Quick RSLogix 500 question

[geniusintraining]

Thanks for the good info Ron

 

[Operaghost]

Ok Ron, I don't see the error. This makes sense for a count down style counter. What am I missing? The only thing I see that could be wrong with that statement is that an "underflow" condition would prevent the countdown (CTD) from resetting the done bit until the underflow condition was corrected (possily by an overflow).

.............
and so ... Counters ... after all, just how complicated can these little things be? ... well, sometimes they can even confuse the people who write the official books ... take this statement (copied verbatim) right from page 3-8 [Adobe Reader page 51 of 169] of the official 1785 PLC-5 Programmable Controllers Quick Reference manual (publication 1785-7.1, dated May 1999) on the official Allen-Bradley website ...

can you spot the error? ... yes, we’re all human ... even the people who write the official PLC books ...

Which brings up another method or restting. If a counter overflows by counting up and crossing 32767 and starts heading negative then a count down will clear the overflow and bring you back into positive and could eventually cross below your preset, restting the DN. Only problem there is that you could roll over five times and only one underflow would be needed to reset the OV. Thank goodness we can count higher in the CLX.

OG

 

[geniusintraining]

Ok Ron, I don't see the error. This makes sense for a count down style counter. What am I missing? The only thing I see that could be wrong with that statement is that an "underflow" condition would prevent the countdown (CTD) from resetting the done bit until the underflow condition was corrected (possily by an overflow).
OG

It was at the bottom of Ron's lesson

I actuality got that one correct

I’m 1 for 1 on the "Ron quiz"... next ?? This is better the RS classes

Ron on your web site I see level 1 and 2 in the AB SLC 500, do you offer level 3 or would this be part of the custom class? if so can you send info on what it would cover

Thanks

 

[jedft]

Greetings to all ...



well, I don’t know about you guys, but I just LOVE a thread that starts off as a “Quick Question” and then runs on for umpteen posts ...

HAHA In defense of my subject line, my particular question was answered long ago

I'm not saying stop however... I'm learning a lot here!

 

[Ron Beaufort]

as geniusintraining has pointed out, the answer to my little “what’s-wrong-with-this-picture?” quiz is contained in the “answer.txt” file attachment at the bottom of post #15 ...



and from geniusintraining:

Ron on your web site I see level 1 and 2 in the AB SLC 500, do you offer level 3 or would this be part of the custom class? if so can you send info on what it would cover

since you asked, I’ll answer ... it would be a “roll-your-own” custom class - but send me a PM with your e-mail address and I’ll be glad to send you the information you asked for ... if I post the stuff here, it’s going to start sounding too much like advertising ... as for finding anything on the company website, I’m sorry but it’s a wreck right now ... our guys moved the server across town the other day and apparently it didn’t like the change in scenery ... we’re limping along on an older backup unit until someone gets time to fix things up ... Tim, our local computer genius, is tied up out-of-town on a tight-deadline ControlLogix project right now ... hopefully he’ll be available soon to get things back in order ... in the meantime, I can’t even update the schedule ...



and from jedft:

I'm not saying stop however... I'm learning a lot here!

and that’s what the forum is all about ... thanks, as always, to Phil ...

 

[MisInformed]

Ron

Thanks for solving a problem I've had for awhile now with some of my CTU's! It's been driving me nuts for about 2 years now as to why on some CTU's I get a false count when I reset them and on others I don't. You made it seem so easy I have to wonder how I missed the rung being true in front of the counter when the reset command was given. I'm going to have to make it part of my routine to add that OSR before the CTU from now on.

Thanks!!