Dear all,
This is what we ended up doing to get a PDL-2 (or PDL-3) laser under 
computer control:

1) we left the stepper motor in place (a standard 4,6 or 8 wire 200 
steps/rev. motor).
2) Bough a microLYNX (www.imshome.com) microstepper controller (about 
300 $/Euro).
3) Connected the motor directly to the controller
4) Connected a 30 V power supply to the controller
5) Connected the controller via RS232 to a PC.
6) Connected a TTL trigger from the scan program to the controller
6) Wrote a 20 line program that gets downloaded via RS232 to the 
controller which:
    a) asks/checks the counter position of the laser
    b) ask the user for a begin wavelength (or wavenumber)
    c) asks the user for a stepsize
    d) on every trigger the stepper motor then advances the defined 
stepsize and waits for the next trigger.

Works like a charm and should work with pretty much every stepper 
motor. Pretty cheap and hardware independent too. Important for our 
laser was that the controller does microstepping (256 steps per 1.8 
degree stepper motor steps = 51200 Steps/revolution). Also, the 
controller is pretty smart, so that it is really easy to program.

E-mail me if you need more info.

Greetings,
Gert

On Jun 21, 2005, at 5:56 PM, Mark Sulkes wrote:

> I've found the user group to be extremely helpful on old equipment
> questions, and this was the case here.  There were both suggestions as 
> well
> as requests for useful results.
>
> Based on all responses, it seems that the Quickbasic program (ND60 and
> variants)that sent commands to the ISA motion control board has fallen 
> into
> total (and probably deserved)oblivion.  There were three kinds of 
> proposed
> fixes:
>
> 1.  Reverse engineering--intercepting commands to the motion control 
> board
> and figuring out necessary basic commands, to be used in a new 
> user-written
> program.
>
> 2.  Someone else had a problem with motion control components of this
> vintage and suggested that the ISA board might only work properly in a
> computer with clock speeds of that vintage (probably 6 MHz or less).  I
> had "upgraded" to an old 100 MHz Pentium 1, so that could be the 
> problem;
> the boards originally came in a PC-XT (8086 based).  I am now 
> patrolling
> the area around the dumpster of our building in hopes of finding an
> appropriate computer.
>
> 3.  Multiple people have encountered a similar problem in old dye 
> lasers
> and have implemented the same solution:  Rip out the old scan motors 
> and
> electronics, leading to a bare lead screw on the grating.  At this 
> point
> put in and couple to the lead screw a new stepper motor (possible to 
> use
> some old components).  It would be possible to get adequate (bare 
> bones)
> control simply by counting pulses applied to the motor driver board.
> Alternatively, a more expensive motion control package, including 
> stepper
> motor with documented scan control firmware, could be installed, and a
> rather versatile scan control routines could be written.
>
> To join or leave the molecular-dynamics-news email list, go to:
> http://www.jiscmail.ac.uk/lists/molecular-dynamics-news.html
>
-------------------------------------
Gert von Helden
Fritz-Haber-Institut der Max-Planck-Gesellschaft
Faradayweg 4-6
14195 Berlin
tel.: +49-30-8413 5615
fax: +49-30-8413 5603

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