7
6. CALIBRATION
The BA304NC will be supplied calibrated as
requested at time of ordering. If calibration is not
requested, the indicator will be set to display 00.0
with 4.000mA input, and 100.0 with 20.000mA
input.
The BA304NC is conditioned and calibrated by
plug-in links and two multi-turn potentiometers.
For maximum accuracy, the instrument should be
calibrated using an external traceable current
source with a resolution of at least 4µA.
Fig 6 Location of calibration links
and potentiometers
6.1 Zero adjustment
Zero is defined as the number displayed by the
indicator with a 4.000mA input current and may be
adjusted between -1000 and 1000. The zero
potentiometer has two ranges, 0 to 500 and 500 to
1000. Zero polarity is defined by the position of
the suppression / elevation links which are shown
in Fig 6.
Suppression / elevation links
Position
Display with 4mA input
adjustable between
Elevation 0 and 1000
Suppression 0 and -1000
Zero link
Position
Display with 4mA input
adjustable between
0 to 500
0 and 500
500 to 1000
500 to 1000
6.2 Span adjustment
Span is defined as the difference between the
number displayed with 4.000mA input and the
number displayed with 20.000mA input. It is
adjustable between 0 and 1999 in four ranges. Fig
6 shows the position of the span links and the span
potentiometer.
Difference in display
Position with 4 & 20mA input
of span links adjustable between
000 to 500
000
and 500
or 500 to 1000
500
and 1000
or 1000 to 1500
1000
and 1500
or 1500 to 1999
1500
and 1999
6.3 Decimal point
A dummy decimal point may be displayed between
any of the four digits. The position or absence of
this dummy decimal point is determined by the
position of the decimal point link shown in Fig 6.
When calculating the required span and zero
settings the decimal point should be ignored.
6.4 Reverse action
Normally the BA304NC display increases as the
input current increases, but this can be reversed.
Please contact BEKA associates for details.
