3 ms·
I don't fully agree either, but some of them make sense. But, some of them do make enough sense for some kind of critical applications, that it is worth to cons
by zzo38computer 2y ago
I don't fully agree either, but some of them make sense. But, some of them do make enough sense for some kind of critical applications, that it is worth to consider the alternatives (although power usage should also be considered).
As items (iii) (although it incorrectly says "(ii)") and (iv) of the caption of figure 1, are reasonable considerations.
There is also the consideration of faulty displays, in case a segment stops working (although you can mitigate this problem somewhat, by adding a test switch to light up all of the segments).
About decimals, one possibility (depending on the application) is to require a fixed position for the decimal point and add a wider gap between the digits at that position, which improves the clarity.
They also mention, "the user cannot see the difference between entering zero, or entering zero then decimal point". This is a problem on many hand-held calculators but it is easy to avoid, by not displaying the decimal point unless it has been entered explicitly (or if the result is being displayed).
Upsidedown (also mentioned in the article) is also a reasonable consideration, although there are ways to mitigate that too.
- throwway120385 2y agoIn the event that you need to test the display, you should just periodically light up all the segments briefly.
- pclmulqdq 2y agoThis happens on startup for many critical systems. They turn every segment on and they turn every segment off.
- jtriangle 2y agoUsually when these displays initialize they turn on every segment before displaying data for that reason. Also, fairly trivial to detect if a display has a segment out and throw a fault if needed. It's also not likely you burn out a whole segment at once if you have it wired up with that in mind.
- crote 2y agoIf anything, 7-segment displays are better when it comes to partial failure, as it's reasonably easy to add self-test functionality which measures the current passing through a supposed-to-be-lit / supposed-to-be-off segment. This would allow for failure detection without the user having to explicitly press a test button and look for any misbehaving segments. You can't do this as easily (if at all) with LCD or OLED.