How to put a number into a word - RSLogix 500

wildcatherder · Oct 9, 2009

I know this is a simple question but, honestly, I have not been able to find the answer.

In DirectSoft there is a LD instruction by which one can put a constant into the accumulator and OUT it to a memory location.

I want to do the same thing in RSLogix but cannot figure it out. I've found all kinds of examples of complex counters, timers, sequencers, etc but this basic information does not seem to be online.

I'm looking for instructions compatible with Micrologix 1400

I will be getting a vast technical library on DVD from RockwellAutomation next week but in the meantime, I'm stuck.

SCADA_Dude · Oct 9, 2009

Mov t4:0.acc n7:0

SCADA_Dude · Oct 9, 2009

Timers have dot fields for accumulator, preset, enable, done etc

t4:0.acc (word)
t4.0.pre (word)
t4.0.en (bit)
t4.0.dn (bit)

wildcatherder · Oct 9, 2009

I'm sure that after 99 posts that is considered an example but I'm going to need something that looks like a ladder logic display so I can see which part of that is the number entered and which part is the word to which I am writing.

If I could write directly to the word, even better.

I have programmed several projects with DirectSoft but never in ASCII.

wildcatherder · Oct 9, 2009

I'm not talking about timers. I just need to get a number into a word so that I can manipulate it.

TConnolly · Oct 9, 2009

Scada dude, Don't confuse a timer .acc with the accumulator register used in other PLCs.

Wildcatherder, in the ML there is no need to load LD a value into the accumulator and then out it to a word. Just use a MOV instruction to move a constant to the address.

MOV 1234 N7:0.

However, if N7:0 will always have the same constant in it then just enter the value directly into N7:0 using the file editor in the programming software.

wildcatherder · Oct 9, 2009

Again, all very clear if you have done this before. Do you mean I can drag something called N7:0 onto the ladder logic? I don't think so.

wildcatherder · Oct 9, 2009

OK, in a sidebar window, which is labeled Untitled rather than something useful (maybe it is the File Editor?) under Project there is Controller, Program Files, Data Files, etc.

You suggest I open up N7 and "stuff" a number into a word in that window?

TConnolly · Oct 9, 2009

Here it is graphically.

In the AB PLC all memory is retentive so once you set a constant it will stay until you change it. You can also create files and designate them as static (constants) if you want. Click the properties button to set that feature, but refer to the manual for more information on it.

wildcatherder · Oct 9, 2009

Still can't see the attachment.

I am getting close to understanding. It's not because I'm lazy or unskilled. I've programmed in higher level languages and DirectSoft. The problem is that, at this level of (un)sophistication, all the things I am searching for on the forums and the web are "stop words": integer, word, load

TConnolly · Oct 9, 2009

You should see it now.

TConnolly · Oct 9, 2009

wildcatherder said:
OK, in a sidebar window, which is labeled Untitled rather than something useful...

Thats because you haven't saved your project file and given it a name yet. Save it and name it and you'll see that change.

bernie_carlton · Oct 9, 2009

The two step process in AD (LD, OUT) is one command in SLC500 (MOV). SOURCE can be a constant (just type a number) or a memory location which holds a value. DEST would be a memory location (possibly N7:??)

Most all the things which are single math manipulations in AB need several instructions in AD. One thing which may IRK you is when you want to do a series of manipulations but need to have a DESTination register for each command. If the CPT (Compute) instruction is available (processor dependenta) then by all means use it for chained operations.

But there are times when I really appreciate the ability to more finely manipulate the math accumulator in AD.

And Alaric - you circled LAD7 instead of N7 in your image. But I'm sure we get the idea.

wildcatherder · Oct 9, 2009

Thanks, the attachment just appeared when I reloaded the site.
This is exactly what I needed in the form I needed to see it.

I did open a sample project and the Project Name appeared instead of "Untitled". My point was instructions like "use the File Editor" are not a big help, if you have never opened the File Editor before.

That one picture was worth a thousand "hits". I do think you meant to circle the Data File "N7" rather than the Program File "LAD 7"

Thanks again.

TConnolly · Oct 9, 2009

D'oh.

By the way, posters often use mnemonic instructions and rungs in the forum because its easier and faster than creating a graphic.

When you see mnemonics typed in the forum, try this:

Open the mnemonic editor by double clicking on the rung number of a blank rung. Then paste in the code you see in the forum and press enter. Then you can see what it looks like graphically. This shows you what
ADD N7:0 N7:1 N7:2 will look like

How to put a number into a word - RSLogix 500

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