We recently had a customer ask us to replace an aging Nematron OIT with a newer Allen-Bradley Panelview Plus 1250. Not knowing what I was getting into, I gladly accepted the work and was given a disc of some files contained on the old OIT, which I was told were written in some type of basic scripting. It took me a couple of days to find out that the scripting is something called 'Optibasic', and there isn't much on the internet about it (at least, as not as I could find with some simple searching). I was, however, able to find a manual for the language on Nematrons website (under Legacy devices), but there is still a lot of the scripting that I don't understand. Does anyone know of any info online that can give me a head start on understanding how this language works?

Thanks up front.

 

It's a good thing Nematron is still in business and posted those old files on their web site, because those and the collective memory of former users are probably all you'll find. I looked at the manuals for a quick refresher, since it's been about 12 years since I even replaced one of these units. Do you have a CRT model or a later LCD version? The OptiBASIC code is the main operating program in these units, but there are separate files called OptiSCREEN that define the actual displays. A given display may have two screen files, one for static text and the second for dynamic data. The OptiSCREEN manual is DOC-IWS-115B. Since we're talking about old school BASIC complete with line numbers and GOTO, there's no telling what kind of spaghetti code you've got. The manuals say a lot about optimizing code for speed, with good reason: The CPU in the IWS-2000 series was only a 4MHz Z-80!

Instead of reverse engineering all of the code, it may be faster to just bring up each screen, match the displayed data to the PLC registers and use that to create a new design spec. There's no built-in alarm handling that I recall. We built screens that looked like virtual 4h x 3w annunciators and applied flashing/reverse video in an alarm state.

Let me know if this has been any help.

Mike

 

It is an older CRT model, yes. I'm slowly peeling back layers of the code and realizing that your idea may be best. As I start to filter things through I find sections of code in one file being referenced in other files and it turns into a mess pretty quickly. Since all we are interested in doing is displaying the process data and alarms, I'm hoping we can just bypass all this mess. The PLC program is fairly well documented, I just think the boss wanted to verify that what we were seeing is what was actually being displayed. However, I think that taking that route may consume too much time. Ill go through it a little more, but your idea is very appealing right now!