COMDYNA GP-6 - test-drb@ccmp.vtda.org

4 Nov 2002

Hi Pat
 The link to the lab stuff was old so I did a little looking
around and found:

http://routh.ee.adfa.edu.au/%7Eirp/Teaching/Control_Theory_2/Labs.html

 It shows some uses of the GP-6 for analyzing control
systems.
Dwight

...
 From: "Patrick Finnegan"
&lt;pat(a)purdueriots.com&gt;

On Mon, 4 Nov 2002, Doug Coward wrote:

    You wrote:
  One last thing - does anyone have an idea of what
the "SW" and "OP" jacks
 at the bottom of the front panel are, 
  Here is a quotes from a GP-10 brochure:
   "The OP termination is the system's mode control bus.
 For centralized integrator mode operation, the SW
 switch control is patched to the OP bus."

   My take on this is that if you are not controlling
 the operation mode from a digital computer or other
 external device, then you need to jumper OP to SW
 for each integrator in order to control the mode
 from the front panel buttons.
   IC = Initial Condition mode
   HD = Hold mode
   OP = Operate mode
   RO = Repetitive Operation mode 
Ummm, I seem to have an older GP-6 that has no such front-panel switches.
It just has the 'Y/POT Select', 'X Select' and 'Compute time'
knobs on the
front (along with the 8 coefficient pots).  There's also four small
potentiometers, with a slotted shaft (for using a tweaker screwdriver for
adjustment) along the bottom of the front (on the banana jack half)
which are unlabelled.... any ideas what they are for?  They seem to be
missing from the model pictured on COMDYNA's web site.

  > and how to use the multipliers?  I
 > can't quite seem to get them to 'multiply'... 
I guess you can attribute my lack of understanding this part to my lack of
usage of analog computers... sometimes engineers need to be a little more
reasonable in their descriptions IMHO.

  Here is a quotes from a MICROPATCH brochure:
   "Two multiplier networks may be arranged as
 multipliers, dividers, squarers, or square root
 extractors of input variables. Two attenuator-switch
  networks are needed to electronically program a
 multiplier or divider. One output is patched to the
 "X" terminal; the other is patched to the "Y" terminal. 
Ok, got that

  When the network is patched as an input to an
 operational amplifier that has a resistor as the
 feedback, the amplifier's output is the product
 of the input variables. When the network is 
Does 'the network' refer to the output of the multiplier ( the terminal
not labeled 'x' or 'y')?  If so, that's what I've been doing...

  patched as the amplifier's feedback, the
amplifier
 output is the quotient of the two input variables." 
But I just used up the X and Y inputs, how am I supposed to use the
multiplier as feedback for the op-amp?

It'd be helpful if someone had an example schematic or block diagram of
some sort...

Pat
--
Purdue Universtiy ITAP/RCS
Information Technology at Purdue
Research Computing and Storage
http://www-rcd.cc.purdue.edu

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