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Transmitters, 4-20 mA & Modbus - Panel Meters - Counters - Timers - Ethernet - USB - RS485 - RS232

4-20 mA & Serial Data Transmitter for Frequency, Rate or Period Input

Dual channels. Rate and total in same transmitter. DIN Rail mounted, digitally programmable.

Transmitter for frequency, rate or period

Standard Features

  • 4-20 mA, 0-20 mA, 0-10V or -10V to +10V transmitter output, 16 bits, isolated
  • RS232 or RS485 serial data output, Modbus or Laurel ASCII protocol, isolated
  • Dual 120 mA solid state relays for alarm or control, isolated
  • Two independently field-scalable pulse input channels from 0.005 Hz to 1 MHz
  • Inputs from NPN or PNP proximity switches, contact closures, digital logic,
    magnetic pickups down to 12 mV, or AC inputs up to 250 Vac
  • Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span
  • DIN rail mount housing only 22.5 mm wide, detachable screw-clamp connectors
  • 5V, 10V or 24V dc transducer excitation output, isolated
  • Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power
  • Extended main board for simultaneous rate and total, custom curve linearization, arithmetic functions A+B, A-B, AxB, A/B, A/B-1 (optional)
Description

The Laureate 4-20 mA and RS232/RS485 transmitter for frequency, rate or period 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 frequencies can range from 0.005 Hz to 1 MHz. Applications include AC line frequency, RPM or speed from proximity switch inputs, and flow from turbine flow meter inputs.

  • With a Standard Main Board, the transmitter output can be scaled to track frequency in Hz, rate (such as gallons per minute), or period (inverse of frequency). Square root extraction is standard.
  • With an Extended Main Board, the transmitter output can track rate or totalized rate (such as gallons) whether the transducer output is linear, requires square root extraction, or requires custom curve linearization. The latter can be provided by a curvilinear spline fit with up to 180 data points. The transmitter can also count up to a preset total or down from a preset total to zero. Such applications typically make use of optional dual solid state relays, which are available as options. External reset of totals is via a special three-position screw terminal connector. The two input channels A & B can also be combined arithmetically to provide an analog transmitter output that tracks A+B (e.g., sum of two flows), A-B (e.g., difference of two flows), AxB (e.g., horsepower as product of force and RPM), A/B (ratio of two flow), and A/B-1 (draw or relative elongation of material between rollers).
Signal conditioner board used with 4-20 mA current transmitter for frequency, rate or period

Exceptional Accuracy and Stability. Laureate pulse input frequency and rate transmitters determine frequency by taking the inverse of period as measured with a calibrated quartz crystal time base. This results in extremely accurate and stable 6-digit internal readings (±999,999 counts), which are then processed in software. The analog output is generated by an ultra-linear 16-bit (65,536 step) digital-to-analog converter (DAC) for 0.02% output accuracy.

The update rate of the transmitter output is a programmed gate time + 30 ms + 0-2 signal periods. For a 60 Hz signal, the update rate would be 20 per second. Such fast update rates are ideal for alarm and control.

Standard features of Laureate LT transmitters include:

  • 4-20 mA, 0-10V or -10V to +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.
  • Serial communications output, RS232 or RS485 (half or full duplex), jumper selectable. 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 is simpler than the Modbus protocol and is recommended when all devices are Laureates.
  • Dual solid state relays, isolated, for 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 this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL04).

Specifications
Laureate 4-20 mA Transmitter for Frequency, Rate or Period Input
Signal Input
Types AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups
Grounding Common ground for channels A & B
Chan. A Frequency 0.005 Hz to 1 MHz
Chan. B Frequency 0.005 Hz to 250 kHz
Minimum Signal Nine ranges from (-12 to +12 mV) to (+1.25 to +2.1V)
Maximum Signal 250 Vac
Noise Filter 1 MHz, 30 kHz, 250 Hz (selectable)
Contact Debounce 0, 3, 50 ms (selectable)
Time Base Accuracy Quartz crystal calibrated to ±2 ppm
Analog Output (standard)
Output Levels 4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable)
Compliance, 4-20 mA 10V (0-500Ω load)
Compliance, 0-10V 2 mA (5 kΩ load)
Output Resolution 16 bits (65,536 steps)
Output Accuracy 0.02% of output span
Output Update Rate Programmed gate time + 30 ms + 0-2 signal periods
Output Isolation 250V rms working, 2.3 kV rms per 1 minute test
Serial Data Output (standard)
Signal Types RS232 or RS485 (half or full duplex), jumper selectable
Data Rates 300, 600, 1200, 2400, 4800, 9600, 19200 baud
Output Isolation 250V rms working, 2.3 kV rms per 1 min test
Serial Protocols Modbus RTU, Modbus ASCII, Laurel ASCII
Modbus Compliance Modbus over Serial Line Specification V1.0 (2002)
Ethernet Connector RJ45 jack for 10/100Base-T Ethernet cable
RS232/485 Connector Screw terminals for easy daisy chaining
Digital Addresses 247 for Modbus, 31 for Laurel ASCII
Dual Relay Output (standard)
Relay Type Two solid state relays, SPST, normally open, Form A
Load Rating 120 mA at 140 Vac or 180 Vdc
Sensor Excitation Output (standard)
Output Levels 5V@100 mA, 10V@120 mA, 24V@50 mA (jumper selectable)
Output Isolation 50V from signal ground
Power Input
Standard Power 85-264 Vac or 90-300 Vdc
Low Power Option 10-48 Vdc or 12-32 Vac
Power Frequency DC or 47-63 Hz
Power Isolation 250V rms working, 2.3 kV rms per 1 min test
Power Consumption 2W typical, 3W with max excitation output
Mechanical
Dimensions 129 x 104 x 22.5 mm case
Mounting 35 mm rail per DIN EN 50022
Electrical Connections Plug-in screw-clamp connectors
Environmental
Operating Temperature 0°C to 55°C
Storage Temperature -40°C to 85°C
Relative Humidity 95% at 40°C, non-condensing
Cooling Required Mount transmitters with ventilation holes at top and bottom. Leave 6 mm (1/4") between transmitters, or force air with a fan.
Pinout
Laureate LT transmitter pinout
Applications Examples
AC Line Frequency
AC Line Frequency Meter or Transmitter Laureate frequency meters and transmitters accept line voltages up to 250 Vac and output line frequency to 6-digit accuracy (50.0000 or 60.0000) in a few line cycles. Fast low frequency response is achieved by timing the period and taking its inverse.
RPM and Speed
Tachometer and Pulse Input Rate Meter or Transmitter Laureate frequency meters and transmitters can sense low-level signals from magnetic pickups or the NPN or PNP transistor output of active sensors. These can be powered directly by the meter or transmitter. Output in RPM or units of speed is achieved by mathematical scaling.
Simultaneneous Flow Rate and Total
Simultaneous Rate Meter and Totalizer Mode of Frequency Meter or Transmitter Laureate frequency meters and transmitters are compatible with all flow meters which generate pulses at a frequency proportional to flow rate. The Extended version can display scaled rate or total for the same input at the push of a button, and alarm from both the rate and total.
Combining Two Rates
Dual Pulse Input Rate Meter or Transmitter to Combine Two Rates Extended Laureate frequency meters and transmitters offer A+B, A-B and A/B arithmetic functions. A+B allows two input flows to be summed for total flow, while A-B allows outflow to be subtracted from inflow for net flow. Flow ratios aid in the proper mixing of ingredients.
Custom Curve Linearization
Custom Curve Linearization for Laureate Rate Meters and Transmitters Extended Laureate frequency meters and transmitters can linearize the output turbine flow meters, which tend to be nonlinear on the low end. Linearizing improves the dynamic range and accuracy of turbine flow meters.
System-level Capabilities
Laureate dual-channel rate meters and transmitters can independently scale, display and alarm two pulse input channels. All signal or alarm data can further be transmitted via RS232 or RS485, including peak readings and arithmetic combinations of the two rates. System Interfaces of Laureate Frequency Meters, Rate Meters and Transmitters
Ordering Guide
Laureate 4-20 mA & RS232/RS485 Transmitter for Frequency, Rate or Period Input
Click on the radio buttons to build a model number with pricing as shown below. Prices are in US dollars and do not include shipping or duty charges (export sales). Please see our explanations and limitations applicable to pricing and online orders. Prices shown are in US Dollars and are Laurel's manufacturer's suggested retail price (MSRP) in the USA. Orders are processed manually, not directly by our shopping cart system. You don't have to supply credit card information when placing an online order.

North American Orders. Laurel does not sell factory-direct in the USA or Canada. Online sales orders are filled through distribution. During the ordering process, you will have the chance to select an authorized Laurel distributor, or you can ask Laurel to refer you to a distributor. The distributor will then contact you to quote shipping, tax and duty (where applicable), and arrange for payment.

International Orders. If your ship-to address indicates that you are outside of the USA or Canada and Laurel has a distributor in your country, we will forward your order to that distributor for follow-up. If Laurel does not have a distributor in your country, we will email you an order acknowledgment and a pro forma invoice which states the product price, shipping charges, and wire transfer information, which includes a $25 bank wire transfer fee.

Questions about your order? Please email your distributor or sales@laurels.com
Configured model number LT60FR
Configured price per model $235
Quantity 1
Extended price $235
Quantity
Transmitter
Type
LT  4-20 mA & RS232/RS485 output transmitter $235
LTE  4-20 mA & Ethernet output transmitter $295
Main Board 6  Standard Main Board $0
8  Extended Main Board $40
With Standard Main Board: Scalable to ±999,999 for frequency, rate, square root of rate, up or down total, period, A-to-B time interval.
With Extended Main Board: Above, plus rate and total simultaneously, ratio (A/B), draw (A/B-1), other arithmetic functions (AxB, A+B, A-B), phase angle, stopwatch, up/down counting, batching operation, linearization of nonlinear inputs.
 
Power 0  Isolated 85-264 Vac or 90-300 Vdc $0
1  Isolated 12-32 Vac or 10-48 Vdc $30
Input Type FR  Dual-Channel Frequency $0
Accessories CBL04  RS232 cable, 7ft. Connects RS232 screw terminals of LT transmitter to DB9 port of PC. $19
CBL02  USB to RS232 adapter cable. Combination of CBL02 and CBL04 connects transmitter RS232 terminals to PC USB port. $39
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