Laurel Electronics LAUREATE SERIES COUNTER_TIMER - Manual (Page 4)

1. INTRODUCTION
The series of panel instruments is a versatile, cost effective solution to a wide variety of
monitoring and control applications. These instruments are easily set to produce an
accurate display of frequency, rate, total, period, time interval, phase, position , flow, etc.
Front panel pushbutton or RS-232/RS-485 setup allows the user to customize the unit for
a specific application. Digital scaling of zero and span provides direct readout in
engineering units. A high stability crystal and digital calibration of all ranges eliminates
drift associated with potentiometers found in non-microcomputer-based meters. The
meter measures the period of the input signal to calculate frequency or rate. This fast
read rate provides an accurate display of peak signal input and quick response in control
applications. Selectable gate time (10ms to 99s) and adaptive filter ensure stable
displayed readings and outputs while responding rapidly to changes of the input signal.
Selective security lockout of the front panel setup protects against accidental changes to
the meter configuration and simplifies use by the operator. The series uses a lightweight,
high-efficiency switching power supply that operates from either AC or DC voltages and
complies with safety regulations. The meter can be powered worldwide without changes
to the supply. An optional low voltage supply operates on 9 to 37 Vdc from batteries or
8 to 28 Vac from sources such as 400 Hz aircraft power. Both supplies have isolated 5,
10, and 24Vdc excitation outputs to power transducers. The NEMA 4 (IP65) 1/8 DIN case
is made of high impact, 94V-0 UL-rated plastic. Mounting is from the front of the panel and
requires less than 110 mm behind the panel. All wiring is by removable plugs conforming
to IEC950 safety standards. All output options are isolated from meter and power ground
by 250 Vac minimum.
The dual setpoints have two form C ( 10 A @ 250 Vac ) relays or open collector outputs
for alarm and control capabilities. Either setpoint may be latching or nonlatching and may
be separately configured to be energized above or below the setpoint or in a fail-safe
mode. Outputs may also be selected to operate from the filtered signal to reduce relay
chatter or from the unfiltered signal for fast response. Snubber circuits and program-
mable relay switching time delay extend relay contact life.
Isolation of the 4 to 20 mA and 0 to +10 V analog outputs eliminates ground loop problems.
The output may be scaled by front panel pushbuttons or RS-232/RS-485. For square root
and custom curves, the output is linearized. Depending on the application, the analog
output may be selected to operate from the filtered or unfiltered signal input. The 4 to 20
mA output will drive up to an 800 Ohm load with 16 V compliance
The meter offers RS-232 or RS-485 bidirectional communications or parallel, 3-state
BCD output to interface with computers, PLC’s or other digital devices. IBM PC
compatible software is available for programming of the unit by the RS-232 and RS-485
interfaces.
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