Features

• Accepts low-level differential or single-ended 5 V logic level outputs from shaft encoders.
• Quadrature count x1, x2 or x4.
• Combined pulse rate to 250 kHz.
• Programmable display refresh rate up to 25/s.
• Zero channel input.
• 6-digit display scalable for direct readout in units of length.
• Isolated 5, 10 or 24 Vdc excitation output to power shaft encoder.
• AC or DC powered.
• Green or red LED display
• NEMA 4X, 1/8 DIN case
• Dual relay option
• Analog output option
• Serial communication options
• Low voltage AC & DC power
• Certified to UL 61010C-1 (UL mark), EN 61010-1 (CE mark), and RoHS.

Position, Length or Angle Measurement

The Laureate™ quadrature meter with the Standard counter main board accepts the A & B signals from shaft encoders to provide a highly accurate, scaled display of position, length, or angle in engineering units, such as ft, cm or degrees.

The A & B quadrature signals are 90º out of phase, and their phase relationship determines whether up counts (+) or down counts (-) are produced. The meter totalizes the counts and then scales the total in software for display and control. A zero index signal may be added as a third input to the A & B signals.

Scaled Rate Measurement

Use of the Extended counter main board can convert the quadrature meter from scaled position to scaled rate. For example, it can display the speed of a moving slab in ft/sec. Simultaneous display of position and rate will require two meters. The display and control output update rate for position or rate is normally set to a maximum of 25/s, as determined by a user-programmable gate time.

Quadrature Meter Capabilities

• One, two or four transitions may be counted at a maximum combined rate of 250 kHz and be mathematically scaled for display in engineering units from -999,999 to +999,999. The quadrature board has 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.
   
• A zero index pulse, if available, is interpreted as by the meter as corresponding to an integral number of revolutions of the shaft encoder. It is used by the meter to correct for any cumulative pulse count errors. Special circuitry corrects for width of the zero index pulse.
   
• 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.<

Differential or single-ended quadrature
x1, x2 or x4
250 kHz at x1, 125 kHz at x2, 62.5 kHz at x4
No error contributed by meter
+200 mV
-200 mV
± 7V
2.5V to 10V
-1V to +1V
17 kOhm

Inverse period
Gate time + 30 ms + 0-2 signal periods
Selectable 10 ms to 199.99 s
Selectable 10 ms to 199.99 s
Same as conversion time
Calibrated to ±2 ppm

Using Quadrature for Cutting to Length

Controlling the repetitive cutting of material to length is an excellent application of the Laureate quadrature meter.

The quadrature encoder shares the shaft of a sensing wheel, whose rotation corresponds to lineal displacement of material. The meter compares the displacement reading against setpoint information, and then uses its dual relays to first slow down and then cut the material.

Using Quadrature for X-Y Positioning

Accurate X-Y position or rate can be obtained from two shaft encoders, which convert linear position to quadrature signals as a shaft turns. In addition to serving as a display, each Laureate can use its optional dual relay setpoint capability for closed loop control. It can also transmit data via RS-232, RS-485, or a 4-20 mA analog signal.

Using Quadrature to Monitor a Drilling Operation

Quadrature can be used to track position and vertical drilling speed of the bit in an oil drilling operation. A shaft encoder is rotated by a cable that moves with the drilling shaft.

In this application, the same encoder signal is applied to a Laureate quadrature meter for position, and to a second quadrature meter for rate. Both meters can be scaled to read out in appropriate engineering units, such as feet and inches per minute, and can be alarmed. A Laureate 6-digit remote display could be added to read out peak rate.