HPR4718: Programmable Logic Controls - Episode 2

Hosted by Whiskeyjack on 2026-09-02 01:00:00

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Antoine says: PC meaning

RE: hpr4718::2026-09-02 Programmable Logic Controls - Episode 2 by Whiskeyjack
00:30:54 Listen in ogg, opus, or mp3 format.
Me listening: 'PC stands for' (Personal Computer) 'Programmable Controller". (Mind blows.)
'It also came to mean Personal Computer'. Uff, I was not ALL wrong after all.

I haven't listened to all the PLC series for now, but what I listened to is very well done.

What I saw in ep. 3 (hpr4728) and caught my attention is that the memory management was manual, so the programmer needed to know and define the adresses for the functions (for that specific PLC), and this episode 2 conveys a similar ideia: inputs and outputs are not figures on their own to referentiate: you need to go to their memory adresses to get them.

I was thinking if it was an advantage, as to simplicity or precision or maybe even security (as to be so low-level that it was hard to do something wrong that still would worked in unintended ways, instead of just not working), or if it was mere limitation of the processing capacity and languages (not) supported at the time.

Don't see this as a question, it probably is self-answered in the shows and I just have to listen more of them calmly. See as an attention-grabbing content.

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Whiskeyjack says: Reply to Antoine on memory addresses

RE: hpr4718::2026-09-02 Programmable Logic Controls - Episode 2 by Whiskeyjack
00:30:54 Listen in ogg, opus, or mp3 format.
In the series on PLCs I stuck mainly to older systems as they are simpler and so can be more easily explained in a podcast.

Some later PLCs used their programming software (or IDE) to add layers of abstraction to addressing which could be seen as the equivalent of named variables as opposed to address based.

Manual memory assignment was not actually that difficult in practice, but your point of view on that may depend on the size and complexity of projects that you worked on.

There is much to be said for simple PLCs and programming software when your objective is to bang out small projects quickly without having to become an expert in many different brands of different proprietary PLCs.

So, your point of view on this can vary depending on what sort of projects you worked on.

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