Dual Pulse Input Totalizer Modbus or Laurel ASCII Protocol Serial I/O Transmitter

(Rate or total in same transmitter, square root extraction. DIN Rail mounted, digitally programmable.)
Features Standard Main Board
  • Selectable Modbus or Laurel ASCII protocol.
  • Two independently field-scalable pulse input channels.
  • Square root extraction for differential pressure flow transducers
  • Up counting from zero to preset value using positive scale factor.
  • Isolated 5V, 10V or 15V dc excitation output to power transducers.
  • DIN rail mount package only 22.5 mm thick.
  • Easy setup using Laurel's PC-based Instrument Setup Software.
  • Pulse input rates 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.
  • Output scalable to six transmitted digits:
    • Span adjust from 0 to ±999,999.
    • Zero adjust from -999,999 to +999,999.
  • Down counting from preset to zero using negative scale factor.
  • 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.
Features Extended Main Board
All capabilities of the Standard Counter, plus:
  • Channel A total and Channel B rate simultaneously.
  • Counting on Channel A, using Channel B to inhibit counting.
  • Up/down counting on Channel A, using Channel B to control count direction.
  • Arithmetic functions A+B, A-B, AxB, A/B, A/B-1 (draw).
Laureate TM Series serial output, pulse input totalizer 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 pulse rates can be as high as 1 MHz.

With a Standard Main Board, the transmitter output can be scaled to engineering units, for example to transmit totalized flow in gallons from a flow meter output. 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), or A/B-1 (draw or relative elongation of material between rollers).

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.

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.

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 Custom 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).
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

AC Line Frequency
total4 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.
RPM and Speed
total3 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.
Flow Rate and Simultaneous Total
total7 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.
Combining Two Rates
total1 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.
Custom Curve Linearization
total5 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
5672 Bolsa Avenue Huntington Beach, CA 92649 - USA - Ph (714) 622-2000 - Fax (714) 622-2001