Process, Strain Gauge & Potentiometer Follower Input Modbus

(DIN Rail mounted, digitally programmable. Exceptional accuracy at high update rates.)
  • Selectable Modbus or Laurel ASCII protocol.
  • Digital span adjust from 0 to ±99,999.
  • 0.2, 2, 20, 200, 300V & 600V DC voltage ranges.
  • All ranges factory calibrated.
  • Output accuracy: ±0.01% of full scale input.
  • Built-in 5V, 10V or 15V transducer excitation output.
  • Detachable screw terminal connectors.
  • Optional dual solid state relays for alarm or control.
  • Modbus RTU or ASCII modes, 2-wire connection, up to 247 digital addresses.
  • Digital zero adjust from -99,999 to +99,999.
  • 2, 20, 200 mA and 5A DC current ranges.
  • Peak value capture and auto-tare.
  • Output update rate to 60/sec.
  • DIN rail mount package only 22.5 mm thick.
  • Easy setup using Laurel's PC-based Instrument Setup Software.
  • Optional isolated scalable analog output (4-20 mA or 0-10V).
DC Ranges.  Laureate TM Series, DC input transmitters provide six voltage ranges and four current ranges, all factory calibrated and jumper selectable. The 200.00 mV and 2.0000 V ranges provide a high input impedance of 1 Gohm to minimize the load on the voltage signal. A 5.000A range measures the IR drop across a built-in 10 mW current shunt. The transmitters can also easily be scaled in software for use with external shunts.

Serial Data 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 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.

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 Range Resolution Input Ohms
Voltage 200.00 mV 
2.0000 V 
20.000 V
200.00 V
600.0 V
10 µV
100 µV
1 mV
10 mV
100 mV
1 Gohm
1 Gohm
1 Mohm
1 Mohm
1 Mohm
Current 2.0000 mA
20.000 mA,
200.00 mA
5.000 A
0.1 µA
1 µA
10 µA
1 mA
100 ohms
10 ohms
1 ohm
0.01 ohm
Input Resolution 16 bits (65,536 steps)
Input Accuracy ±0.01% of full scale input (determined by ADC).
Output Update Rate, Max 50/sec at 50 Hz, 60/sec at 60 Hz.
Max applied voltage 600 Vac for 20, 200 & 600 V ranges, 125 Vac other ranges.
Over-current protection 25x for 2 mA, 8x for 20 mA, 2.5x for 200 mA, 1x for 5 A.
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 Process, Strain Gauge & Potentiometer Follower Input
(shown with optional analog output and dual relay output)
Use as an Isolated, Linearized 4-20 mA Transmitter
Strain Gauge Transmitter
Externally Powered 4-Wire Process Transmitter 2-Wire Process Transmitter
Application Examples
Potentiometer Application
In potentiometric (or potentiometer follower) applications, the signal from a sliding contact voltage divider can be converted to engineering units such as position, level or percentage. By operating in a ratiometric mode, the transmitter will remove any effects caused by variations in the excitation supply. For use with a 1 kohm potentiometer, the recommended applied excitation voltage is 10V, and a 2 kohm resistor should be placed in series with the excitation output and excitation return leads. This will allow the transmitter's 2V scale with a high input impedance of 1 Gohm to be used.
Custom curve linearization
tx-ta-dc3A Laureate process transmitter with the Extended main board option allows exceptionally accurate custom curve linearization. For setup, up to 180 data points can be entered into a spreadsheet. The system then creates multiple non-linear spline-fit segments, which provide much better accuracy than linear segments. One application, as illustrated, is the readout of volume of irregularly shaped tanks based on measured liquid level or pressure. Altimeters and thermistors are further applications.
5672 Bolsa Avenue Huntington Beach, CA 92649 - USA - Ph (714) 622-2000 - Fax (714) 622-2001