Hex-Digits
All 12 digits together represent register 3.
When the digits are divided into two groups, the first six
digits represents register 1 and the last six digits repre-
sent register 2.
Formula
Depending on the selected measuring function different
calculations must be made to convert the register con-
tents to readable measuring results.
The first letter (F) in the output data indicates which for-
mula you must use.
If ’F’= Use this formula
C
Reg
. 2 ∗ 10
7
Reg
. 1
F
Reg
. 3
G
Reg
. 2
Reg
. 1
I
Reg
. 1 ∗ 10
−7
Reg
. 2
J
Reg
. 3 ∗ 10
−7
K
Reg
. 2 ∗ 10
−7
Reg
. 1
Multiplier
The second letter (M) in the output data represents a
multiplier which you must multiply the results by before
presenting it.
If ’M’= Multiply results by:
H60
L256
N0.1
O10
P1
EXAMPLE 1:
The following HP-85 program sets up a High-Speed
dump Single-period measurement.
OUTPUT 710;"PER A,MTIME 0"
ENTER 710;A$
A$
PER 000001.667E-4
OUTPUT 710;OUTM 4
ENTER 710;A$
A$
JP000000000683
’J’ means that you must use formula J which is:
Reg
. 3 ∗ 10
−7
000000000683 is the hex-contents of register 3. The reg-
ister contents must be converted to a decimal number
and entered in the formula;
683
Hex
= 6 ∗ 16
2
+ 8 ∗ 16 + 3 = 1667
decimall
The result is 1667
*
10
-7
. which you must multiply by "Mul-
tiplier P", which is 1, to get the measuring result.
1667
∗ 10
−7
∗ 1 = 1.667 ∗ 10
−4
s
= 166.7 µ
s
EXAMPLE 2:
The following HP-85 program sets up a High-Speed
dump Frequency A measurement with 1 s Measuring-
time.
OUTPUT 710;"FREQ A,MTIME 1"
ENTER 710;A$
A$
FREQ 006.000006E3
OUTPUT 710;OUTM 4
ENTER 710;A$
A$
CO98555B000257
Formula ’C’ is:
Reg
. 2 ∗ 10
7
Reg
. 1
98555B is the hex-contents of register 1, and 000257 is the
hex-contents of register 2. Both register contents must be
converted to decimal numbers and put into the formula;
(2 ∗ 16
2
+ 5 ∗ 16 + 7) ∗ 10
7
9 ∗ 16
5
+ 8 ∗ 16
4
+ 5 ∗ 16
3
+ 5 ∗ 16
2
+ 5 ∗ 16 + 11
=
= 600.0006209..
This number is multiplied by multiplier ’O’ to get the
measuring result:
600.0006209 ∗ 10 = 6000.006209 = 6.000006209 ∗ 10
3
Hz
How Many Digits are Significant?
Select the formula for ’LSD displayed’ in the ’Specifica-
tions’. There are different formulas for different measure-
ments.
Frequency:
LSDdisplayed
:
2.5
∗10
−7
∗
FREQ
Measuring
−
time
LSDdisplayed
:
2.5
∗10
−7
∗ 6000....
1
= 0.0015
LSD = 0.001 Hz
The result is 6.000006
*10
3
Hz
111111222222 =
= 333333333333
MSB LSB
MSB LSB
111111 222222
MSB LSB
GPIB-INTERFACE OPERATION Page: 29
PM 6669 - OPERATORS MANUAL
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