Modbus & Serial Output Transmitter for Process Signal Input

Scalable for process signals requiring zero and span adjustment. Ideal for pressure & flow. DIN Rail mounted, digitally programmable.
  • Easy setup with PC-based Instrument Setup Software
  • DIN rail mount housing only 22.5 mm wide
  • Detachable screw-clamp connectors
  • 5V, 10V or 24V dc transducer excitation output, isolated
  • Dual solid state relays for alarm or control, isolated
  • 0-10V, 4-20 mA or 0-20 mA analog output, scalable, isolated
  • 200 mV, 2V, 20V, 200V, 300V & 600V DC voltage ranges
  • 2, 20, 200 mA and 5A DC current ranges
  • All ranges factory calibrated
  • Digital span adjust from 0 to ±99,999
  • RS232 or RS485 serial communications, half or full duplex, isolated
  • Modbus RTU, Modbus ASCII or Laurel ASCII protocol
  • Output update rate to 60/sec
  • 4-20 mA, 0-20 mA or 0-10V transmitter output, jumper selectable, isolated
  • Universal AC power, 85-264 Vac
  • Priced at only $235 (basic process transmitter)
  • Digital zero adjust from -99,999 to +99,999
The Laureate Modbus & serial output, process signal input transmitter provides six DC voltage input ranges and four DC current input ranges for use with a wide range of transducers whose output requires zero and span adjustment. All ranges are factory calibrated and jumper selectable. The two most sensitive voltage ranges, 200 mV and 2V, provide a high input impedance of 1 Gohm to minimize the load on the voltage signal.

Fast read rate at up to 50 or 60 conversions per second while integrating the signal over a full power line cycle is provided by Concurrent Slope (Pat 5,262,780) analog-to-digital conversion. High read rate is ideal for peak or valley capture and for real-time computer interface and control. Digital signal filtering modes are selectable for stable readings in electrically noisy environments. The internal digital readings and analog output can be individually selected to be either unfiltered or filtered.

LTM Series serial output transmitters send data via an isolated serial port, which is user configurable for RS232 or RS485 and full or half duplex operation. 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 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 ofLaurel Datalogging Software.
Standard features of Laureate transmitters include:
Serial data output, isolated. User selectable RS232 or RS485, half or full duplex, Modbus or Laurel ASCII protocol.

Dual solid state relays for control or alarm, isolated. Rated 120 mA at 130 Vac or 170 Vdc.

Transducer excitation output, isolated. User selectable 5V@100 mA, 10V@120 mA or 24V@50 mA.

Analog transmitter output, 16-bit, user scalable and isolated. User selectable 4-20 mA, 0-20 mA or 0-10V levels.

Universal AC power supply for 85-264 Vac.

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).


Analog Input Range Input Ohms
Voltage 200.00 mV 
2.0000 V
20.000 V
200.00 V
600.0 V
1 Gohm
1 Gohm
1 Mohm
1 Mohm
1 Mohm
Current 2.0000 mA
20.000 mA 
200.00 mA 
5.000 A
100 ohms
10 ohms
1 ohm
0.01 ohm
Input Resolution 16 bits (65,536 steps)
Input Accuracy ±0.01% of full scale ± 2 counts
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 5A
Transducer Excitation Output (standard)
Output Levels 5V@100 mA, 10V@120 mA, 24V@50 mA (jumper selectable)
Output Isolation 50V from signal ground
Serial Data Output (standard)
Signal Types RS232 or RS485 (half or full duplex)
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 Modes RTU or ASCII
Modbus Compliance Modbus over Serial Line Specification V1.0 (2002)
Digital Addressing 247 Modbus addresses.
Up to 32 devices on an RS485 line w/o a repeater.
Dual Relay Output (standard)
Relay Type Two solid state relays, SPST, normally open, Form A
Load Rating 130 mA at 140 Vac or 180 Vdc
Analog Output
Output Levels 0-20 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 16 bits (65,536 steps)
Output Accuracy 0.02% of output span plus conversion accuracy
Output Isolation 250V rms working, 2.3 kV rms per 1 minute test
Power Input
Standard Power 85-264 Vac or 90-300 Vdc (DC operation not UL approved)
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
Dimensions 129 x 104 x 22.5 mm case
Mounting 35 mm rail per DIN EN 50022
Electrical Connections Plug-in screw-clamp connectors
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 Laureate Modbus & Serial Output Transmitter for Process Signal Input
Custom curve linearization
A Laureate process meter or 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