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Search: Posts Made By: drbitboy
Forum: LIVE PLC Questions And Answers Today, 08:54 AM
Replies: 4
Views: 182
Posted By drbitboy
@glencovington and @MikeyN got there first, but I...

@glencovington and @MikeyN got there first, but I will try to state it in a different way.

I supect you are reading that logic asStart pump if ... AND (level is above 24cm)
but another way of...
Forum: LIVE PLC Questions And Answers Yesterday, 02:31 PM
Replies: 16
Views: 687
Posted By drbitboy
[Update: whoops, maybe I misinterpreted what...

[Update: whoops, maybe I misinterpreted what "It" referred to: ramp rate or mean scan time?]


***MEAN*** scan time, to within a few percent, I suspect it is. And that may be enough for this...
Forum: LIVE PLC Questions And Answers Yesterday, 01:58 PM
Replies: 16
Views: 687
Posted By drbitboy
mean scan time is reasonably constant, and can be...

mean scan time is reasonably constant, and can be calibrated every few minutes.

So why not use a count of scans as a pseudo-free-running clock? Is the ramp rate that critical?
Forum: LIVE PLC Questions And Answers Yesterday, 01:12 PM
Replies: 22
Views: 609
Posted By drbitboy
Actually that may not be necessary, as long as...

Actually that may not be necessary, as long as multiplied-by-10/ADD 0.5/TRN values and limits are compared in the first place.
Forum: LIVE PLC Questions And Answers Yesterday, 01:01 PM
Replies: 22
Views: 609
Posted By drbitboy
If they fail, add or subtract 0.1, then send to...

If they fail, add or subtract 0.1, then send to DB.


update: I think my method, which ADDs 0.5 and TRNs after MULtiplying by 10, and does the pass-fail test before the DIV, ensures any failed...
Forum: LIVE PLC Questions And Answers Yesterday, 12:26 PM
Replies: 22
Views: 609
Posted By drbitboy
Yes, it is safe to divide by 10 for storing the...

Yes, it is safe to divide by 10 for storing the value in the DB, but don't use it for the compare. Caveat: that may put values in DB that appear to pass or fail when the stored pass/fail value...
Forum: LIVE PLC Questions And Answers Yesterday, 11:39 AM
Replies: 116
Views: 8,116
Posted By drbitboy
Yes, the scanner itself adds the CR, and by...

Yes, the scanner itself adds the CR, and by default, if I remember the documentation correctly.

So a CR will, usually I assume, will be followed by a pause (the scanner has an...
Forum: LIVE PLC Questions And Answers Yesterday, 10:47 AM
Replies: 22
Views: 609
Posted By drbitboy
Yes; comparing non-integral values of REALs...

Yes; comparing non-integral values of REALs should be avoided. Do this instead:MULtiply by 10
ADD 0.5 (Note 1)
TRN
LIM/LES/LEQ/GEQ/GRT (Notes 2 & 3)
Notes


Assumes positive values
Do...
Forum: LIVE PLC Questions And Answers Yesterday, 10:30 AM
Replies: 16
Views: 687
Posted By drbitboy
That is I-only control; Integral-only; no...

That is I-only control; Integral-only; no P/Proportional or D/Derivative.

I am not saying it won't work, just sayin' ...

I assume there is, though not shown,


something in there to...
Forum: LIVE PLC Questions And Answers Yesterday, 08:37 AM
Replies: 116
Views: 8,116
Posted By drbitboy
I think the carriage return, that is already the...

I think the carriage return, that is already the suffix/terminator, is all that should be needed.
Forum: LIVE PLC Questions And Answers October 23rd, 2021, 03:32 PM
Replies: 49
Views: 2,687
Posted By drbitboy
Whoops, that will only work with total integer...

Whoops, that will only work with total integer gram values (#yigit) greater than -3. There are two ways to implement MOD, and apparently Siemens chose to implement it wrong mathematically; it is not...
Forum: LIVE PLC Questions And Answers October 23rd, 2021, 03:11 PM
Replies: 12
Views: 1,014
Posted By drbitboy
In California, one to change it and two to relate...

In California, one to change it and two to relate to the experience.


In Oregon, one to change it, and three to chase away the Californians who came up to relate to the experience.
Forum: LIVE PLC Questions And Answers October 23rd, 2021, 08:56 AM
Replies: 49
Views: 2,687
Posted By drbitboy
Change Network 4 to this:CONV(Int to Real) #yigit...

Change Network 4 to this:CONV(Int to Real) #yigit #adam DIV(Real) #adam 5.0 #salak ROUND(Real to Real) #salak #salak DIV(Real) #salak 200.0 #salak
Update: fixed typo

But better to not use the...
Forum: LIVE PLC Questions And Answers October 22nd, 2021, 05:50 PM
Replies: 116
Views: 8,116
Posted By drbitboy
It's a few posts back: ...

It's a few posts back: https://www.plctalk.net/qanda/showthread.php?p=895784#post895784


I think I also implemented that method, untested of course: ...
Forum: LIVE PLC Questions And Answers October 22nd, 2021, 02:41 PM
Replies: 116
Views: 8,116
Posted By drbitboy
This should fix the...

This should fix the two-lights-on-at-the-same-time issue.59840
That 251-byte read *might* work, but I expect the most robust algorithm will be the one suggested in the Horner video i.e. wait for a...
Forum: LIVE PLC Questions And Answers October 22nd, 2021, 12:47 PM
Replies: 7
Views: 458
Posted By drbitboy
(a MOD b) = 1 ? Although that...

(a MOD b) = 1


?


Although that would also return true for a := N*b + 1, when N is an integer.
Forum: LIVE PLC Questions And Answers October 21st, 2021, 10:28 PM
Replies: 2
Views: 292
Posted By drbitboy
We need more information to be able to offer...

We need more information to be able to offer useful help.

What make and model are the [system 1] and [DCS] devices? Can you provide PDF manuals for the devices?

Which system initiates the...
Forum: LIVE PLC Questions And Answers October 21st, 2021, 02:04 PM
Replies: 49
Views: 2,687
Posted By drbitboy
Whoops, right, thanks, I was thinking FLOOR...

Whoops, right, thanks, I was thinking FLOOR (round toward -Inf) not TRUNC (round toward 0).


Negative weight is problematic anyway, as you note.
Forum: LIVE PLC Questions And Answers October 21st, 2021, 12:48 PM
Replies: 49
Views: 2,687
Posted By drbitboy
If #silly is a real e.g. with a value of...

If #silly is a real e.g. with a value of 1.65:TRUNC(Real to Dint) #silly #silly_dint_kg
CONV(Dint to Real) #silly_dint_kg #silly_real_kg
SUB(Real) #silly #silly_real_kg #silly_real_kgfrac...
Forum: LIVE PLC Questions And Answers October 20th, 2021, 10:26 PM
Replies: 11
Views: 929
Posted By drbitboy
<Yoda voice> Help does this: ...

<Yoda voice> Help does this:

https://cache.industry.siemens.com/dl/files/814/109751814/att_933093/v1/STEP_7_-_Statement_List_for_S7-300_and_S7-400.pdf...
Forum: LIVE PLC Questions And Answers October 19th, 2021, 01:59 AM
Replies: 5
Views: 473
Posted By drbitboy
You want a data UNION in structured text cf....

You want a data UNION in structured text cf. http://www.plctalk.net/qanda/showthread.php?t=119300 or https://help.codesys.com/webapp/_cds_datatype_union;product=codesys;version=3.5.12.0


So you...
Forum: LIVE PLC Questions And Answers October 18th, 2021, 08:27 PM
Replies: 5
Views: 473
Posted By drbitboy
I assume you have two 16-bit integers and and...

I assume you have two 16-bit integers and and want to reconstruct the 32-bit real their bit pattern represents.

There is a mathematical approach, using bit-wise ANDs and floating-point DIVides and...
Forum: LIVE PLC Questions And Answers October 18th, 2021, 03:57 PM
Replies: 11
Views: 929
Posted By drbitboy
Also note that, if OP's original interpretaion...

Also note that, if OP's original interpretaion was correct, and if #MaxPos is less than #MinPos, then routine [N1Lo] can never be executed.
Forum: LIVE PLC Questions And Answers October 18th, 2021, 02:27 PM
Replies: 11
Views: 929
Posted By drbitboy
https://support.industry.siemens.com/cs/document/4...

https://support.industry.siemens.com/cs/document/45523446/simatic-step-7-v5-5-statement-list-(stl)-for-s7-300-and-s7-400-programming?dti=0&lc=en-WW


I think OP's interpretation might be...
Forum: LIVE PLC Questions And Answers October 18th, 2021, 02:08 PM
Replies: 18
Views: 1,142
Posted By drbitboy
Actually, I think I used the wrong terminology...

Actually, I think I used the wrong terminology with regard to my situation (SOHO to SOHO): the VPN may route through the cloud, but the VPN server is behind one of the routers. As @ArcReactorKC...
Showing results 1 to 25 of 500

 
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