We (ACS) design and build embedded industrial controllers for a living. So we use several dozen different software tools, compilers, IDEs, logic synthesis, logic simulation and Computer Assisted Engineering (CAE) tools for printed circuit board design layout. All of these tools have quirks and bugs – some more serious than others.

When I first started this career, printed circuit boards were hand-designed on mylar sheets, one per layer, at a 2:1 scale using stick on pads and various widths of tape to lay down traces. Improvements came with red and blue transparent tape that minimized the number of mylar sheets required as two layers of circuitry could be placed on a single sheet – improving registration.

In the mid to late 80’s Computer Assisted Engineering for circuit board layout became popular – although the tools were expensive. Over time, the number of vendors increased, the PC became the target platform and the prices dropped. Goodbye mylar sheets of artwork. My brother and I initially invested in Design Computation software 20 years ago, and later, when the DOS based tools weren’t up to the task and that company disappeared, we switched to Protel.

We've used Protel Schematic Capture v3.4 and Protel PCB Design v2.8 to design several hundred boards - mainly double-sided, mixed SMT and through-hole, some with hundreds of parts, all sizes - no problems. You build up a library of trusted components that are physically verified by their use in designs, and you learn the quirks and anamolies of the tools.

About 10 years ago, Protel ran a special and we purchased an upgrade seat of their flagship product at that time – Protel99SE. It was expensive – even when discounted, but we had had mostly good luck with their existing software and had a large investment in learning curves and libraries. The new product stayed on the shelf for several years with day-to-day pressures precluding taking on the new learning curve. Finally, frustrated with the PCB v2.8 tool’s problems with split power planes on a new 4-layer design, I moved the board to the new tool and was able to produce a product that we’re still shipping today. 

I recently did our second 4-layer PCB with Protel99SE SP6. Just received the prototypes back. When building the first board by hand, two components were on the schematic,  but not on the PCB. Bringing up the board in Protel and jumping to the component by name, the missing components were off the board, and off the screen – perhaps with a negative Y coordinate. No ratsnest wires, the router indicated that the board was 100% routed, no Design Rule Check (DRC) errors - sweet.

Did a select outside the board area, move selection, and surprise - the missing two components moved into the visible area - ratsnest wires appeared indicating where they were supposed to be connected and now the board is no longer 100% routed - it's magic !

I don't know how the two components got 'placed' off of the viewable screen, or why a zoom all didn't show them, or why the autorouter All Routes command didn't complain, or why the DRC passed...

I can no longer trust Protel99SE to produce a board that matches the schematic. This was a fundamental trust item that the tool violated with serious repercussions. I'm glad that these are just a handful of prototypes, and I can tack these two missing components on by hand. Imagine if I had made a simple change to a production board and then found missing parts and/or connections with 1000 of them in manufacturing.

Of course, this tool is now 10 years old. The company has changed it’s name – Altium – and has moved on. They are again offering a special purchase of an upgrade version…

And so it goes…