BEKA BA405C, Руководство пользователя

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6. CALIBRATION
The BA405C output currrent does not require any
calibration, the front panel multi-turn control will
always adjust the output current between
approximately 3.5 and 21mA.
6.1 Internal display
The internal display requires calibrating so that the
4/20mA loop current is shown in the required
engineering units.
The BA405C will be supplied with the display
calibrated as requested at time of ordering. If
calibration is not requested, the display will be set
to show 00.0 with 4.000mA loop current and 100.0
with 20.000mA loop current.
The display is calibrated by plug-in links and two
multi-turn potentiometers which are accessible
through holes in the rear panel. To
gain access to the links the rear panel must be
removed as shown in Fig 8.
For maximum accuracy the display should be
calibrated using a traceable current measuring
device with an accuracy greater than 4µA.
Fig 8 Removal of rear panel
6.1.1 Zero adjustment
Zero is defined as the number displayed when the
BA405C output is 4.000mA, and may adjusted
between -1000 and 1000. The zero
potentiometer has two ranges 0 to 500 and 500 to
1000. Tthe polarity of the zero is defined by the
position of the suppression / elevation links.
Fig 9 shows the position of the zero links and zero
potentiometer.
Suppression / elevation links
Elevation Positive zero 0 to 1000
or Suppression Negative zero 0 to -1000
Zero link
0 to 500
or 500 to 1000
6..1.2 Span adjustment
Span is defined as the difference between the
number displayed at 4.000mA and the number
displayed at 20.000mA output. The span
potentiometer has four ranges defined by the span
links, and may be adjusted to any number between
0 and 1999.
Fig 9 shows the position of the span links and span
potentiometer.
Span links
000 to 500
or 500 to 1000
or 1000 to 1500
or 1500 to 1999
6.1.3 Decimal point
A dummy decimal point may be displayed between
any of the four digits. The position or absence of
this decimal point is determined by
the position of the decimal point link shown in Fig
9. When calculating the required span and zero
setting the decimal point should be ignored.
6.1.4 Reverse action
Normally the BA405C display increases as the
loop current increases, but this can be reversed.
Please contact BEKA associates for details.