4-20 mA Current Output Transmitter
for Frequency, Rate or Period Input
Dual channels. Rate and total in same transmitter.
DIN Rail mounted, digitally programmable.

Standard Features

Isolated 4-20 mA or 0-10V transmitter outputs, selectable

Two independently field-scalable pulse input channels

Frequencies 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.

Internal conversion of input to six-digit reading:
- Digital span adjust from 0 to ±999,999
- Digital zero adjust from -999,999 to +999,999

Output resolution: 0.0015% of span (16 bits)

Output accuracy: ±0.02% of span

High update rate

Square root extraction standard

DIN rail mount package only 22.5 mm thick

Plug-in screw-clamp connectors

Easy setup with PC-based Instrument Setup Software

5V, 10V or 24V dc sensor excitation output, isolated

Dual solid state relays for alarm or control, isolated

RS232 or RS485 serial communications, isolated

Universal AC power, 85-264 Vac

Priced at only $235 (basic pulse input transmitter)
Options:

Extended Main Board for rate and total simultaneously, custom curve linearization, arithmetic functions A+B, A-B, AxB, A/B, A/B-1 (draw).

Low voltage power, 10-48 Vdc or 12-32 Vac.

Description

The Laureate 4-20 mA 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. The transmitter output can be selected as 4-20 mA, 0-20 mA or 0-10V, and is isolated to avoid ground loops. 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 transmitters include:

Analog transmitter output, 16-bit, user scalable and isolated. User selectable 4-20 mA, 0-20 mA or 0-10V levels.
Serial communications, isolated. User selectable RS232 or RS485, half or full duplex, Modbus or Laurel ASCII protocol.
Dual solid state relays for control or alarm, isolated. 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 AC power supply for 85-264 Vac.

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

Analog Input

Types

Grounding
Channel A Frequency
Channel B Frequency
Minimum Signal
Maximum Signal
Noise Filter
Contact Debounce
Time Base Accuracy

AC, pulses from NPN, PNP transistors, contact closures,
magnetic pickups.
Common ground for channels A & B
0.005 Hz to 1 MHz
0.005 Hz to 250 kHz
Nine ranges from (-12 to +12 mV) to (+1.25 to +2.1V)
250 Vac
1 MHz, 30 kHz, 250 Hz (selectable)
0, 3, 50 ms (selectable)
Quartz crystal calibrated to ±2 ppm

Analog Output (standard)

Output Levels
Compliance, 4-20 mA
Compliance, 0-10V
Output Resolution
Output Accuracy
Output Update Rate
Output Isolation

4-20 mA and 0-10 Vdc (selectable)
10V ( 0-500 ohm load )
2 mA ( 5 kOhm load )
16 bits (65,536 steps)
0.02% of output span
Programmed gate time + 30 ms + 0-2 signal periods
250V rms working, 2.3 kV rms per 1 minute test

Sensor Excitation Output (standard)

Output Levels
Output Isolation

5V@100 mA, 10V@120 mA, 24V@50 mA (jumper selectable)
50V from signal ground

Dual Relay Output (standard)

Relay Type
Load Rating

Two solid state relays, SPST, normally open, Form A
130 mA at 140 Vac or 180 Vdc

Serial Communications (standard)

Signal Types
Data Rates
Output Isolation
Serial Protocols
Modbus Modes
Modbus Compliance
Digital Addressing

RS232 or RS485 (half or full duplex)
300, 600, 1200, 2400, 4800, 9600, 19200 baud
250V rms working, 2.3 kV rms per 1 min test
Modbus RTU, Modbus ASCII, Laurel ASCII
RTU or ASCII
Modbus over Serial Line Specification V1.0 (2002)
247 Modbus addresses.
Up to 32 devices on an RS485 line w/o a repeater.

Power Input

Standard Power
Low Power Option
Power Frequency
Power Isolation
Power Consumption

85-264 Vac or 90-300 Vdc (DC operation not UL approved)
10-48 Vdc or 12-32 Vac
DC or 47-63 Hz
250V rms working, 2.3 kV rms per 1 min test
2W typical, 3W with max excitation output

Mechanical

Dimensions
Mounting
Electrical Connections

128 x 103 x 22.5 mm
35 mm rail per DIN EN 50022
Plug-in screw-clamp connectors

Environmental

Operating Temperature
Storage Temperature
Relative Humidity
Cooling Required

0°C to 55°C
-40°C to 85°C
95% at 40°C, non-condensing
Mount transmitters with ventilation holes at top and bottom.
Leave 6 mm (1/4") between transmitters, or force air with a fan.

Application Examples of Frequency / Rate Meters
AC Line Frequency
	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
	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.
Flow Rate and Simultaneous Total
	Laureate frequency meters andtransmitters 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
	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
	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 RS-232 or RS-485, including peak readings and arithmetic combinations of the two rates.

Pinout
Laureate 4-20 mA Transmitter for Frequency, Rate or Period Input

Ordering Guide
Laureate 4-20 mA Transmitter for Frequency, Rate or Period
Click on the radio buttons to build a model number with pricing (shown below the Ordering Guide).

Quantity
Transmitter Type	LTA Laureate 4-20 mA Transmitter	$235
Main Board	6 Standard Main Board 8 Extended Main Board	NC $40
Main Board	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 1 Isolated 12-32 Vac or 10-48 Vdc	NC $30
Relay Output	0 None 2 Isolated Dual Solid State Relays	NC NC
Input Type	FR Dual-Channel Frequency	NC
Accessories	CBL04 RS-232 cable, TA to computer or USB adapter CBL02 USB to RS-232 cable adapter	$19 $39