7
6. CALIBRATION
The BA304C 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 BA304C 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. However,
when verification is not required, the instrument
may be fitted with an internal calibrator which
allows rapid calibration without the need for
exter-nal instruments or disconnection from the
4/20mA input current. See section 8.2 for details.
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
Fig 6 Position of plug-in links and potentiometers
