Dual Pulse Input Channels for Frequency, Rate & Period 4-20 mA Current Transmitter

Rate or total in same transmitter, square root extraction. DIN Rail mounted, digitally programmable.
Standard Main Board
  • Isolated 4-20 mA or 0-10V transmitter outputs, selectable.
  • Output resolution: 0.025% of span (12 bits).
  • Inputs from NPN or PNP proximity switches, contact closures, digital logic, magnetic pickups down to 12 mV, or AC inputs up to 250 Vac.
  • Output accuracy: ±0.05% of span.
  • Square root extraction standard.
  • DIN rail mount package only 22.5 mm thick.
  • Easy setup using Laurel's PC-based Instrument Setup Software.
  • Two independently field-scalable pulse input channels.
  • Frequencies from 0.005 Hz to 1 MHz.
  • 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.
  • High update rate.
  • 5V, 10 V or 15V dc excitation output to power sensors.
  • Detachable screw clamp plug connectors.
  • Optional dual solid state relays for alarm or control.
Extended Main Board
All capabilities of the Standard Counter, plus:
  • Rate and total simultaneously.
  • Arithmetic functions A+B, A-B, AxB, A/B, A/B-1 (draw).
  • Custom curve linearization.
Laureate TM Series serial output, pulse input frequency, rate and period transmitters accept 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 measurement, RPM or speed from proximity switch inputs, and flow rates or totals 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 can be via Modbus commands or 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).
Exceptional Accuracy and Stability
Laureate pulse input frequency and rate transmitters determine frequency by taking the inverse of period as measured with a calibrated (±2 ppm) quartz crystal time base. This results in extremely accurate and stable 6-digit internal readings (±999,999 counts), which are then scaled in software to engineering units such as Hz, RPM, liters/sec, or gallons/minute. The inverse period approach provides greater accuracy and faster update times than conventional counters, which count pulses over a specified time interval. The full conversion accuracy is maintained in the Modbus output.

To reduce the effects of signal noise, a count by 10 or 100 feature with rounding is selectable. Variations in the displayed reading can also be reduced by selecting a longer gate time. An adaptive filter can reduce variations due to noise while rapidly responding to actual changes in the signal.

The update rate of the analog output is a programmed gate time + 30 ms + 0-2 signal periods. AC line frequency may be accurately measured to 50.0000 or 60.0000 Hz in a few line cycles. 1000 Hz signals may be measured to 0.01 Hz resolution at up to 25 readings per second. Fast response is ideal for alarm and control applications.

Transmitter programming is via the unit's three-terminal serial port using Laurel's PC-based Instrument Setup Software. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL03). Laurel's serial output transmitters and meters can also be part of PC-based data logging systems using Laurel's Datalogging Software, which operates under the Laurel ASCII Protocol. A single software command switches between the Modbus and Laurel ASCII Protocols.

Laureate transmitters are housed in a 35 mm DIN rail case that is only 22.5 mm (0.89") thick. Signal connections are via detachable screw clamp plug connectors.


Analog Input
Types AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups.
Grounding Common ground for channels A & B.
Channel A Frequency 0.005 Hz to 1 MHz.
Channel 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

Output Levels 4-20 mA and  0-10 Vdc (selectable)
Compliance, 4-20 mA 10V ( 0-500 ohm load )
Compliance, 0-10V 2 mA ( 5 kOhm load )
Output Resolution 12 bits (4,096 steps)
Output Accuracy ±0.05% 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
Transducer Excitation Output (standard)
Jumper Selection 1 10V @ 60 mA, isolated to 50V from signal ground
Jumper Selection 2 5V @ 50 mA, isolated to 50V from signal ground
Jumper Selection 3 15V @ 60 mA, non-isolated
Dual Relay Output (optional)
Relay Type Two solid state relays, SPST, normally open, Form A
Load rating 120 mA at 130 Vac or 170 Vdc, 28 ohms series resistance.
Power Input
Standard power 95-240V AC ±10% or 90-300V DC
Low power option 12-30V AC or 10-48V DC
Frequency DC or 47-63 Hz
Power Isolation 250V rms working, 2.3 kV rms per 1 min test.
Case Dimensions 120 x 101 x 22.5 mm
Case Mounting 35 mm rail per DIN EN 50022
Electrical Connections Detachable screw clamp plug connectors
Operating Temperature 0°C to 70°C
Storage Temperature -40°C to 85°C
Relative Humidity 95% at 40°C, non-condensing

Typical Applications

AC Line Frequency
The Laureate will accept line voltages up to 250 Vac and display 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
The Laureate can sense the low-level signals from magnetic pickups or the NPN or PNP transistor output of active sensors. These can be powered directly by the meter. Display in RPM or units of speed is achieved by mathematically scaling the meter.
Flow Rate and Simultaneous Total
The Laureate is 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. The Extended version can also linearize flow transducers so as to extend their dynamic range.
Combining Two Rates
The Extended Laureate offers 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
The Extended Laureate 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
The Laureate dual channel rate meter 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. The displayed rates can also be transmitted as isolated isolated 4-20 mA or 0-10V analog output.
Pinout Laureate Serial Output Transmitters
Pulse Input for Frequency, Rate or Period
(shown with optional analog output and dual relay output)
Pinout, Serial ASCII or Modbus Transmitter, Frequency, Rate or Period Input
Transmitter Powering a Single Sensor
Pinout, Serial ASCII or Modbus Transmitter, Frequency, Rate or Period Input Pinout, Serial ASCII or Modbus Transmitter, Frequency, Rate or Period Input
Transmitter Powering Two Sensors Transmitter with Active or Passive Sensors
5672 Bolsa Avenue Huntington Beach, CA 92649 - USA - Ph (714) 622-2000 - Fax (714) 622-2001