4-20 mA Current Output Transmitter for Position or Rate from Quadrature Encoders

• Accepts low-level differential or single-ended 5V logic level outputs from a shaft encoder, linear encoder, incremental encoder or optical encoder.
• Isolated 4-20 mA, 0-20 mA or 0-10V transmitter outputs, selectable
• DIN rail mount housing only 22.5 mm wide
• Easy setup with PC-based Instrument Setup Software
• Priced at only $265 (basic pulse input transmitter)

• Low voltage power, 10-48 Vdc or 12-32 Vac.

The Laureate 4-20 mA output quadrature transmitter accepts the A & B quadrature encoder signals to provide an analog output that tracks position, length, angle, or rate. The A & B quadrature signals are 90° out of phase, and their phase relationship determines whether up counts (+) or down counts (-) are produced.

One, two or four quadrature transitions may be counted at a maximum combined rate of 250 kHz and be scaled internally to ±999,999. counts. The input circuitry which may be jumpered for either single-ended input signals or for balanced line driver signals. Anti-jitter circuitry eliminates errors produced by vibration of the encoder. In the event of a power failure, the current total may be stored in non-volatile memory and can be used as the starting point for counting when power resumes. Power fail or zero index capabilities are alternate meter setup choices.

A zero index pulse, if available, is interpreted by the meter as indicating a zero reference for an integral number of revolutions of a rotary shaft encoder or the home position of a linear encoder. It is used by the meter for initializing and to correct for any cumulative pulse count errors. Special circuitry corrects for width of the zero index pulse.

Available for Total or Rate

• With the Standard main board, the transmitter totalizes the quadrature counts and then scales the total in software for the output. A zero index Z signal can be added as a third input to the A & B signals. The analog output is generated by an ultra-linear 16-bit (65,536 step) digital-to-analog converter (DAC) for 0.02% output accuracy.
• With the Extended main board, the transmitter can can be programmed to output either total or rate or rate. For example, the output can track the speed of a moving slab from the RPM of a roller. The update rate for rate is a programmed gate time + 30 ms + 0-2 pulse periods.

Standard features of Laureate transmitters include: