Pulse Total to 4-20 mA Converter & Serial Data Output Transmitter

The Laureate pulse input to 4-20 mA converter and serial data output transmitter accepts totals from two independently scalable input channels from a wide range of pulse sources, such as NPN or PNP proximity switches, contact closures, digital logic, magnetic pickups down to 12 mV, or AC voltages to 250 Vac. Input pulse rates can be as high as 1 MHz.

With a Standard Main Board, the transmitter output can be scaled to track total (such as gallons) or rate (such as gallons per minute). Square root extrac­tion is standard.

With an Extended Main Board, the transmitter can also:

• Count up to a preset or down from a preset to zero. Such applications typically utilize the transmitter's two solid state relays, which are standard. External reset of totals is via a special three-position screw terminal connector.
• Perform custom-curve linearization on rate or total, for example to extend the range of transducers. Exceptionally accurate custom-curve linearization is provided by a curvilinear spline fit with up to 180 data points.
• Combine channels A and B arithmetically so that the transmitter output tracks A+B (e.g., sum of two flows or totals), A-B (e.g., difference of two flows or totals), AxB (e.g., horse­power as product of force and RPM), A/B (ratio of two flow or totals), and A/B-1 (draw or relative elongation of material between rollers).

The dual-channel signal conditioner used for pulse detection accepts inputs from proximity switches with PNP or NPN output, TTL or CMOS logic, magnetic pickups, contact closures, and voltage signals from 12 mV to 250 Vac. Jumper selections provide optimum operation for different sensor types and noise conditions. A built-in 5V, 10V or 24V dc excitation supply can power proximity switches and other sensors, and eliminate the need for an external power supply.

Standard features of Laureate LTE transmitters include:

• Dual input signals from proximity switches with PNP or NPN output, TTL or CMOS logic, magnetic pickups, contact closures or voltage signals from 12 mV to 250 Vac.
• 4-20 mA, 0-20 mA, 0-10V or -10V to +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 loops.
• Serial communications output, RS232 or RS485 (half or full duplex), jumper selectable. 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 is simpler than the Modbus protocol and is recommended when all devices are Laureates.
• Dual solid state relays, isolated, for alarm or control. Rated 120 mA at 140 Vac or 180 Vdc.
• Transducer excitation output, isolated. User selectable 5V@100 mA, 10V@120 mA or 24V@50 mA.
• Universal 85-264 Vac power. Low-voltage 10-48 Vdc or 12-32 Vac power is optional.

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).

Laureate Ethernet & 4-20 mA Output Transmitter with Dual Pulse Totalizer Inputs