Finally doing something with it.

A project log for Optronic Laboratories 740A/D Spectrometer

Getting a 1990 vintage spectrometer running on something more modern than MS-DOS

Jerry BiehlerJerry Biehler 11/22/2020 at 12:220 Comments

It's a really nice unit, dual grating with gratings on each turret for UV and Visible spectrum. With the current setup it is good for about 200nm to 1115nm. The Du lamp handles 200-400nm and the tungsten covers the rest. It also has the 740-4P Off Axis Telescope.

So the whole 386 and DOS/BASIC makes it a real pain to use, plus the program is pretty dedicated to doing the QE tests and I really dont want to learn basic to run it plus I would still have to deal with the ISA IO card it runs from,

So i decided to make a new controller. For the hardware interface I ended up going with an Advantech USB-4751 48-Channel TTL Digital I/O USB Data Acquisition Module. It is pretty much the card inside of the old PC but in USB form. It uses two 50 PIN Opto-22 style ribbon connectors instead of the 40 pin headers on the ISA card. To transition to the DB-25 for the boxes I designed a small board that handles the transition from ribbon to DB-25. I did this in Altium since I use it for work. 

Of course one cannot make a board without screwing it up. And boy did I! Every connection was wrong. Somehow I managed to get the order of pins wrong on the 50 pin header and then the footprint I used in Altium for the DB-25 was totally wrong. So I literally did not get one pin right. So I fix that and send of another order to JLCPCB and a week later I get good boards. 

So now that the hardware is "Done" I tackle the hardware. I cant program worth a damn so I use LabVIEW which I also use for work. The advantech DIO device has good LabVIEW drivers that make it pretty easy to build an interface. Well, compared to the first unit I picked up from SeaLevel, it was an older unit and didn't have any really labview drivers and I really didn't feel like figuring it out so I picked up the Advantech. $111 shipped, not bad!