Figure; Automatic Testing Sequences - Megger OTS 60AF Guia Del Usuario

Operation
When TIME / DATE is selected, a further sub menu is displayed as follows:
Scroll through and select as before.
DATE FORMAT offers the choice of U.K. date style (dd-mm-yy), or U.S. date style (mm/dd/yy).
Successive pressing of the SELECT key will select the alternate style.
To adjust the date, scroll to SET DATE, and press SELECT. Set the date with the left and centre arrow
keys, and press SELECT. Then set the month, followed by the day of the month, in the same way.
To adjust the time, scroll to SETTIME, and press SELECT. Set the hour with the left and centre arrow
keys, and press SELECT. Then set the minutes in the same way.
Selecting VIEW will display the time, together with date in the chosen format. To return to the sub menu,
scroll to highlight QUIT and press SELECT.
To return to the main menu, scroll to highlight MENU, and press SELECT.
Choose the appropriate pre-programmed oil testing specification programme from the main menu by
scrolling through using the
When a test specification has been selected in this way, the display screen changes to show the name of
the test (this remains in view throughout the test sequence) and gives an option to START the test
sequence with the left hand key, or return to the main menu with the right hand key. For each separate
test specification, the display will indicate appropriate choices of electrode shape and spacing, if the
specification stipulates these. The appropriate method of stirring is also shown. If the STIR MODE option
is displayed, the user may vary the mode of stirring between MAGNETIC (magnetic stirrer bar),
IMPELLER (stirrer test vessel), or NONE as is appropriate to the selected test.
When started, each test sequence is carried out completely automatically.
Note:- The microprocessor software contains routines which monitor the operation of the oil test set. In
the unlikely event of a problem occurring (whether caused by the test set or an external event),
the test currently in progress will, when resumed continue from the point at which the problem
occurred. If this is not possible the test set will be placed in a safe condition and a situation
status message will be displayed.
After an automatic test sequence is completed, the average is calculated from the following formula:
Average
Standard Deviation
The sample standard deviation s (also known as
Where s = sample standard deviation.
Data Dispersion
The ratio of standard deviation upon mean ( s / x ) also known as the co-efficient of variation is used to
determine whether the spread of a set of test results is within acceptable limits. This value may be
expressed as a percentage.
DATE FORMAT
VIEW
QUIT
SET DATE
SET TIME

Automatic Testing Sequences

, keys until the required specification is highlighted. Then press SELECT.
Calculations
i = n
1
x
x =
i
n
i = 1
i = n
s =
2
x - n x
i
i = 1
n - 1
x =
where
x =
i
n =
σ
) is given by:-
n-1
2
mean (average) of results
i th individual results
number of results