RS Logix: No unlatch Bit

[robertmee]

Thanks Ron....I learn something everyday!

I've almost never (to the point of purposely designing it) had to MOV, COP or FLL mixed data types, so I've never encountered that, but certainly good to know. If I have to do for example a MOV of N to F, I'll do a CPT instead of N * 1.0. Just an old practice and it avoids the issues you correctly bring up.

 

[Ron Beaufort]

for those who emailed (and/or phoned) and couldn't stand the suspense:

21845 at N7:10 is the binary pattern 0101010101010101
-21846 at N7:11 is the binary pattern 1010101010101010

B3/0 makes F8:0 = 1.468306e+13

and that loads "getting started" patterns into the "Source"

-----------------------------------------------------------

now then ...

B3/1 (MOV) makes N7:0 = -1
B3/2 (COP) makes N7:0 = 21845
B3/3 (FLL) makes N7:0 = -21846

key point: the MOV, the COP, and FLL don't have the same effect on the destination ...

survival tip: don't worry about it ... but ... if you start running into "weird" problems, try to remember that you saw it first here - on Phil's excellent forum ...

PS Edit: Greetings Robert ... I often get accused of dredging up stuff like this just to torture people ... but with VERY few exceptions, exercises like this come DIRECTLY from helping debug programs in the field ... so ... where in NC? ... my wife is from near Spivey's Corner - Hollering Capital of the Universe ...

 

[robertmee]

PS Edit: Greetings Robert ... I often get accused of dredging up stuff like this just to torture people ... but with VERY few exceptions, exercises like this come DIRECTLY from helping debug programs in the field ... so ... where in NC? ... my wife is from near Spivey's Corner - Hollering Capital of the Universe ...

I'm in Apex (15 miles SouthWest of Raleigh near Jordan Lake). I've driven through Spivey's Corner but never attended the hollering contests. You married a good woman if she's from NC

 

[Clay B.]

I'm in Apex (15 miles SouthWest of Raleigh near Jordan Lake). I've driven through Spivey's Corner but never attended the hollering contests. You married a good woman if she's from NC

Well I have married 2 women from NC so I would say it is a 50/50 shot....

 

[geniusintraining]

Well I have married 2 women from NC so I would say it is a 50/50 shot....

LOL...... very very funny

 

[OkiePC]

Thanks Ron....I learn something everyday!

Ain't he great?

I've almost never (to the point of purposely designing it) had to MOV, COP or FLL mixed data types, so I've never encountered that, but certainly good to know.

You may find that type of logic used to interface 3rd party devices, and even some A/B drives like the Ultra servos with serial connection. Sometimes a bit for bit COPy and a byte swapping routine are necessary to interface data types from external processors.

If I have to do for example a MOV of N to F, I'll do a CPT instead of N * 1.0. Just an old practice and it avoids the issues you correctly bring up.

"Type casting" is the term for that I think.

Paul

 

[bmw_apprentice]

ah thats interesting. all this information is so interesting. stuff you wouldnt think of. im sure one day in the long and distant future ill be pulling my hair out and ill think of this forum...i wish i could just configure my brain to let me download this all into my head........

 

[bmw_apprentice]

the MOV function faults out my processor. the value is too high i think. should this happen???