Lineshaft Pacer Encoders

Interfacing a position encoder to an ORMEC ServoWire Drive can provide vital position information to the motion control system.

This approach is simple, yet effective, because information from the "encoder axis" is available to be used in the same way that information is used from any "servo axis".

Key Features

• Heavy Duty sealed bearings and NEMA 4X housing
• Flange Mount with integral coupling and servo mount configurations available
• 200 KHz Frequency response for all channels
• Optional 2X, 4X, 5X or 10X cycle interpolation
• Maximum Data Rate increases to match cycle interpolation
• LED light source

Remote Encoders Uses

• Pacer Encoders measure real-time shaft position data of a machine axis to be sent to other servo axes in the system when electronic gearing and/or cam profiling are used in an application.
• Programmable limit switches on each ServoWire drive can be configured to turn on or off based on pacer encoder position.
• Position and velocity information is accessible from the application program for every encoder used with an XD-Indexer, SMLC or ORION^® system.
• Remote Feedback Encoders can be used to provide position feedback directly from the load under control. This is usually used in conjunction with velocity feedback from the servo motor shaft to provide an additional level of precision for the control system.

ServoWire Drive Interface

The encoder interface is a partial servo axis interface, consisting only of differentially received quadrature A and B channels and a reference Z-channel. Selecting the "encoder input" axis control mode disables servo drive alarm detection but still provides open wire detection to insure encoder position information integrity.

Optical Position Encoders

ORMEC's Model EDR-25 optical, incremental position encoders are ideal for a wide variety of rugged industrial motion applications where reliability is a prime concern.

LED light sources rated for 100K hours MTBF, 40 pound axial/35 pound radial shaft loading capability, 200 KHz frequency response allow these encoders to be effective in harsh, industrial applications.

The EDR-25 provides a 1/4 cycle wide gated zero reference output. Models with cycle interpolation have maximum resolutions up to 200,000 counts per shaft revolution.

Electrical Specifications

• Resolution range: Discs can be provided with up to 5000 lines. This results in resolutions up to 20,000 counts per revolution with standard quadrature decoding, or to 200,000 counts per revolution with internal 10X cycle interpolation.
• Light sources: Gallium Aluminum Arsenide LEDs rated for 100,000 hours MTFB (manufacturer’s specification)
• Light sensors: Photovoltaic
• Excitation voltages: 5 VDC @ 245 mA maximum. Units with cycle interpolation require a maximum of 450 mA.
• Output format: Two outputs (A and B) in phase quadrature with a zero reference (Z) output
• Quadrature specification: 90° +12°; with internal cycle interpolation: 90° +45° (at 10KHz output frequency)

Symmetry specification:

• 180° +5° (at 10 KHz output frequency)
• Rise & Fall times: 1 usec (maximum) into 1000 pf of load capacitance
• Frequency response: Units without cycle interpolation: 200 KHz for all channels. Units with cycle interpolation obtain 400, 800 & 1000 KHz.
• Zero Reference angular width: 1 +1/4 count channel cycle. Units provide a 1/4 cycle wide gated zero (Z) reference.
• Phase sense: Channel A leads Channel B for CCW rotation of the shaft as viewed from shaft end (face end) of the unit.
• Output Specifications: Output stage is an MC3487 (or performance equivalent) differential line driver with 40 ma sink and -40 ma source current.

Mechanical Specifications

• Maximum Shaft loading: 40 lbs. axially, 35 lbs. radially
• Shaft radial runout: 0.001" T.I.R.
• Maximum Starting torque at 25C:
• EDR-25C (without shaft seal): 2.0 oz-in
• EDR-25S (with shaft seal): 5.0 oz-in
• Shaft angular acceleration: 105 radians/sec² (maximum)
• Moment of inertia: 4.7 x 10-4 oz-in-sec²
• Bearing type: Sealed class ABEC 7
• Minimum Bearing Life: 2 x 10⁹ revolutions at rated shaft loading. (Bearing life increases to 5 x 1010 revolutions at 10% of rated shaft loading.)
• Shaft: 303 stainless
• Maximum shaft speed: 6000 RPM or 200 KHz count channel output frequency, whichever occurs first (before cycle interpolation).
• Weight: 17 oz. (maximum)
• Error: +0.5 bits maximum (based on ORION® 4X counting circuitry); +1.0 bits maximum (applies to units with cycle interpolation)

Coupling Specifications (EDR-25C)

• Maximum Wind-up: 30 arc-seconds per oz-in
• Maximum Angular Misalignment: 5°
• Maximum Axial Play: +0.010 in
• Maximum Parallel Misalignment: 0.010 in
• Environmental Specifications
• Operating temperature range: 0 to +70C
• Storage temperature range: -25 to +90C
• Maximum Shock: 50G’s for 11 milliseconds duration
• Vibration: 20 Hz to 2000 Hz at 20G’s
• Maximum Humidity: 98% R.H. (non-condensing)