Scott QuadScan II 7400, Руководство по эксплуатации и техническому обслуживанию, Страница: 25 / 121

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System Operation
General
The QuadScan II allows up to 4 inputs of 0/4 - 20 mA and converts these inputs to digital displays on a LCD. An input
current of 4 mA corresponds to a display of 0.00, and an input current of 20 mA corresponds to the programmed full-
scale digital display. Displays are checked against programmed alarm levels (set points) to illuminate LEDs, activate
relays, and sound the internal horn. The input current loops are also used to generate isolated 4 - 20 mA output
current loops.
Display Readings
The LCD is capable of displaying digital ranges from 000 to 1999. A decimal point may appear in the digital display,
which is set automatically by the programmed channel full-scale display. Possible full-scale displays with respective
digital ranges are shown below.
Full Scale Decimal Precision
1.00 – 9.99 2 digits
10.0 – 99.9 1 digit
100 – 1999 0 digits
The decimal point is fixed and does not change once set.
The LCD may be programmed for one of the three gas concentration units or none at all.
% Percent
PPM Parts Per Million
PPB Parts Per Billion
none --
Contrast may be set for the LCD during setup and programming, which may provide a clearer view of the digital
display from various angles.
The LCD can be programmed with up to a maximum of six (6) alphanumeric characters to display specific customer
information such as transmitter location, area identification etc.
Visual Indications (LEDs)
The visual indications located on the digital/function assembly are divided into two distinct sections; channel status
and alarm status. These sections are located just below the LCD.