Programming
Chapter 3
332
Figure 3.28
AF1
Standard Deviation Function Format After Execution
171615141312111076543210Bit No.
Word
Input 1
S
Result Address
Result
DE
11589
ER
Input 2
Input 3
Number of Inputs
0 0 3 200
201
202
203
305
306
(0)(0)(1)(0)
200
201
202
000
816
Data
Address
E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1 = Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (Set if number of inputs = 0)
Entry
and Display of Input and Result V
alues
Figure 3.29 shows one method you can use to enter values and display results of
an AF1 standard deviation function. Although there are several techniques for
accomplishing this, we chose the instructions. The first rung requests an AF1
standard deviation function. The top branch of the second rung shows the
number of values whose standard deviation is sought, 003, in word 200. it also
shows the three numbers involved in words 201, 202, and 203. The lower
branch of the second rung shows the resulting standard deviation as 000.816 in
words 305 and 306.
Error Message
If you insert a zero for the number of values whose standard deviation is sought,
the error bit (bit 14) is set and the result reads zero.
