Ethernet & 4-20 mA Transmitter for Load Cell & Microvolt Signals

The Laureate load cell or microvolt input transmitter is designed for use with load cells, strain gauges and microvolt input signals where exceptional sensitivity and stability are required. A most sensitive full-scale input range ±20 mV can be scaled internally to ±99,999 counts. The selected input range for the full 0-20 mA output span can be as wide as ±99,999 counts or as narrow as 150 counts, limited only by considerations of electrical noise and time constants of the programmable moving average digital filter. The unit's serial data output is accurate to ±0.01% of reading ±2 counts in ratiometric load cell mode and ±0.01% of full scale in ±2 counts in absolute microvolt meter mode.

A built-in, isolated, 10V, 120 mA excitation supply can power up to four 350-ohm load cells in parallel. Load cell connection can be via 4 or 6 wires. With 4-wire load connection, the transmitter operates in a ratiometric mode to eliminate errors due to power supply variations. With 6-wire load connection, it also compensates for lead resistance, allowing long cable runs.

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.

• An unfiltered selection provides true peak and valley readings and aids in control applications.
• A batch average filter selection averages each 16 conversions for an update every 1/4 sec.
• An adaptive moving average filter selection provides a choice of 8 time constants from 80 ms to 9.6 s. When a significant change in signal level occurs, the filter adapts by briefly switching to the shortest time to follow the change, then reverts back to its selected time constant. An Auto setting selects the time constant selection based on signal noise.

Standard features of Laureate LTE transmitters include:

• Ethernet I/O, isolated. The supported protocols are Modbus RTU and ASCII, which are tunneled via Modbus TCP. Note that RS232 or RS485 data I/O is provided by Laurel's LT Series transmitters.
• 4-20 mA, 0-20 mA or 0-10V analog transmitter output, isolated, jumper-selectable and user scalable. All selections provide 16-bit (0.0015%) resolution of output span and 0.02% output accuracy of a reading from -99,999 to +99,999 counts that is also transmitted digitally. Output isolation from signal and power grounds eliminates potential ground loop problems. The supply can drive 20 mA into a 500 ohm (or lower) load for 10V compliance, or 10V into a 5K ohm (or higher) load for 2 mA compliance.
• Dual solid state relays, isolated. Available for local alarm or control. Rated 120 mA at 130 Vac or 180 Vdc.
• Universal 85-264 Vac power. Low-voltage 10-48 Vdc or 12-32 Vac power is optional.

Node discovery and configuration of Laureate Ethernet transmitters are easily achieved with Laurel's Windows based Instrument Setup Software. Additional features are provided by Laurel's Windows based Node Manager Software, such as the ability to send emails or test messages either periodically or in the event of an alarm. Both softwares run on a PC under MS Windows, are at no charge, and can be downloaded from this website.