22
The number of break-points required should first
be entered using the 'Add' and 'dEL' functions. In
both these functions the indicator initially displays
the current break-point and the total number of
break-points being used. e.g.
5 13
current total number of
break-point break-points
Display Description of function
'Add'
Add a break-point
Adds a new break-point before the
displayed break-point. The calibration
of existing break-points is not changed,
but the identification number of all
subsequent break-points is increased
by one.
'dEL'
Remove a break-point
Removes the displayed break-point
and joins the preceding break-point to
the following break-point with a straight
line. The identification number of all
subsequent break-points is decreased
by one.
To add a break-point select 'CAL' from the main
menu and press
P
to enter the 'Add' function;
press
P
again to reveal the current and total
number of break-points. Each subsequent
operation of the
P
push-button will introduce an
additional break-point. When adding a break-point
to a calibrated indicator, the insertion position can
be selected using the
Up
and
Down
push-buttons.
The delete break-point function 'dEL' operates in a
similar manner to the 'Add' function described
above.
When the required number of break-points has
been entered, return to the sub-menu by pressing
E.
The indicator will display 'Add' or 'dEL'
depending upon the last function used. Each
break-point can now be programmed.
Select 'PtS' from the sub-menu and press
P
which
will select the first break-point '0 n', where n is the
total number of break-points entered. The
selected break-point can be changed using the
Up
and
Down
buttons. When the required break-point
has been selected press
P
. Set the indicator input
current to the exact value at which the break-point
is to occur, and adjust the indicator display using
the
Up
and
Down
buttons and
P
to move between
digits.
When the required display has been set, press
E
to enter the information and return to the sub-menu
from which another break-point can be selected.
Repeat this procedure for each break-point, and
then return to the main menu by pressing
E
twice.
9.3.2 Calibration using internal references
This function enables the break-points to be
adjusted without the need for an accurate external
current source. Throughout calibration the
indicator input current may be any value between 4
and 20mA.
The accuracy of this method depends upon the
accuracy of the internal references which should
be calibrated periodically against a traceable
external current source with a resolution of at least
0.4µA. See section 6.7.2
The number of break-points required should first
be entered using the Add and dEL functions. In
both these functions the indicator initially displays
the current break-point and the total number of
break-points being used. e.g.
5 13
current total number of
break-point break-points
Display
Description of function
'Add'
Add a break-point
Adds a new break-point before the
displayed break-point. The calibration
of existing break-points is not changed,
but the identification number of
subsequent break-points is increased
by one.
'dEL'
Remove a break-point
Removes the displayed break-point
and joins the preceding break-point to
the following break-point with a straight
line. The identification of subsequent
break-points is decreased by one.
