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\|\\M1BDR30;\M2SIGN57;\M3NGR25;\M4NGR20;\F2\CVICARM
\F3\C154 EAST DANA STREET
\CMOUNTAIN VIEW, CA. 94041
\F4\←L\-R\/'7;\+R\→.\→S   Telephone:
\←S\→.415-965-0557
\F1\COctober 21, 1976


Dr. Gerald Wilson
Naval Research Laboratory
4555 Overlook Avenue S.W.
Washington D. C.  20375


Dear Jerry:
\J
	Enclosed  is  the   repaired  interface.   We   have  added  all   the
multiplexers and the extra  DAC.  We have also  changed the DAC for  joint
#4.  I  have  enclosed a  list  of corrections  you  should make  to  your
program, to reflect  this new calibration.   Just type DONE  and open  the
proper locations and rewrite them as specified.  When finsihed, 1000G will
get you going again.

	Also enclosed are 8 resistor-diode  assemblies (one spare in case  you
lose one).  These are to  be inserted on each  servo card in the  position
indicated between the  7411 and HI1-201-5.   Follow the annotated  sketch.
First remove these ic's.  Then you must carefully  cut the trace with  the
xacto blade which is also enclosed.   This is the thin trace running  from
the feedthru hole to pin 8 of the left HI1-201-5. Now insert the  assembly
in the hole and carefully solder it in place as shown. Use a long thin tip
soldering iron and be careful not to slop solder on any other traces.  Now
put the ic's back being careful not to bend any pins under. This completes
the fix.

	That fix was for the case of the arm glitching after an OPEN  command.
You may also  get some glitching  after a PAUSE or  GRASP which  immediately
follows a COARSE function.  This is  because the joint positions are  read
after these two functions and if the arm is not where it is supposed to be  a
correction motion is executed at the  start of this next required  motion.
This appears as a  glitch.  COARSE modified functions  don't null out  and
thus the initial error  on the motion immediately  following the PAUSE  or
OPEN.  All other instructions are OK, as the joint angles are not read  in
these cases.  Moral, don't  use a  COARSE motion  just before  a PAUSE  or
GRASP.

	I have also included some  more documentation.  First, the details  on
how the interface works.  You should also refer to the DRV-11 notes in the
DEC handbook.  To make things even simpler, I have included a tape of  our
interface test program.  Load  this like the arm  program, and follow  the
instructions.  It is restarted each time  by typing 1000G, and stopped  by
hitting any key.  It  allows reading of  individual or multiple  channels.
It allows you to drive individual arm joints in Position or Current  mode.
NOTE:  THIS  PROGRAM  DOES NOT  HAVE  PROTECTION FEATURES  LIKE  AUTOMATIC
TIMEOUT, SO  DONT LEAVE  IT DRIVING  JOINTS.  IN  CURRENT MODE,  THERE  IS
ALMOST NO VELOCITY DAMPING, SO  JOINT MOTION IS VERY UNSTABLE...AND  THERE
ARE NO COMPUTER OR ELECTRICAL LIMIT STOPS.  PICK VALUES NEAR 000 TO  START
WITH.  A HIGH CURRENT WILL DESTROY THE  ARM IF A MECHANICAL LIMIT STOP  IS
HIT.  I have supplied you this tape as a convenience... please dont  wreck
the arm with it.
          
        
        
        
	Other documentation includes a schematic of the clock and front  panel
switch circuitry.   Also included  are a  couple of  arm drawings  showing
internal details...they are not complete but  this is all we have. I  have
also included a couple of revised interface schematics showing pin numbers
for your reference.  Please replace your drawings with these.

	I feel that we have now completed our part of the contract, so 
please authorize payment...furthur delays will hurt us both.\.
\←L\→S\←R\-L\/'2;\+L\→L

Yours sincerely,



Victor Scheinman
    President

\←S\→L
\J

Enclosures: Interface test  tape, Absolute  loader tape,  Servo card  mod.
dwg., Updated  program documentation  showing construction  of  Transform,
Interface    connector    wiring     documentation,    Bit     assignments
sheet, Instructions for modifying arm  program becasue  of change  in  DAC
#4, Revised interface  dwg.,arm  layout  dwgs.,  DAC,  A/D  and  MUX  spec.
sheets., Resistor-diode servo card parts, and repaired interface.\.