Mark IV Checkout Continuing - 2

[Tom Droege <droege@wwa.com>]

Mid May I will have two student helpers.  I am working frantically so that
I will be ready to go into production line mode when they get here.  This
explains any irritation you all may have sensed from me.  

The Scanner Board is now mostly checked out.  I can now say "start scan"
and the scanner goes through 110440720 states.  It looks like it is doing
everything OK.  But I will have to install a CCD chip to know for sure.  

The most complicated things parts of the system are now working.  Most of
the rest are simple and repetitive parts.   But each thing I test requires
some code to be written, often both PC code and Stamp code.  

Here is a summary of the parts of a Mark IV system:

Electronics:

Camera Board:

This mounts in the camera head and contains switches to drive the clock
lines and a preamplifier and baseline zero circuit.   

10 are here and ready to be checked out.  Most parts are here. 

Power Supply:

We are using standard open frame linear units. 

Individual units available to be assembled.  Two sets in stock

Stamp Board:

The Stamp Board contains a stamp computer and it's connection to a PC.  It
loads 16 DACs that are contained on the board, produces 24 pulses used for
things like loading registers, driving model airplane servo motors, etc..
It also contains a 32 channel multiplexer and a 16 bit ADC.  

Pre-production board is Checked out.  Everything seems to work as designed.
 10 Minor errors. 

Scanner Board:

The stamp board contains the horizontal and vertical scan engines.  These
interract with each other to produce the pulse sequence required for read
out of the CCD. 

Checked Out.  Everything seems to work as designed.  No errors.

ADC Board:

The ADC board contains four 16 bit ADC channels.  Each channel performs
dual slope integration of the double correlated sample of the CCD signal.  

Testing has started.

Motor Board:

The motor board contains nine stepping motor drivers and eight model
airplane servo drivers.  It also contains connectors for 14 position sense
channels.  It contains registers to drive external devices.  One of these
is the power control card that can switch 4 channels of 115 Volt AC power.  

Available for test.  Most parts are here.  One known layout error.  I
forgot the inverters needed by the Model Airplane Servos.  

Memory Board:

This board holds up to 64 Mbytes.  It is loaded from the ADC board and read
out from the PC. 

The baords have arrived, and Merle has stuffed one.  It has passed his
"smoke" tests.  Not many changes from the last design, so I expect it will
work when I get around to testing it.  

TEC Board:

This board contains four feedback controlled power amplifiers to drive four
thermoelectric coolers.  The board receives temperature commands from DACs
on the Stamp board, and closed loop controls the TEC to hold the desired
temperature.  

Avaliable for test.  Most parts are here.

Misc Board:

This is a collection of many small PC boards.  Some are used to mount limit
switches.  Others mount SCR switches to control AC power.  Others are just
convenient connectors to allow devices with short leads, like the model
airplane servos, to be extended.

Available for test.  Most parts are here.  

Mechanics:

Mount:

Again I have scrapped the design.  Now working on a modified fork mount.
It is all a question of designing a box that will be easy to build and
mount.  I now plan to mount everything on a 3' by 4' plywood base.  But the
wood will just be a convenient mount.  It will be able to change dimensions
without anything moving.  
Trying to get all my thoughts in order so that when Mike gets here in mid
May he can detail all the little pieces.

Head:

We are on the third pass for the camera head design.  10 sets of parts are
on order and should show up in two weeks.