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3. PRODUCT INTRODUCTION
Our digital panel meters
are versatile, cost effective solutions to a wide variety of monitoring
and control applications. Depending on the choice of signal conditioner, they are easily set up
for an accurate display of temperature, pressure, flow, weight, voltage or current, all in appro-
priate engineering units and with zero and span adjustment when needed. Setup can be via front
panel pushbuttons or the meter’s serial interface. Selective security lockout of the front panel
keys protects against accidental changes to meter setup.
High read rates
up to 60 per second (50 for 50 Hz operation) are made possible by Concurrent
Slope Conversion, which integrates the signal over an AC power line cycle for maximum noise
rejection. High read rates provide accurate peak and valley capture, and quick response for
control applications. An adaptive digital filter supplies a time constant for the encountered signal
noise level yet responds rapidly to changes that exceed a selected threshold. Self-calibration
occurs automatically after every 17th reading.
The standard built-in power supply
is a high-voltage switching supply that operates from
worldwide AC power or from 90-300 Vdc. A low-voltage supply is optional for power from 24
Vdc, 10-48V batteries, or 12-30 Vac. Both supplies provide an isolated 5, 10 or 24Vdc transducer
excitation output.
The meter case
conforms to the 1/8 DIN size standard and fits in a 45 x 92 mm panel cutout. It
is made of high impact, 94V-0 UL-rated plastic and is watertight to NEMA-4 (IP65) when panel
mounted. Mounting is from the front of the panel and requires less than 110 mm behind the
panel. Power and signal wiring is via removable plugs conforming to UL61010C safety stan-
dards. All output options are isolated from meter and power ground to 250 Vac.
Extended meter versions
. Up to 180 data points may be linear-
ized by a computer program that stores setup parameters in nonvolatile memory. Extended
meters can also display time rate of change.
Alarm or setpoint control
can be provide by an optional board with 2 or 4 relays. These can
be 8A mechanical or 120 mA solid state relays. The setpoints may be latching or non-latching,
be energized above or below the setpoint, or operate in a fail-safe mode. The relays can operate
from the filtered signal to reduce relay chatter or from the unfiltered signal for fastest response.
An isolated analog output
of 4-20 mA, 0-20 mA, 0-10V or -10 to +10V can be provided by an
optional analog output board. The output is linearized to the display and can operate from the
filtered or unfiltered signal input. It can be scaled via front panel pushbuttons or the meter’s serial
interface.
USB, RS232 or RS485 communications
are available with the Modbus RTU protocol or
Laurel’s simpler Custom ASCII protocol. RS485 operation allows up to 32 meters to be daisy-
chained over long distances with no need for a hub. A USB-to-RS485 gateway board allows up
to 32 meters to be interfaced to a PC via a single USB cable.
Ethernet communications
are supported by two versions of an Ethernet board, both of which
support the Modbus TCP protocol. An Ethernet-to-RS485 gateway board allows up to 32 meters
to be interfaced to a network via a single Ethernet cable.
Meter programming
can be
via the meter’s front panel or a PC running Windows based
. A communication board is required in the meter but can be removed
following meter setup.
