Rockwell Automation 1772-AF1,D17726.5.1 User Manual MINI-PLC-2/15 - Manual (Page 38)

Programming
Chapter 3
3Ć30
Figure 3.26
General AF1 Standard Deviation Function Word and Digit Format
17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0
S
Digit 1
(MSD)
Digit 2
Digit 3
Bit No.
Data Address
Digit 2
Input 1
S Digit 2 Digit 3
Digit 2 Digit 3 Digit 1
S
Digit 1
(MSD)
Digit 2 Digit 3
Result Address
Digit 5 Digit 4
Result
D E
E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
MSD = Most Significant Digit
LSD = Least Significant Digit
11588
Digit 6
ER
ER = Error Bit (Set if number of readings = 0)
S
S
(LSD)
Digit 1
(LSD)
Input 2
Input 3
Input N
m
m + 1
m + 2
m + 3
m + N
n
n + 1
N = Number of Readings Whose Standard Deviation is Sought
Number of Inputs
Digit 1 Digit 3
Digit 2 Digit 3 Digit 1
3. Enter a data address and store in that address the number of values whose
standard deviation you wish to determine.
Let’s choose a data address of 200 and the number of values whose standard
deviation we want of 003. Also, let’s choose 305 as our result address.
Entering these values results in the data table format shown in Figure 3.27.
once you enter the data address, the addresses of the remaining input words are
selected automatically by the AF1.