Standard Features

The Laureate Modbus & serial output totalizing transmitter accepts 0-1 mA, 4-20 mA or 0-10V signals from flow meters and other transducers, such as watt meters, to track rate or totalized rate.

• 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 also perform custom curve linearization (provided by a curvilinear spline fit with up to 180 data points), display 1/ rate (such as the time it takes a conveyor to pass through an oven), and perform batch control for repetitive fill operations.  Such applications typically make use of optional dual solid state relays, which are available as options. External reset of totals is provided by a special connector.

A signal conditioner board converts the full-scale 0-1 mA, 4-20 mA or 0-10 V analog signal to a frequency of 10 kHz to 110 kHz. This frequency is determined by measuring period over a selected gate time (from 10 ms to 200 s) and taking the inverse of period. At the lowest frequency of 10 kHz and the minimum gate time of 10 ms, the transmitter is capable of 25 updates per second. Scaling is done mathematically. Totals are stored in nonvolatile memory in case of power loss.

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 of Laurel 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).