[Test-Equipment] Graphics Interface for HP Network Analyzer

[Eric Lemmon]

Dave,

Thanks for a very concise response.  I now know what the problem is, and
I have another route to a solution.  You're the third person to
recommend the NI GPIB interface card, so I know that I'll need to find
one for my Windows 98SE computer.

One thing, though- I don't want to buy an obsolete printer, even if it
will produce plots of what's on the analyzer screen.  I do have an HP
Laserjet 6P printer, as well as an HP Photosmart 1215 color inkjet
printer.  Even if the Laserjet 6P could accept the HPGL code, my primary
interest is getting the analyzer image into my computer; once I have
captured the image of the analyzer screen, I can use Paint Shop Pro to
manipulate the image electronically and perhaps even print it out on my
laser printer.

One response suggested using a shareware program called HP2XX, which
converts the HPGL into an image format that the PC can recognize.  I am
new to the HP-IB implementation; I have known for some time what it can
do, but I have never used it in conjunction with my own lab gear.

The situation appears to have two phases:  First, I must establish
connectivity for data between the HP8752A and my PC, and an NI GPIB
interface card seems to be the solution to that part.  Second, I must
find a way to translate the proprietary HPGL-formatted data into a
text-and-graphics format that the computer and most graphics programs
(like Paint Shop Pro) can understand, and the HP2XX utility seems to be
the solution there.

Is this the most practical means of achieving a reliable interface?  I
know that I can use my digital camera to snap a photo of the screen, but
I'd rather save that solution to use if there is no other way.

73, Eric Lemmon WB6FLY

Dave W8NF wrote:
> 
> Hi Eric,
> 
> A little bit depends on what you really want -
> graphics or data.  I've found that if all I want is
> graphics, I can take a picture with my digital camera
> and that's plenty good enough.
> 
> Here's the mess you've run into:
> 
> The 8752A (and 8753A/B/C) could drive either plotters
> or printers.  If driving a plotter, they issued HP-GL
> code.  If driving a printer, they issued PCL code.
> The old HP Thinkjet was the world's first PCL printer.
> 
> In "the old days", all HP inkjet printers were PCL
> compatible.  However, that required the presence of a
> microprocessor inside the printer.  Nowadays, all
> inkjet printers use a hardware-based protocol, and the
> printer has no processor, only a shift register.  So,
> the PC has to provide the printer the exact bit stream
> required to drive the head.  This is done via the
> printer driver, which is unique to each printer.  Give
> any of today's inkjet printers the old PCL language,
> and they'll print garbage.
> 
> However, the high end LaserJets still run PCL and they
> also can take HP-GL.  A used HP LaserJet 4, 5 or 6
> will do it.
> 
> However, you're still stuck with the fact that it's an
> HP-IB interface on the back, not a parallel port.
> Enter "Intelligent Interfaces" of Stone Mountain
> Georgia.  For $300-$400 they'll happily sell you an
> interface between HP-IB and parallel, and can even
> recommend specific printer models.
> 
> Gosh, this is just TOO complicated, isn't it?
> 
> My preferred low-cost solution is this:
> 
> Go to eBay and find an HP-IB version of the old HP
> ThinkJet.  That'll be a model 2225A/B/C.  I think it
> was the A version that was HP-IB.  They go for $30 to
> $50 on eBay.  They're thermal printers, finding the
> thermal paper is a bit tricky, but a Google search for
> "thermal printer supplies" will probably get you a few
> useful suppliers.
> 
> The 8752 uses programming codes that are similar to
> the 8753 series.  Using an NI card, you could have it
> transfer over the actual S-parameters, which you could
> then dump into Excel.  But that won't look like the
> screen.
> 
> Everything was fine until the printer manufacturers
> started yanking the microprocessors out of the
> inkjets, then it got messy.
> 
> I've got an 8753A at home and just use my digital
> camera!
> 
> 73,
> 
> Dave W8NF