integer value = bits on

[Doug-P]

Re: Doug P, you will scare away the rookies.

Only the timid ones!

 

[Jnelson]

Doug,

That is not what I meant, although it was valuable information. What I was talking about is what Peter entered in his post #29. I was simply curious how the soure would be entered into the move instruction, in this case N9:[N7:0]. Thanks Peter for the example, and Doug for the help.

 

[Eric Nelson]

The # simply indicates that this is an 'indexed' address (rather than a direct address). It would be entered exactly as shown... #N9:[N7:0]. Here's a blurb from the Help file:
[attachment]
Note: Indexed addressing is not available in the ML1200/1500. Here's a clip from an old post of mine:

• Though you can't use indexed addressing (i.e. #N7:50) with the ML1200 and 1500, you CAN use a register (let's use N7:50) to point to an offset (indirect addressing). For the value, you use brackets "[]" around the register containing the offset value. So, if the value of N7:50 is 41, and you use N7:[N7:50], this actually points to N7:41. Confused yet? It's kinda simple once you figure it out...

beerchug

-Eric

 

[elevmike]

Eric:

As you know, I'm not famillar with the AB but heres a possable workaround if an instruction for indirect addressing is not available.

Pointers without the use of a pointer insturction:

A long time ago, before I wised up and read the ADC manual, I created a pointer by INC or DEC a memory location, to hold my pointer. I then used comparitave contacts drive an output to read the data in that actual data location.

V2000 is the pointer.

   X0

---||---------|INC V2000|



   X1

---||---------|DEC V2000|



   WHAT EVER

----||---------------------------MLS (MCS)



---|V2000|=|K1|----------------|LD data 1|

                                    

---|V2000|=|K2|----------------|LD data 2|



---|V2000|=|K3|----------------|LD data 3|



AND SO ON....



--------------------------------MLR (MCR)

    what ever

-----||--------------------|OUT -WHEREEVER|

P.S.
This only applies if this is what you guys are talking about...
(I have not read the entire thread)

 

[Eric Nelson]

Mike, I understand what you're taking about, but try not to confuse the 'AB only' guys with all that V2000, X1, INC, DEC, and LD stuff...

beerchug

-Eric

 

[Peter Nachtwey]

Don't make a simple thing hard.

elevmike, why not use the LDX instruction? AD has a pretty simple and efficient way of doing indexed addressing. See section 5-61 of the AD manual.

 

[Eric Nelson]

I think you missed the "A long time ago, before I wised up and read the ADC manual" part, Peter...

beerchug

-Eric

 

[Mike 61131-3]

This doesn't help much for an AB processor, or many of the others for that matter. If your programming tool supported all IEC 61131 languages then it could be accomplished simply with:

any_word:=REAL_TO_INT(EXPT(2,n)-1);

in structured text language.

I tested this in a WAGO controller and it works great!

 

[Peter Nachtwey]

Just because you can doesn't mean you should.

So

any_word:=REAL_TO_INT(EXPT(2,n)-1);

works. One should avoid exponenets and floating point whenever possible. Use

any_word:=SHL(1,n)-1;

instead. This can be many hundreds of times faster if the CPU does not have a hardware floating point unit.