14
Fig 9 Location of security code override link
5.14 Over and under-range
If the range of the digital display is exceeded, the
four least significant digits will be blanked. Under-
range is indicated by '-1' and over-range by '1'.
Under and over-range are also indicated if the
input current falls below approximately 3.5mA or
rises above approximately 21mA.
The bargraph displays an upward pointing arrow
when overrange occurs and a single negative
segment and the zero bar for underrange.
If the instrument input current falls below 3mA the
initialisation sequence is performed as described
in section 2.
6.
CALIBRATION EXAMPLES
The following examples illustrate the two ways in
which a BA526C indicator may be calibrated.
6.1
Using an external current source
The BA526C indicator is required to display:
0.0
with a 4mA input
1500.0
with a 20mA input
from a linear level transducer. Maximum display
resolution is required, the frequency of the local
mains is 50Hz and the existing security code is
1209.
In the operating mode the indicator is
required to display the input current as a
percentage of span when the
P
push-button is
operated.
Step 1
Connect indicator to calibrator
Connect the indicator to an accurate
external current source.
Terminal 1
positive.
The
indicator
will
automatically perform the initialisation
routine described in section 2, and then
display the input current using the
existing calibration information.
Step 2
Enter programming mode
With an input current between 4 and
20mA
put
the
indicator
in
the
programming mode by simultaneously
pressing
P
and
E.
The indicator will
respond by displaying 'COdE'. Press
P
to clear this prompt and set the display
to the security code 1209 using the
Up
,
Down
and
P
push-buttons. Pressing
E
will enter the code, and after a few
seconds during which the decimal
points
will
be
scrolled,
the
first
parameter 'root' in the main menu will
be displayed.
Step 3
Square root extraction
With 'root' displayed, press
P
which
will reveal the root extractor status.
The root extractor can be turned on or
off by the
Up
or
Down
buttons. Select
'OFF', and press
E
to return to the main
menu.
Содержание BA526C
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