This Laureate transmitter accepts two independently scalable input channels A & B 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.

Arithmetic functions A+B, A-B, AxB, A/B or A/B-1 are made available by the Extended counter main board and can track the sum, difference, product, ratio, or draw of both input channels. These functions can be applied to scaled rates, scaled totals, square root of rates, totals after square root extraction, custom curve linearized rates, or totals after custom curve linearization.

Sum can be used to add two flows for total flow, or to add the number of parts carried by two conveyor belts.
Difference can be used to subtract outflow from inflow for net flow, or to subtract reject parts from total parts.
Product can be used to multiply two rates, for example to compute horsepower by multiplying torque by RPM.
Ratio can be used to compare flow rates in two channels, the RPM of rollers or gears, or the speed of moving machinery, such as conveyor belts. Ratio can also be applied to scaled totals to compare two batches to be mixed. In this application, one transmitter is used to monitor the ratio of flow rates, and a second transmitter to monitor the resulting batch totals.
Draw is obtained by subtracting 1 from ratio. Draw is used to measure the elongation of material as it passes between rollers, or to monitor variation in the speed of rollers for tensioning.

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. Extremely accurate 6-digit internal readings (±999,999 counts) are processed in software.

The update rate of the transmitter output is a programmed gate time + 30 ms + 0-2 signal periods. For pulse rates of 60 Hz and above, 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, 0-20 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 loops.
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 140 Vac or 180 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).

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 A and B
Arithmetic functions A+B, A-B, AxB, A/B, A/B-1 (draw) applicable to rate or total
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
Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span
5V, 10V or 24V dc transducer excitation output, isolated
Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power

Specifications

Laureate 4-20 mA & RS232/RS485 Data Transmitters for Position or Rate from Quadrature Encoders

Pulse Input
Signal Types	AC, pulses from NPN, PNP transistors, contact closures, magnetic
Signal Ground	pickups
Channel A Frequency	Common ground for channels A & B.
Channel B Frequency	0.005 Hz to 1 MHz
Minimum Signal	0.005 Hz to 250 kHz
Maximum Signal	Nine ranges from (-12 to +12 mV) to (+1.25 to +2.1V)
Noise Filter	250 Vac
Contact Debounce	1 MHz, 30 kHz, 250 Hz (selectable)
Time Base Accuracy	0, 3, 50 ms (selectable)
Arithmetic Functions	Quartz crystal calibrated to ±2 ppm A+B, A-B, AxB, A/B, A/B-1
Analog Output (standard)
Output Levels	4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable)
Compliance at 20 mA	10V (0-500Ω load)
Compliance, 0-10V	2 mA ( 5 kΩ or higher 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 10/100 Base-T Ethernet cable
RS232/RS485 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

Applications

Applications Examples

Controlling the Mixing Ratio of Two Fluids
	Transmitting and alarming the input flow rate ratio of two fluids (gas or liquid) allows these to be mixed in a predetermined ratio in continuous processes. The sensing element is normally a turbine flow meter, which outputs pulses at a frequency proportional to flow rate. The A/B ratio can also be transmitted for totalized rate (or delivered volume).
Comparing Fluid Inflow & Outflow
	The ratio of the inflow and outflow rates of a tank is a measure of the relative filling or emptying rate. The same transmitter can also be programmed to transmit the net inflow or outflow rate in flow units, or to transmit totalized inflow our outflow in volume units. Any of these parameters can be alarmed using the dual relay board and be transmitted via 4-20 mA.
Controlling Coating Thickness on a Film
	In this application, Channel A measures the rate at which a coating material is applied, as measured by a flow meter, while Channel B measures the speed of the film based on pulses from a proximity switch. Transmitting and alarming the A/B ratio assures that an even thickness of coating material is applied as the speed of the film is varies.
Instrumenting a Pulsed Laser System
	The dual-channel Laureate transmitter can measure the speed of conveyor lines by using the output of proximity switches which sense gear teeth or spokes of rotating drive wheels. Transmitting the speed ratio of two lines allows line speeds to be adjusted so that material arrives at work stations when needed.
Measuring Draw for Elongation
	Draw (Ch A / Ch B - 1) can be used to indicate the elongation of films compressed between rollers, the shrinkage films, and the RPM difference of rollers whose speed is varied to maintain tension. The high resolution of Laureate dual channel transmitters is ideal for comparison of rates that are close to each other.