Micron Quadrature Encoder
Position & Rate Meter

Standard Features

• Accepts low-level differential or single-ended 5V logic level outputs from quadrature encoders.
• Quadrature count x1, x2 or x4
• Combined encoder pulse rate to 250 kHz
• Programmable display update rate up to 25/s
• Zero channel input
• 6-digit user-scalable display
• Isolated 5, 10 or 24 Vdc excitation output to power encoder
• Green or red LED display.
• Universal AC power, 85-264 Vac
• External controls for reset, meter hold and decimal points
• NEMA 4X, 1/8 DIN case
• Certified to UL 61010C-1 (UL mark), EN 61010-1 (CE mark), and RoHS
  
  Options:
• Low voltage power: 10-48 Vdc or 12-30 Vac
• Dual or Quad relays: Form C contact or Form A solid state
• Analog output: Isolated, 4-20 mA, 0-20 mA, 0-10V, -10 to +10V
• Serial communications: RS232, RS485, Modbus RS485, USB, USB-to-RS485 converter

Description

Position, Length or Angle Measurement

The Micron quadrature meter with the Standard counter main board accepts the A & B quadrature signals from linear encoders and 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 counted. The meter totalizes the counts and then scales the total in software for display and control. A zero index signal, or Z 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 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.
  
• In the event of a power failure, the laatest total may be stored in non-volatile memory and can be used as the starting point for counting when power resumes. Power fail save or zero index capabilities are alternate meter setup choices.

Interface Capabilities

A built-in isolated 5, 10, or 24 Vdc excitation supply can power the encoder and eliminate the need for an external power supply. Plug-in isolated analog output, dual or quad setpoint controller, and serial communications boards can upgrade the Micron quadrature meter from a stand-alone display to system interface and control. In particular, the meter can provide an isolated 4-20 mA or 0-10V output signal scaled to the display.

Controlling the repetitive cutting of material to length is an excellent application of the Micron 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.

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 Micron 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.

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 Micron 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 Micron 6-digit remote display could be added to read out peak rate.