Laurel Electronics LT: 4-20 mA & Serial Data Output Transmitter for Dual Channel Pulse Totalizer Input - Manual

LAUREL ELECTRONICS INC. , 3183-G Airway Ave., Costa Mesa, CA 92626, USA • Tel 714-434-6131 • www.laurels.com 1
LAUREL
ELECTRONICS, INC.
4-20 mA & Serial Data Output Transmitter
for Dual Channel Pulse Totalizer Input
Features
• Two independently field-scalable pulse input channels
• Up counting from zero to preset value using positive scale factor
• Down counting from preset to zero using negative scale factor
• Inputs from NPN or PNP proximity switches, contact closures, digital logic, or
magnetic pickups down to 12 mV, pulse rates to 1 MHz
• 5V, 10V or 24V dc transducer excitation output, isolated
• 4-20 mA or 0-10V transmitter output, jumper selectable, isolated
• Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span
• RS232 or RS485 serial data output, half or full duplex, isolated
• Modbus RTU, Modbus ASCII or Laurel ASCII protocol
• Dual solid state relays for alarm or control, isolated
• Universal AC power, 85-264 Vac, or low voltage power, 10-48 Vdc or 12-32 Vac
Description
The Laureate pulse input totalizer transmitter accepts two
independently scalable input channels from a wide range of pulse
sources, such as NPN or PNP proximity switches, contact
closures, digital logic, magnetic pickups down to 12 mV, or AC
voltages to 250 Vac. Input pulse rates can be as high as 1 MHz.
With a Standard Main Board, the transmitter output can be
scaled to track total (such as gallons) or rate (such as gallons per
minute). Square root extraction is standard.
With an Extended Main Board, the transmitter can also:
• Count up to a preset or down from a preset to zero. Such
applications typically utilize the transmitter’s two solid state
relays, which are standard. External reset of totals is via a
special three-position screw terminal connector.
• Perform custom-curve linearization on rate or total, for
example to extend the range of transducers. Exceptionally
accurate custom-curve linearization is provided by a curvi-
linear spline fit with up to 180 data points.
• Combine channels A and B arithmetically so that the
transmitter output tracks A+B (e.g., sum of two flows or totals),
A-B (e.g., difference of two flows or totals), AxB (e.g., horse-
power as product of force and RPM), A/B (ratio of two flow or
totals), and A/B-1 (draw or relative elongation of material
between rollers).
The dual-channel signal conditioner used for pulse detection
accepts inputs from proximity switches with PNP or NPN output,
TTL or CMOS logic, magnetic pickups, contact closures, and
other signals from 12 mV to 250 Vac. Jumper selections provide
optimum operation for different sensor types and noise condi-
tions. A built-in 5V, 10V or 24V dc excitation supply can power
proximity switches and other sensors, and eliminate the need for
an external power supply.
Standard features of Laureate transmitters include:
• 4-20 mA, 0-20 mA or 0-10V analog transmitter output,
isolated, jumper-selectable and user scalable. All selections
provide 16-bit (0.0015%) resolution of output span and 0.02%
output accuracy of a reading from -99,999 to +99,999 counts
that is also transmitted digitally. Output isolation from signal
and power grounds eliminates potential ground loop problems.
The supply can drive 20 mA into a 500 ohm (or lower) load for
10V compliance, or 10V into a 5K ohm (or higher) load for 2
mA compliance.
• Serial communications output, isolated. User selectable
RS232 or RS485, half or full duplex. Three protocols are user
selectable: Modbus RTU, Modbus ASCII, or Laurel ASCII.
Modbus operation is fully compliant with Modbus Over Serial
Line Specification V1.0 (2002). The Laurel ASCII protocol
allows up to 31 Laureate devices to be addressed on the
same RS485 data line. It is simpler than the Modbus protocol
and is recommended when all devices are Laureates.
• Dual solid state relays, isolated. Available for local alarm or
control. Rated 120 mA at 130 Vac or 170 Vdc.
• Transducer excitation output, isolated. User selectable
5V@100 mA, 10V@120 mA or 24V@50 mA.
• Universal 85-264 Vac power. Low-voltage 10-48 Vdc or
12-32 Vac power is optional.
Easy Transmitter programming is via Laurel's Instrument
Setup Software, which runs on a PC under MS Windows. This
software can be downloaded from our website at no charge. The
required transmitter-to-PC interface cable is available from Laurel
(P/N CBL04).