetted field of view
|
9.3 arcmin
| 8.3 arcmin
|
9.3 and 8.3 arcmin correspond to respectively 123 and 110 mm at the
f/ll focal Cass focal plane.
The unvignetted field of view at Cass is ~ 16 arcmin, and ~ 11 arcmin
would be available without compromising the
(annular) Cass autoguider search
field,
but preliminary design work shows that to achieve a good PSF,
the cost (in terms of complexity, expense and throughput) rises rapidly with
field diameter above ~ 8 arcmin.
| Fixed:
8.3 arcmin
|
| A2
| 01/11/2007
| Wavelength range
|
350 - 1000 nm
|
360 - 850 nm
|
|
Fixed at 350 - 1000 nm
|
| A3
| 01/11/2007
|
Imaging PSF (80% encircled-energy diameter)
as function of radius r
|
380 - 1000 nm:
< 0.25” for r < 4.15’
350 – 380 nm:
< 0.25” for r <1.0’
<0.5” for 1.0 < r < 4.15’
|
380 - 1000 nm:
< 0.3” for r < 4.15’
350 – 380 nm:
< 0.35” for r < 1.0’
< 0.7” for 1.0 < r < 4.15’
|
Trade-offs are required between
(1) PSF as a function of wavelength and radius,
(2) optical complexity, and
(3) throughput.
The PSF within the central 2 arcmin should not degrade
the seeing (i.e. should offer as good an imager as aux port).
Optimising the PSF in the UV and at large radius are both demanding
in terms of optical materials and number of components, and should
be given less weight than providing good PSF in BVRI and at smaller
radius.
| Feedback from optical design required (but a reasonable compromise
has already been achieved).
|
| A4
| 01/11/2007
| Atmospheric dispersion compensation
|
Not required
|
Not required
| In U and B, for ZD < 45 deg, the PSF will be degraded
relative to natural seeing,
but it was decided at an early stage that the cost of remedying
this (in terms of optical complexity, expense and throughput)
does not justify building an ADC.
|
Fixed: no ADC
|
| A5
| 01/11/2007
| Scale at science detector
| 0.25 arcsec/pixel
| 0.25 - 0.33 arcsec/pixel
| The best seeing (0.5 arcsec) should be adequately sampled.
| Fixed: 0.25 arcsec/pixel
|
| A6
| 01/11/2007
| Distortion
| < 0.5% differential distortion between wavelengths
350 and 1000 nm for r < 0.9 arcmin, and < 1% at larger radii
| < 1% across field
| 0.5% corresponds to ~ 0.3 arcsec at a radius
of 0.9 arcmin (that of the current aux-port camera).
Larger distortions are undesirable, but at large radius
are probably inevitable, given the design constraints, and they will
have to be dealt with as part of the data-reduction.
| Feedback required from optical design, but 1% looks achievable
|
| A7
| 01/11/2007
| Flexure
| < 1 pixel during a half-hour exposure
| Same as optimum.
|
| Met by the current mechanical design
|
| A8
| 01/11/2007
| Throughput (excluding telescope mirrors, filters and CCD)
|
> 0.8 (350 - 380 nm)
> 0.8 (380 - 1000 nm)
|
> 0.6 (350 - 380 nm) (i.e. at least as good as the current
PF imager)
>0.75 (380 - 1000 nm)
|
For a coating that covers 350 - 1000 nm, up
to 2% per surface may be lost.
For 400nm -1000nm,
<1% per surface can be achieved.
CaF2, with its low refractive index, is probably not worth AR-coating.
|
Feedback from optical design required (current throughput ~ 0.72)
|
| A9
| 01/11/2007
| A&G mirror throughput
| > 0.96 for 350 - 1000 nm
| > 0.9 for 350 - 1000 nm
|
| Coatings under investigation
|
| A10
| 01/11/2007
| Broad-band filters
|
7 filter slots, for 6 filters up to 80 mm diameter
and 5mm thick (U B V R I Z
provided) plus one clear-glass position.
The filters should be slightly larger than
the beam, to allow for tilting to remove ghosts.
The filter throughput should be > 0.8.
Near pupil, so good surface quality required.
|
As 'optimum' except that maximum diameter 76 mm would
be acceptable
|
Location: not critical, but ideally
before the narrow-band filters, to remove bulk of energy from beam
before it gets scattered by the many layers in the narrow-band
filter.
|
Frozen: current design meets optimum requirements
|
| A11
| 01/11/2007
| Narrow-band (>= 1.5 nm) filters
|
7 filter slots (6 filters + clear-glass position) for filters up to
80 mm in diameter, and up to 10 mm thick, with the
option of mounting instead 3 filters up to 110 mm in
diameter.
The filter mounts should allow for tilt, to minimise ghosting.
The change of transmitted wavelength with radius in the field of view
should be < 0.5 nm (i.e. < 1/3 the typical bandpass).
Near pupil, so good surface quality required.
|
As under 'optimum'.
|
The location of the narrow-band filters should be chosen to minimise the
*range*
of angles of incidence of incoming rays, to minimise the range of
wavelength shifts. A constant wavelength shift across the whole
field is OK, a difference between on-axis and edge of field is
more problematic.
It will be possible to use ING's collection of square 50-mm narrow-band
filters, but they are smaller than the likely pupil diameter, so will
suffer some vignetting.
|
The location has been fixed at the camera pupil,
the wavelength shifts still need checking. The other requirements will
all be met by the current mechanical design.
|
| A12
| 01/11/2007
| Filter throughput
| > 0.8 peak for the new broad-band filters;
the existing narrow-band filters have lower throughput
| > 0.8
|
| Fixed: 0.8 is known to be achievable
|
| A13
| 01/11/2007
| Filter surface quality
| Must not significantly degrade the best seeing
| Must not significantly degrade the best seeing
|
The filters are in a near-collimated beam, so nearly all surface aberrations
contribute to the PSF of every image.
| Fixed requirement, but filters not yet sourced
|
| A14
| 01/11/2007
| Ghosts of images in the field of view
| < 1% intensity
| < 2% intensity
|
The filters should be slightly larger than the beam, to allow tilting
(within the mount) by typically a few deg, to reduce ghosting.
For the narrow-band filters, this will have a small effect on the bandpass,
which needs to be calculated.
| Fixed: mechanical design meets this requirement
|
| A15
| 01/11/2007
| Filter-change overheads
| It should take less than 30 sec to move a filter wheel
from one filter position to another, and it should take < 10 minutes
to take a filter wheel out of the camera and slide in another
(pre-prepared) wheel
|
|
| Fixed: the current mechanical design meets the requirements
|
| A16
| 01/11/2007
| CCD QE
| Peak QE >= 0.9; QE ~ 0.5 at 400 and 900 nm
| Less than 10% worse than optimum
| The aim is to provide total camera+CCD throughput which
is better at most wavelengths than offered by the current camera.
| Fixed: the E2V CCD meets the optimum requirements |
| A17
| 01/11/2007
| CCD fringing
| < +-1% at 800 nm
| < +-2% at 800 nm
|
| Fixed: E2V CCD meets the requirements |
| A18
| 01/11/2007
| Availability
| Whenever PF is not in use, and deployable in less time than
it typically takes (2 min) to slew the telescope to a new target
(for rapid response to GRBs etc.)
|
|
| Fixed: the current mechanical design meets these requirements
|
|
|
|
|
|
| | |
Comments:
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| Reqt. no.
| Last update
| Requirement/constraint
| Optimum value
| Acceptable value
| Comments
| Status
|
| B1
| 01/11/2007 | Slits
|
Selection of slits 8.3 arcmin long, with fixed widths of 0.5, 0.75, 1,
1.25, 1.5, 1.75, 2 and 10 arcsec. The slit mask should move out of the beam
for imaging. Repeatability of positioning should be < 20 microns perpendicular
to slit direction, and < 0.1 deg in rotation.
The position of the slit along the optical axis must be adjustable for
initial focusing of the spectrograph.
|
As 'optimum', but with slit length = 5 arcmin, and widths restricted to
0.75, 1 and 1.5 arcsec.
| More slits widths & slit masks (for
calibration & commissioning) can be made available.
|
Fixed: as 'optimum'
|
| B2
| 01/11/2007
| Acquisition onto the slit
|
Via viewing the
field in imaging mode, positioning the target on a predetermined pixel,
then switching to spectroscopic mode.
| As 'optimum'
| There will be a telecope focus offset between imaging and
spectroscopic modes.
|
Fixed: as 'optimum'.
|
| B3
| 01/11/2007
|
Spectroscopic resolution at 600 nm with 0.75-arcsec slit
|
380 – 1000 nm:
R > 1000 over central 0.5 arcmin diameter
R > 500 over rest of field
350 – 380 nm
R > 500
over central 1 arcmin diameter
|
380 – 1000 nm:
R > 500 over central 0.5 arcmin
R > 200 over rest of field
350 – 380nm
R > 250 over central 1 arcmin
|
The
key requirement is good spectroscopic resolution on-axis, in the
visible range.
In the UV, the spectroscopic resolution will be poorer (because
the aberrations are larger), but the impact of this on the science
is relatively small.
Off-axis, the spectroscopic resolution is also degraded,
but the impact of this on the science is again small, because most
spectroscopy will be of single on-axis targets.
| Feedback
from optical design required, but R ~ 500 looks achievable
|
| B4
| 01/11/2007 | Disperser
| VPH, in Littrow configuration
| Grism
|
VPH is preferred over a grism because the aberrations introduced are smaller,
and because
of the higher throughput.
Requires order-sorting filter (installed with the VPH
or in broad-band filter wheel).
The disperser will probably be ~ 50 mm thick.
| Frozen: VPH (probably 450 lines/mm, but feedback from
optical design is required)
|
| B5
| 01/11/2007 | Disperser throughput
| 0.8
| 0.8
|
| Feedback from optical design is required
|
| B6
| 01/11/2007
|
Image width (80% of intensity integrated along spatial direction)
perpendicular to dispersion direction
|
380 - 1000 nm:
< 2 pixels on axis
< 3 pixels over rest of field
350 – 380 nm:
< 2 pixels on axis
< 4
pixels over rest of field
|
380 - 1000 nm:
< 3 pixels on axis
< 4 pixels over rest of field
350 – 380 nm:
< 3 pixels on axis (full field not required)
|
| Feedback from optical design required, but
optimum requirement will probably be achieved
|
| B7
| 01/11/2007
| Flexure
| < resolution/2 at the CCD
in either the spatial or dispersion directions
| Same as optimum.
|
| Feedback required from optical design
|
| B8
| 01/11/2007
| Wavelength calibration
| Illumination of ACAM (at least central 1 arcmin of slit)
by light from existing Cass calibration
lamps
| Other means of illuminating ACAM with arc spectra
|
|
Fixed: meets optimum requirement
|
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| Reqt. no. |
Last update
| Requirement/Constraint
| Optimum value
| Acceptable value
| Comments
| Status
|
| C1 |
01/08/2007 |
Camera Plate Scale |
0.25”/pixel |
0.25”/pixel |
Provides good sampling for best
seeing 0.5” |
Fixed @ 0.25”/pixel |
| C2 |
01/08/2007 |
Pupil
Size | 50mm |
>40 mm <70mm |
Larger pupils are worse for nb
filters & increase the optical path length.
Small pupils increase the complexity
of the design
| Currently 45 mm diameter.
Driven by optical design image quality requirement. |
| C3 |
01/08/2007 |
Pupil distance to next optical lens |
>50 mm |
Half thickness of GRISM/VPH plus 7.5
mm. | NB filters
& Grisms will sit at pupil. Optical design optimizes by brining next
optical component close to pupil. Filter wheels & structure
constrain this distance |
Frozen.
41.5 mm |
| C4 |
01/08/2007 |
VPH/GRISM/FILTER assembly separation distance to next lens. |
>50 mm. This allow a shutter to be fitted. |
>7.5 mm. this allows for clearance between dispersing element and
next lens. Shutter has to be located else ware. | |
Frozen.
15.5 mm. This is the edge separation. |
| C5 |
01/08/2007 |
Camera Re-focus
for different wave lengths |
Secondary Re-focus.
NB. encoder resolution is 3 microns. Realistically a step change of
10 microns should be used. |
Instrument refocus is an option. |
If there is a clear gain in image
quality in both imaging and spectroscopic modes by using a focus
stage in the camera – then this can be incorporated in the design.
|
TBC. Currently Secondary focus.
NB x 20 for shift if focus is done in camera.
( ) indicate achievable values
360 nm 23 microns. (20)
450 nm 31 microns. (30)
550 nm 0 microns
650 nm -32 microns. (-30)
820 nm -57 microns. (-60)
885 nm -62 microns. (-60) |
| C6 |
01/08/2007 |
Camera Optical length I.e. from
telescope focus (which is
close to the outer diameter of the A&G box)
to CCD |
<600 mm |
<850 mm |
Making the instrument length short
reduces the effects on mechanical, thermal and optical stability.
Distance between certain optics must be maintained to accommodate
and optimise the use of a slit mask, filters, Grisms and a shutter. |
Fixed. 850 mm |
| C7 |
01/08/2007 |
Filter tilt
angle | x deg |
x deg |
To
minimise ghosting | TBC from optical design. |
| C8 |
01/08/2007 |
Baffling |
TBD |
TBD |
To minimise ghosting, light
leaks and scattering. | TBD form opt/mech design |
| C9 |
01/08/2007 |
Secondary Refocus due to
dispersing element |
Camera refocus =>0< 3
Secondary
refocus 1/20 | Camera refocus =>0<10
Secondary
refocus 1/20 | | |
| C10 |
01/08/2007 |
CAGB ACam science fold mirror |
Size = 11 arcmin .
Elliptical mirror size
Minor axis = 190 Major axis = 270
coating optimised for λ range
Surface finish λ/20 |
Size = 11 arcmin.
Elliptical mirror size
Minor axis = 190 Major axis = 270
coating optimised for λ range
Surface finish λ/20 |
New coatings to be investigated.
Mirror size set at 11 arcmins which is constrained by the autoguider
Patrol field |
Fixed. @ 11 arcmins diameter field. |
| C11 |
01/08/2007 |
CCD |
E2V 2048x4100x15micron pixels.
|
Marconi.
2047 x 4611 x 13.5 micron pixels. |
E2V same QE curve and fringe
performance as the ISIS Red+ detector. The central 2kx2k pixels can
be windowed off to improve readout speed. |
Fixed. E2V order complete. Delivery
July 2007. |
| C12 |
01/08/2007 |
CCD Fringing |
+/- 1% at 800nm |
+/- 1% at 800nm |
E2V meets fringing requirements |
|
| C13 |
01/08/2007 |
CCD cryostat window |
Flat window
Distance from window to CCD > 10mm.
Distance from window to preceding
optical element. >10 mm
Material should be fused silica to
avoid background radiation from the glass |
Active Window.
Distance from window to CCD = > 7.5
mm.
Distance from window to preceding
optical element. >7.5 mm .
Material should be fused silica to
avoid background radiation from the glass |
It is preferred to have a flat
cryostat window in the optical design to enable the CCD to be used
at any focal station. This also means a standard mounting
arrangement can also be used. Image quality must meet requirements;
if this is not the case then an active window should be incorporated
in the optical design. Note consideration for the effects of vacuum
and atmospheric pressure across the window need
|
Frozen. Active cryostat window.
Distance from optical edge to CCD
= >7.5mm
|
| C14 |
01/08/2007 |
Edge
dimension of cryostat window to CCD |
>7.5mm <12 mm |
>7.5mm <12 mm |
To allow for radiation shield and
thermal isolation across vacuum void |
Fixed at 7.5 mm |
| C15 |
01/08/2007 |
Edge
distance between cryostat window and preceding lens. |
>10 mm |
>5 mm |
to allow for adjustment and clearance for CCD
window |
TBC |
| C16 |
01/08/2007 |
Camera F.O.V |
8.3 arcmin diameter |
8.3 arcmin diameter |
| Frozen. 8.3 arcmin diameter |
| |
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Comments:
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| Reqt. no. | Last update | Requirement/Constraint
| Optimum value
| Acceptable value
| Comments
| Status
|
| D1 | 01/08/2007
| Instrument Entrance
aperture | 8.3 arc min |
8.3 arc min |
What about the corners? | TBD. |
| D2 | 01/08/2007
| Patrol Field |
Keep current patrol field |
Maximise fold flat with out
compromising ability to find adequate guide stars |
Ref. Document : CAGB autoguider
patrol field and fold flat.pdf |
Frozen @ 20% lose of original Patrol
field |
| D3 | 01/08/2007 |
Calibration source |
Use current CAGB unit.
Fold flat to feed light on axis into
ACam is mounted on an off axis rotation stage combined with the CAGB
science fold mirror |
Use current CAGB unit.
Fold flat to feed light on axis into
ACam is mounted on an off axis rotation stage combined with the CAGB
science fold mirror |
This has been modelled and provides
a cost effective and efficient calibration source for ACam
spectroscopy |
Frozen.
Utilise current small auxport fold
flat |
| D4 | 01/08/2007
|
Weight of instrument
Out of Balance Moment |
80 kg
< 100Nm |
110 kg
< 150 Nm |
Instrument must be counter balanced
to reduce the out of balance torque on the rotating cass cluster. |
|
| D5 | 01/08/2007
| Instrument Interface |
Open aperture flange is 220mmĘ.
Fixing 12 x M6 equispaced on a PCD of 230mmĘ. |
Current auxport interface flange.
Open aperture flange is 220mmĘ. Fixing 12 x M6 equispaced on a PCD
of 230mmĘ. | Current mount can be stiffened to minimise flexure |
Fixed. Current CAGB auxport
interface flange |
| D6 | 01/08/2007 |
Instrument Space Envelope |
Optical axis and interface flange as
datum. 600 mm (long) x 450 mm wide x 450 mm (high) |
Optical axis and interface flange as
datum. 850mm (long) x 600mm wide x 600mm (high) |
This excludes the actual cryostat.
NB. Electronics etc. can be mounted outside the space envelope after
considerations for collisions and outer balance forces have been
taken into account. |
TBC |
| D7 | 01/08/2007 |
Focal plane Deflection |
< 25 microns from optical axis at
CCD in any observing orientation. |
< 30 microns from optical axis at
CCD in any observing orientation |
First pass flexure analysis
indicates instrument structure can deliver 30 microns deflection
through a 90 degree gravity vector change. More detailed analysis
required, including, thermal, vibration and shock. |
work in progress |
| D8 | 01/08/2007 |
Focal Plane Tilt |
< 0.06 mill-radians tilt from focal
plane at any observing orientation |
< 0.1 milli-radians tilt from focal
plane at any observing orientation |
First pass flexure analysis
indicates instrument structure can deliver 12 arcsec tilt through a
90 degree gravity vector change. More detailed analysis required. |
work in progress |
| D9 | 01/08/2007 |
Shutter | 100m
diameter clear aperture prontor shutter - modified for air
operation. Position after Pupil and next lens element. |
100m diameter clear aperture prontor
shutter - modified for air operation. Position up stream of Broad
Band filters. | Relative large aperture allows the shutter to be fitted in many
positions in the camera. Instrument is designed to be light tight -
essential down stream of shutter |
Frozen. Air operated. Up stream of
Broad-band filters. On entrance plate of filter box. |
| D10 | 27/08/2007 | ACam
Instrument Change. |
2hrs | 2hrs | to remove of refit ACam and
reblance telescope |
Fixed. 2hrs |
| D11 | 27/08/2007 | Mechanical
Handling. |
Lifting points for the handling & storage of ACam are required. |
Lifting points for the handling & storage of ACam are required | |
Fixed. Lifting points incorporated |
| D12 | 27/08/2007 | Light &
Dust tight enviroment to maintain on the CAGB & ACam at all times. |
Protective cover to be provided when ACam is not mounted for CAGB &
ACam |
Protective cover to be provided when ACam is not mounted for CAGB &
ACam | |
Fixed. Coveres to be design & manufactured. |
| D13 | 27/08/2007 | ACam
handling trolley |
Storage trolley required for ACam |
Storage trolley required for ACam | |
Fixed.Trolley to be designed and manufactured |
| D14 | 27/08/2007 | Instrument
Change document |
Yes |
Yes | |
Fixed. Yes |
| D15 | 27/08/2007 | Optical
Alignment document |
Yes |
Yes | |
Fixed. Yes |
| D16 | 27/08/2007 | Maintenance
& Spares Document |
Yes |
Yes | |
Fixed. Yes |
| D17 | 27/08/2007 | No lights
sources when observing e.g. from LEDs |
Yes |
Yes | |
Fixed. Yes |
| D18 | 27/08/2007 | By design
reduce risk of injury to personnel to a practicle minimum |
No sharp edges.
Provide lifting points. Filter changes & instrument inspection
possible from enclosed step ladders. |
No sharp edges.
Provide lifting points. Filter changes & instrument inspection
possible from enclosed step ladders | |
Fixed. Yes |
| | 27/08/2007 | Filter
change & storage facilities |
Provide a dedicated change and storage area for filters. |
Provide a dedicated change and storage area for filters. | |
Fixed. Yes |
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Comments:
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| Reqt. no. |
Last update |
Requirement/Constraint
| Optimum value
| Acceptable value
| Comments
| Status
|
| E1 |
01/08/2007
| Slit unit number of positions |
1,2,3,4,5
& out (0) |
1,2,3 & out (0) |
| Fixed. 1,2,3 & out (0) |
| E2 |
01/08/2007 |
Slit Encoding at
position |
Binary encoding |
Binary encoding |
2 micro switches provide binary
encoding with high (1) and low (0) states. |
Fixed.
|
Switch
A |
Switch
B |
Position |
|
1 |
1 |
Position
“Out” and “Change position 2”. |
|
0 |
1 |
Position
“1” and “Change Position for slit unit 3” |
|
1 |
0 |
Position
“2” |
|
0 |
0 |
Position
“3” and “Change Position for slit unit 1” |
|
| E3 |
01/08/2007 |
Slit Detent
|
In/Out |
In/out |
Modified - Air operated detent. Spring out
(weak). Air out (hard).
Reed switch indication. in/out.
24V DC 3 port 2 way spool valve
operation |
Fixed.
Air operated detent. Spring out (weak). Air out (hard).
Reed switch indication. in/out |
| E4 |
01/08/2007 |
Slit Drive |
24V DC motor On/Off
Direction CW / ACW |
24V DC motor On/Off
Direction CW / ACW | |
Fixed. 24V DC motor On/Off
Direction CW / ACW |
| E5 |
01/08/2007 |
Filter/Grism
wheel. number of positions. |
variable. 1 to 7 |
variable. 1 to 7 |
2 wheels in total. |
Fixed. Variable. 1 to 7 |
| E6 |
01/08/2007 |
Filter wheel
counting & encoding |
Microswitch indication. Normally open switch (0).
When closed (1) Filter at a position. Count position referenced from
zero set switch. |
Microswitch indication. Normally open switch (0).
When closed (1) Filter at a position. Count position referenced from
zero set switch. | 2 wheels in total |
Fixed.
Microswitch indication. Normally open switch (0).
When closed (1) Filter at a position. Count position referenced from
zero set switch. |
| E7 |
01/08/2007 |
Filter wheel
Detent |
In/Out |
In/Out |
2 wheels in total.
Air operated detent.
Spring IN air OUT.
24V DC 3 port 2 way spool valve operation |
Fixed. Air operated detent. Spring IN air OUT. |
| E8 |
01/08/2007 |
Filter wheel
drive |
24V DC motor On/Off
Direction CW / ACW |
24V DC motor On/Off
Direction CW / ACW | |
Fixed. 24V DC motor On/Off.
Direction CW / ACW |
| E9 |
01/08/2007
| Slit & Filter box access doors interlock. |
Disable mechanism when access door(s) open. |
Disable mechanism when access door open. |
4 in total.
Microswitch
hardwire into motor drive |
Fixed. Microswitch hardwire into motor drive |
| E10 |
01/08/2007
| Shutter |
open / closed |
open/ closed |
24V DC 3 port 2 way spool valve
operation. operated from SDSU controller status Open/closed feed
back inputs required. |
Fixed.
24V DC 3 port 2 way spool valve operation.
operated from SDSU controller status Open/closed feed back inputs
required. |
Comments:
(1)
(2)
Document History
| Document Location |
This document is only valid on the day
it was printed.
Printed on 27 August 2007
The source of the document can be found
at:
http://www.ing.iac.es/~eng/private/projects/ACAM/ACamweb/documents/current/Hig_Lev_Req_Current.htm |
| Owner of Document |
Acam Project Manager. Kevin Dee |
| Authorised to make changes. |
Acam Project Manager. Kevin Dee,
Acam project Scientist. Chris Benn,
ING Head of Engineering. Don Carlos |
| Revision Approval by e-mail acknowledgement. |
Acam Project Manager. Kevin Dee,
Acam project Scientist. Chris Benn,
ING Head of Engineering. Don Carlos |
| Revision History |
When document is revised, first save current
document as "Hig_Lev_Req_Old_yyyymmdd" and save in same
directory. Revised file should be saved as
"Hig_Lev_Req_Current.htm". This means the web page can remain
the same and is always the current up to date version |
| Revision Date |
Summary of changes |
Changes Made by |
Previous Revision File name |
Approved by |
| 09/08/2007 |
Created as htm. file and placed on acam web
pages. Requirements transferred from existing documents amended
and updated. |
Kevin Dee |
N/A |
Kevin Dee |
| 27/08/2007 |
Mechanical requirements D10-D18 added. Input
Juerg Rey |
Kevin Dee |
Hig_Lev_Req_old_20070827 |
Kevin Dee |
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