Greetings! Long term PLC guy with experience in several brands - mostly A-B though - experimenting with a Logo for the first time. Being new to their approach I'm finding navigating the Siemens manuals and support sites a bit challenging.

I understand the Logo is targeted more to be configured than programmed, but I am curious how it compares to more full function PLC's.

Can the data be accessed as one would with normal tags in an S7 or A-B Logix controller?

On a related note can you access bits within a DINT or other data type?

Is there a concise breakdown of the various data types available in the Logo! Settings//Offline Settings//I/O Names such as X, NQ, NA, M and so on?

Thanks!

ixo65, Thank you for the prompt reply, and you are correct - I should have mentioned the version - sloppy of me - but it is v8.3. I had viewed some of the web links you'd sent prior to posting, but I will go through them again.

However, I'm not really looking for years of distilled knowledge to be summarized in three sentences. As I attempted to explain - perhaps badly - my focus is trying to understand the tag naming and data handling capabilities of the Logo. I'm happy to muscle my way though the rest, but again, I'm not having much luck finding references to data types and the like in Logo, which makes me wonder if it has none beyond how the blocks define their members/structures. You mentioning it is a 16 bit machine is a good starting point. Please allow me to elaborate further to see if we can find a point of common understanding.

If I declare a tag in an S7 or ControlLogix, I can then define when data type it is. For example were I to call the tag "Level" I then define as a DINT or INT or BOOL, and so on. To take that a step further, should I choose DINT, the tag LEVEL could then be a single DINT, or an array of DINTs. I can use the tag as is for DINT 32 bit values, or if I wanted to reference the fourth bit in a single DINT tag, the address would be LEVEL.3, or if I had defined it as an array and I wanted the third element in the array it would be LEVEL[2], or the fourth bit in the third word the tag would be LEVEL[2].4 (all assuming zero inclusive number schemes of course).

I've attached the dialog where I/O names are defined. If I could find a simple primer to describe what each of the various options are there it would be a very good start. For example I and Q are quite obvious, but X, NA, NAQ AM and so on less so. I'm a little surprised that context sensitive help wouldn't provide that information concisely in one place, but perhaps it is considered such common knowledge they didn't bother?

As a bit more backstory beyond just learning the platform for the sake of learning, the application in this instance is to log a series of analog values from a single input so I can slice and dice that data afterwards as well as control/monitor the process in real time. It may will be that in the end it will turn out I need to adapt my data centric thinking to the limitations of the Logo platform. Old dogs, new tricks. ;->