STEP file, which viewer?

How can you do sensiblly annotated multichannel design without hierarchy in the schematic?

Or do you consider that a special acceptable case?

--sp

If there are 48 channels, all 48 channels appear on the schematic. Nice and flat. Every net has a unique net name, and every part has a unique refdes, which is handy.

What do you mean by "sensibly annotated"?

Parts have ref designators on the schematic and the board. Last part of the layout, they are geometrically resequenced on the PCB for ease of physical location, and back annotated to the schematic.

Seems to work.

Yikes. That's why there are no trees left around San Francisco :-)

I use something like R70A R70B R70C for the part that does the same thing in Channel A, Channel B, Channel C. Altium accomodates that, automatically though their default is something more general, much longer and much less desirable for small numbers of channels.

Of course my favorite scheme runs out of gas at Channel Zed (26), but so far it's been enough.

--sp

R70A through R70D are sections ("gates" to PADS) of a 1206 quad resistor pack!.

The gadget in layout now has 48 channels of isolated digital inputs, with amazingly clever front-end self-test. The schematic is 19 sheets. The way things are partitioned, a true hierarchical design would be messy and (to my tiny mind) confusing.

A 16-channel thermocouple simulator module ran to 24 sheets, half of which are the channels. If the channels were blocks, each would have the i/o connector pins, power supplies, FPGA pins, test bus, and a few more things sticking out of each block. Mysterious albino porcupines.

That's all still fairly low channel numbers. The biggest schematic I had to deal with was a 256-channel system where the channels were busy analog circuits. You could have crammed two onto a page if resorting to Japanese-style circuit drawings but even that would have been 128 sheets. Instead, we had only one for all those channel sections and it was nice and spacious. The rest of the board was another couple dozen or so sheets.

Some of the reviews clients want me to do would be next to impossible without a hierarchical set of schematics.

Sometimes. Not always. There's often other reasons not to renumber. "Always" rules always get in the way.

Ick. How do you guarantee that any changes make it into all 48?

Hierarchy doesn't preclude any of the above, in any way.

Except when it doesn't.

"Sometimes" rules aren't rules!

We check things, like on all the other sheets of the schematic.

The vast majority of our first articles, Rev A, work and can be sold. We don't prototype.

On this 48 channel thing, we share some parts between channels, like some optoisolators and some pulse transformers. If the top level sch had a block per channel, how would you share those parts? Pull them out of the blocks?

Seems to work. I can't recall a case where we changed some channels but forgot to change others.

Nah, put a grouping property in your opto, then descend into each page of your yeahrarchy and set the group property accordingly. That's all.