Front Panel Operation
2-106
Deviation is enabled through the CONFIGURE MATH
menu (see paragraph 2.18.7).
2.18.5 Ratio
The following calculation divides the normal display reading
by the user specified reference value:
where: X is the normal display reading
Y is the specified reference value
Ratio is enabled through the CONFIGURE MATH menu
(see paragraph 2.18.7).
2.18.6 Logarithmic
This calculation converts input readings to logarithmic base
10 values. The calculation is shown as follows:
log
10
X = Y
where: X is the input reading
Y is the logarithmic result
Example: Assume that exactly 1mA is being measured by the
Model 6517A.
log
10
1.000000mA = -3
Note that this calculation uses the absolute value of the nor-
mal input reading since you cannot compute the log of a neg-
ative number.
2.18.7 Selecting and configuring math
The polynomial, percent ratio, percent deviation or logarith-
mic calculation is selected and configured from the CON-
FIGURE MATH menu (see Table 2-28). The selected
calculation is enabled by pressing the MATH key (MATH
annunciator turns on). The Model 6517A then displays the
result of the calculation, using scientific notation where nec-
essary. The following display messages indicate which math
calculation is being used:
NONE
No calculation selected
POLY
Polynomial
%
Percent calculation selected
Ratio
X
Y
---
=
%DEV
Percent deviation calculation selected
DEV
Deviation calculation selected
RAT
Ratio calculation selected
LOG
Logarithmic calculation selected
Pressing MATH a second time disables the calculation.
NONE
With this menu item, no math operation goes into effect
when the MATH key is pressed. The MATH annunciator
lights, but NONE is displayed on the top line.
POLYNOMIAL
This menu item selects the polynomial calculation and al-
lows you to program the polynomial constants. The “a2”
constant is displayed first. You can retain the displayed value
or key in a new value. In either case, press ENTER to display
the “a1” constant. Retain or change this constant and press
ENTER to display the “a0” constant. If you change the “a0”
constant, be sure to again press ENTER.
PERCENT
This menu item selects the percent calculation and lets you
specify the target value. If you key in a new target value, be
sure to press ENTER.
Table 2-28
CONFIGURE MATH menu structure
Menu item
Description
None
Select no calculation when MATH
key is pressed.
Polynomial
Select polynomial calculation and
enter constants.
Percent
Select percent calculation and enter
target (reference) value.
%DEV
Select percent deviation calculation
and enter reference value.
DEVIATION
Select deviation calculation and enter
reference value.
Ratio
Select ratio calculation and enter ref-
erence value.
Log10
Select logarithmic base 10 calcula-
tion.
