Sum, Difference, Ratio, Product for Rate or Total with 2 Input Channels

(Modbus or Laurel ASCII Protocol Serial I/O Transmitter DIN Rail mounted, digitally programmable.)
Features Standard Main Board
  • Selectable Modbus or Laurel ASCII protocol.
  • Two independently field-scalable pulse input channels.
  • Applicable arithmetic functions: A+B, A-B, AxB, A/B, A/B-1 (draw).
  • Inputs from NPN or PNP proximity switches, contact closures, digital logic, magnetic pickups down to 12 mV, or AC inputs up to 250 Vac
  • Square root extraction standard.
  • DIN rail mount package only 22.5 mm thick.
  • Easy setup using Laurel's PC-based Instrument Setup Software.
  • Modbus RTU or ASCII modes, 2-wire connection, up to 247 digital addresses.
  • Internal conversion of Channel A & B inputs to six-digit readings:
    • Digital span adjust from 0 to ±999,999.
    • Digital zero adjust from -999,999 to +999,999.
  • Frequencies from 0.005 Hz to 1 MHz.
  • High output update rate.
  • Isolated 5V, 10V or 15V dc excitation output to power transducers.
  • Detachable screw clamp plug connectors.
  • Optional dual solid state relays for alarm or control.
Laureate TM Series serial output, pulse input transmitters accept 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. With the Standard main board, the transmitter output can be programmed to track rate or total for both channels. With the Extended main board, as used in the transmitters being presented in this web page, the transmitter output can also be programmed to track the sum, difference, product, ratio, or draw of both channels: A+B, A-B, AxB, A/B, A/B-1. These arithmetic operations 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 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.

freqbd2Laureate 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 output update rate 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 applications.

Laureate TM Series transmitters send data as a serial digital signal. RS485 or RS232 signal levels are jumper selectable and can each be associated with either the Modbus protocol or Laurel’s simpler Laurel ASCII protocol.

Modbus protocol operation is fully compliant with the Modbus Over Serial Line Specification V1.0 (2002) for 2-wire, half-duplex connection. This includes RTU or ASCII modes, addressing of up to 32 devices per RS485 line without a repeater, and up to 247 digital addresses. Modbus operation allows devices by different manufacturers to be connected in parallel and be addressed using the same protocol.

Laurel’s 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. It also allows use of Laurel’s datalogging software.

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.

Options include dual solid state relays for local alarm or control and an isolated 4-20 mA or 10V (selectable) analog output, effectively providing a linearized analog transmitter output that tracks the reading that would be transmitted digitally. The analog output provides 12-bit (4096 step) resolution of the output span and is ultra-linear to within one bit. Its accuracy is ±0.05% of span for all signal types, except for AC rms, where accuracy is ±0.1%. Output isolation from signal and power grounds is provided by a separate on-board power supply, which can drive 20 mA into a 500 ohm load for 10V compliance. Output isolation eliminates problems caused by ground loops.

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.

General Specifications- Laureate Serial Output Transmitter, Load Cell or Microvolt Input

Pulse Input
Types AC, pulses from NPN, PNP transistors, contact closures, magnetic pickups.
Ch A Frequency, Max 1 MHz.
Ch B Frequency, Max 250 kHz.
Signal Ground Common ground for channels A & B.
Minimum Signal Nine ranges from (-12 to +12 mV) to (+1.25 to +2.1V).
Maximum Signal 250 Vac
Maximum Frequency 1 MHz, 30 kHz,  250 Hz (selectable).
Contact Debounce 0, 3, 50 ms (selectable).
Time Base Accuracy Quartz crystal calibrated to ±2 ppm.
Arithmetic Functions A+B, A-B, AxB, A/B, A/B-1
Serial I/O (standard)
Signal levels RS485 (default) or RS232 (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 (selectable)
Devices on RS-485 Line 32 max without a repeater.
Modbus Addresses 247 max
Modbus Modes RTU or ASCII, 2-wire.
Modbus Compliance Modbus over Serial Line Specification V1.0 (2002).
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.
Analog Output (optional)
Output Levels 0-20 mA, 4-20 mA or  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 Isolation 250V rms working, 2.3 kV rms per 1 minute test
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
Controlling the Mixing Ratio of Two Fluids
aoverb2nobox Up/down totalizing is provided by a mode of the Extended totalizing transmitter where pulses are either added or subtracted on Channel A based on a direction input on Channel B. The unit can also be programmed so that counting by Channel A is inhibited by an input on Channel B.
Comparing Fluid Inflow & Outflow
aoverb4nobox A+B, A-B, A/B and AxB arithmetic functions are available with the Extended totalizing transmitter. A+B can sum two totals, while A-B subtracts the outflow total from inflow total. A/B ratio applied to two totals helps assure the proper mixing of components.
Controlling Coating Thickness on a Film
aoverb5nobox A single Laureate dual-channel totalizing transmitter will handle two repetitive fill operations by counting from zero up to a preset, or down from a preset to zero. The dual relay option is required.
Synchronizing Two Conveyor Lines
aoverb1nobox An easy way to measure the ON time of machines is to count AC line cycles and scale the total to hours. To display machine utilization or duty cycle in percent, use the Extended totalizing transmitter. Connect Channel A to switched AC and Channel B to the AC line, and apply a 100 multiplier to the A/B ratio.
Measuring Draw for Elongation
aoverb3nobox The Extended version of the Laureate dual channel totalizing transmitter can transmit scaled rate or total for the same channel at the push of a button, and alarm both the rate and total. The Extended version can also do curve linearization, thereby extending the working range and accuracy of flow transducers.
Pinout Laureate Serial Output Transmitters Pulse Input for Frequency, Rate or Period
(shown with optional analog output and dual relay output)
Transmitter Powering a Single Sensor
tx-ta-dual2a tx-ta-dual3a
Transmitter Powering Two SensorsTransmitter with Active or Passive Sensors
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