Totalizer for 0-1 mA, 4-20 mA or 0-10V Signals Modbus or Laurel ASCII Protocol Serial I/O Transmitter

(Scalable for flow rate, analog square root, totalized flow. DIN Rail mounted, digitally programmable.)
  • Selectable Modbus or Laurel ASCII protocol.
  • Output rate from 0-1 mA, 4-20 mA or 0-10V analog signals.
  • Selectable square root extraction for differential pressure flow transducers.
  • Exceptional accuracy: ±0.005% of input span ±1 count
  • Output update rate: 25/sec.
  • 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.
  • Output scalable to six transmitted digits:
    • Span adjust from 0 to ±999,999.
    • Zero adjust from -999,999 to +999,999.
  • Isolated 5V, 10V or 15V dc excitation output to power transducers.
  • Peak value capture.
  • Detachable screw clamp plug connectors.
  • Optional dual solid state relays for alarm or control.
Laureate TM Series, serial I/0, process signal input totalizing transmitters accept 0-1 mA, 4-20 mA or 0-10V signals from flow meters and other transducers, such as watt meters.

With a Standard Main Board, the transmitter output can track rate (such as gallons per minute or watts) or totalized rate (such as gallons or kilowatt hours) whether the transducer output is linear or requires square root extraction (differential pressure flow transducers).

With an Extended Main Board, the transmitter can provided by a curvilinear spline fit with up to 180 data points. It 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 process transmitters described in this page convert the full-scale 0-1 mA, 4-20 mA or 0-10 V analog input signal to a frequency of 10-110 kHz, which is converted internally to a 6-digit rate reading rate using inverse period timing and a calibrated quartz crystal time base. The analog-to-digital conversion is exceedingly accurate, ±0.005% of span ±1 count at 25°C. It is also fast, at 25 conversions per second. The full conversion accuracy is maintained in the serial output.

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.

Transmitter 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.

DIN Rail Mounting. 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 Modbus Laureate Transmitters

Analog Input 0-1 mA 4-20 mA 0-10 V
Input resistance 182 ohms 9 ohms 1 Mohm
Max current or voltage 37 mA 160 mA 600 V
Input Resolution 6 digits
Span Tempco ±0.0025% R/°C
Zero Tempco ±0.0005 FS/°C
Accuracy at 25°C ±0.005% FS ±1 count
Read Rate 25/sec (typical)
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 terminal connectors.
Operating Temperature 0°C to 70°C.
Storage Temperature. -40°C to 85°C.
Relative Humidity 95% at 40°C, non-condensing.
Pinout Laureate 4-20 mA Transmitters Process Signal Input Rate Transmitter & Totalizer
(shown with optional analog output and dual relay output)
DC & Externally Powered Process Transmitter
Transmitter Powering Two Sensors
5672 Bolsa Avenue Huntington Beach, CA 92649 - USA - Ph (714) 622-2000 - Fax (714) 622-2001