User Manual

6
42- 44 6
00
43-43,33 00
REGISTERS
n: Unused i: Unused
PV: Unused PMT: Unused
FV: Unused
R
0
: α
R
1
: 1 - α
R
2
: S
t-1
R
3
: T
t-1
R
4
: Σe
2
R
5
: D
t
R
6
:
t+1
R
7
-R
.4
: Unused
Selecting the "best" smoothing constant (α):
1. Key in the program and press CLEAR .
2. Key in the number 1 and press
.
3. Key in the "trial
α
" and press
0 1.
4. Key in the first historical value (X
1
) and press 2.
5. Key in the second historical value (X
2
) and press 6 . The result is the error
between the forecast value (
t+1
) and the true value (X
t+1
)
6. Press
; the display shows the next forecast (
t+2
).
7. Optional: Press
5 to display the smoothed estimate of current demand.
8. Continue steps 5 and 6 for X
3
, X
4
, ... X
n
until all historical values have been entered.
When doing step 5 merely key in the value and press
(do not press 6).
9. Press
4. This value represents the cumulative forecasting error (
Σ
e
2
). Record the
value and the following additional values; press
0 (
α
), 2 (smoothed average
S
t-1
), 3 (trend T
t-1)
and 6 (forecast
t+1
).
10. Press
CLEAR .
11. Repeat steps 2 through 10 until a "best"
α
is selected based on the lowest cumulative
forecasting error (Register 4).
Forecasting: