Laureate TM Series serial output, pulse input transmitters accept two independently scalable input channels A & B 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 frequencies can range from 0.005 Hz to 1 MHz. With the Standard main board, the transmitter output can be programmed to track rate or total for both channels. With the Extended main board, as used in the transmitters being presented in this web page, the transmitter output can also be programmed to track the sum, difference, product, ratio, or draw of both channels: A+B, A-B, AxB, A/B, A/B-1. These arithmetic operations can be applied to scaled rates, scaled totals, square root of rates, totals after square root extraction, custom curve linearized rates, or totals after custom curve linearization.

• Sum can be used to add two flows for total flow, or to add parts carried by two conveyor belts.
    
• Difference can be used to subtract outflow from inflow for net flow, or to subtract reject parts from total parts.
    
• Product can be used to multiply two rates, for example to compute  horsepower by multiplying torque by RPM.
    
• Ratio can be used to compare flow rates in two channels, the RPM of rollers or gears, or the speed of moving machinery, such as conveyor belts. Ratio can also be applied to scaled totals to compare two batches to be mixed. In this application, one transmitter is used to monitor the ratio of flow rates, and a second transmitter to monitor the resulting batch totals.
    
• Draw is obtained by subtracting 1 from ratio. Draw is used to measure the elongation of material as it passes between rollers, or to monitor variation in the speed of rollers for tensioning.

Exceptional Accuracy and Stability

Laureate pulse input frequency and rate transmitters determine frequency by taking the inverse of period as measured with a calibrated quartz crystal time base. This results in extremely accurate and stable 6-digit internal readings (±999,999 counts), which are then processed in software. The output update rate is a programmed gate time + 30 ms + 0-2 signal periods. For a 60 Hz signal, the update rate would be 20 per second. Such fast update rates are ideal for alarm and control applications.

The output of the transmitters presented in this web page can be selected as 4-20 mA or 0-10V and is isolated to avoid ground loops. This output is generated by an ultra-linear 12-bit (4096 step) digital-to-analog convert (DAC), whose output span can be adjusted from 0 to ±999,999 input counts and zero can be adjusted from -999,999 to +999,999 input counts. The analog output has a rated accuracy of ±0.05% of output span.

The update rate of the analog output is a programmed gate time + 30 ms + 0-2 signal periods. For a 60 Hz signal, the update rate would be 20 per second. Such fast update rates are ideal for alarm and control applications.

Transmitter programming is via a three-terminal RS-232 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).

The transmitters are housed in a DIN rail case that is only 22.5 mm (0.89") thick. Signal connections are via detachable screw clamp plug connectors.