Red Lion LEGEND - Manual (Page 8)

The following is a Block Diagram overview of the basic operation.
OVERFLOW INDICATION
The Legend will flash the word “OVERFLOW” in the appropriate display
when an overflow condition occurs. An overflow occurs if the capacity of the
display (6-digits) is exceeded or if the internal count capacity (9-digits) is
exceeded. The use of an extremely small Scale Multiplier and a Scale Factor
Value can cause the internal count capacity to overflow before the displayed
value will overflow.
For example, if a Scale Factor of 0.0001 and a Scale Multiplier of 0.001 is
used, for every 10,000,000 count edges received, the display will increment
by 1. Before the display reaches 215, the internal counter will overflow.
When the capacity of the display is exceeded, the count value will be
maintained and will be valid. But if the internal count capacity is exceeded,
then this value will no longer be valid. It should be noted that the use of a
Scale Factor larger than “1” could cause the displayed count value to
overflow before 999,999 counts are accumulated. Also the use of a Rate Scale
Factor, Scale Multiplier, and Rate Conversion Factor larger than “1” can
cause the rate display to be in an overflow condition.
The Counter should not be allowed to operate in an overflow condition. As
soon as, or before the counter overflows, the information should be recorded
and the counter reset.
INHIBIT
When the Inhibit terminal is low, connected to common, all input pulses will
be ignored by the counter. The rate input, however, is unaffected by the Inhibit
terminal and will continue to indicate the rate of the signal at input A. When the
Inhibit terminal is high, the signal for the counter will be sensed and counted.
PEAK & VALLEY
The Peak and Valley registers will record the lowest (Valley) and the
highest (Peak) readings of the rate input signal. These values are viewed in
the indication display loop and are updated automatically. A User Input can
be programmed to reset the values to the current rate value individually or by
sending the proper command via the serial communication port. The Peak and
Valley values are NOT retained when power to the unit is removed.
NORMAL OPERATING MODE
In the normal operating mode, the up, down, left, and right arrow keys are
used to scroll through the main display loop. In the main display loop, the four
indication displays, scale factor, and program mode module are viewed, as
shown. In the indication display loop, the up and down arrow keys are used to
scroll to each display. The indication displays are referenced as 1 (RATE), 2
(PEAK), 3 (VALLEY), and 4 (COUNT), and are the factory default settings.
The indication displays can be programmed to show other parameters and
automatically scroll if desired (Refer to the Program Displays Module).
When exiting the indication display loop, using the left or right arrow keys,
the last display that was viewed will be the first display to be viewed when
re-entering the indication display loop. Also, the last indication display that
was viewed at power down, will be the one viewed on power up.
The Presets and Counter Load values are accessed from any of the indication
displays or from the programming loop. The Count and Rate scale factors are
accessed from the Scale Factors display or when in the programming loop from
the Program Scaling module. In the Program Mode display, the operator enters
the programming loop to access all parameters to configure the unit.
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