Red Lion LEGEND - Manual (Page 7)

Input A accepts a signal for the Count and Rate display. Input B accepts a
signal for the Count display or direction control. In the Anti-coincidence
mode, both inputs are monitored simultaneously, so that no counts are lost,
and the final count can be chosen as the sum or difference of the two inputs.
Rate and Count displays have separate scaling and decimal point
placement, for the readouts in different units.
The Counter Load feature enables the operator to modify the count value
under circumstances that occur when flawed material has been counted and it
is necessary to adjust the count value accordingly.
The rate operates in the time interval method (1/tau) to calculate the rate
value. This method insures high resolution at all input rates. Averaging can be
accomplished by programming the Minimum and Maximum Update Time for
the desired response. Extensive scaling capabilities allow practically any
reading at very slow input rates.
Each of the two open collector outputs can be assigned to either the
Counter or Rate indicator. The programmable outputs can be set for a variety
of functions. The optional plug-in relay board operates in parallel with the
open collector outputs and makes it easy to field upgrade the Legend unit to
provide for two, 5 amp, 240 VAC relay outputs.
The construction of the Legend LGD unit is a lightweight, high impact
plastic case with a clear viewing window. The sealed front panel with the
silicone rubber keypad meets NEMA 4X/IP65 specifications for wash-down
and/or dusty environments, when properly installed. Plug-in style terminal
blocks simplify installation and wiring change-outs.
SAFETY SUMMARY
All safety related regulations, local codes and instructions that appear in
the manual or on equipment must be observed to ensure personal safety and to
prevent damage to either the instrument or equipment connected to it. If
equipment is used in a manner not specified by the manufacturer, the
protection provided by the equipment may be impaired.
Do not use this unit to directly command motors, valves, or other actuators
not equipped with safeguards. To do so, can be potentially harmful to persons
or equipment in the event of a fault to the unit.
BASIC OPERATION
The Legend has a counter that keeps track of the input pulse Count. The unit
takes the actual number of pulses counted (internal count value) and multiplies
them by the Count Scale Factor and Count Scale Multiplier. This results in the
desired reading value for the count display. The unit can count on both edges of
the pulse if desired. Input A accepts the signal for the count and Input B is used
for quadrature or anti-coincidence counting, or to control up or down counting.
There is a separate Inhibit terminal that can be used with any of the count modes.
The Counter has three Reset Action modes associated with the display;
Reset to Zero (up-count modes), Reset to Preset (down-count modes), or
Reset to the Counter Load value. A Reset can be a Manual reset, using a
programmable user input, or it can be one of the seven programmable
Automatic Reset modes. Both the reset action and automatic reset modes are
programmed in the Program Counter Module.
The Counter will display the scaled number of pulses that have been
entered. When the count equals either preset 1 or 2, the appropriate output
will activate. The count can be programmed to automatically reset if desired.
The internal precision of the Counter is maintained to 9 digits.
The signal at Input A is also used for the Rate indicator portion. The Rate
Indicator uses a time interval method (1/tau) to calculate the rate value. The
unit counts on the negative edge of the input pulses. After the programmed
minimum update time elapses and the next negative edge occurs, the unit
saves the number of edges that occurred during the elapsed time. The number
of edges is multiplied by the Rate Scale Factor, Rate Scale Multiplier, and the
Rate Conversion Factor to calculate the rate value. Averaging can be
accomplished by programming the Rate Minimum Update Time for the
desired response. Extensive scaling capabilities allow practically any desired
reading at very slow count rates.
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