RSlogix 5000

[muusic_man]

I've seen several examples of averaging a number on here, but can't get any to work right for me.

I have a real number from a pressure transmitter.
I want to take 1 sample per second
a total of 5 samples
Average and send to an word that is then displayed on my HMI

I see an AVE command and I tried to use it but I don't understand how the "control" value works.

Any specific help would be greatly appreciated.

Thanks in advance.

 

[rleon]

The Conrol value is a CONTROL Data Type. You have to create that tag and set the values of Len (number of elements to average, in your case 5) and POS (position of the array where the average starts, in ypour case 0)
For your example you can create an array of 5 DINT( DINT[4]), a tag REAL to use as dest, a Control tag and set the "Dim to vary" to 0.

For the sample per second you can create a periodic task of 1 second to fill the array with some insruction like FOR and n=n+1 position, in structured text.

Then, with the array complete the AVE function (in another task) will be calculating the average of the actual values in the array, that will be changing every 1 second.

 

[(8{)} ( .)]

Hope I'm not being obtuse here but since you've got such a small

set of data why not totalize the value once per second for five

seconds and then divide it by 5. No control words, special

function, or anything else. Just really simple math.



Good luck

(8{)} .)

(Yosi)

 

[muusic_man]

Thanks guys, I got it and it looks good. I had just never used anything requiring control but I understand it now.

 

[Phreakadelika]

RSLOGIX 5000 Symbol

WEll im new in PLCS.net and im here cause i need help and ill help to answer questions 2 ...!

In Rslogix 5000 im trying this in structured text

Y2:= 1.0/ (1.0 + EXP(-ENT[I,2]*(VAR_EN - ENT[I,3])));

but the exp doesnt recognize its the e(x) operation ... i tried ...e((-ENT[I,2]*(VAR_EN - ENT[I,3]))); ...
...E((....
Its not XPY of course...

Well i hope somebody knows thank you

 

[TConnolly]

Try using the double asterisk, e**x.
e is not a predefined variable or language element, so you will have to use 2.718281828**x

 

[Phreakadelika]

wee

Thanks a lot I just set EXP = 2.71.... and use double **

Y1:= 1.0/ (1.0 + EXP**(-ENT[I,0]*(VAR_EN - ENT[I,1])));