The Celera MicroE ChipEncoder Series is a compact, high-performance encoder system designed for integration into electronic products, particularly for high-volume applications and automated assembly processes. It functions as an encoder system on a chip, providing precise position feedback for both linear and rotary motion.
Function Description:
The ChipEncoder system utilizes an infrared laser diode to read patterns on glass scales, generating digital quadrature output signals (A, B, and Index Window) in CMOS/TTL format. These signals provide position information, with interpolation depths of X4 or X40 depending on the model, allowing for fine resolution. The system is designed for direct mounting onto a printed circuit board (PCB), making it suitable for compact designs. It supports both linear and rotary glass scales, offering flexibility for various motion control applications. The encoder's output signals can be monitored via a digital oscilloscope for alignment and troubleshooting.
Important Technical Specifications:
- Models: CE300-4, CE300-40 (7 mm x 11 mm package), and CE-40GC (6 mm x 6 mm package).
- Scale Pitch: 40 µm for all compatible scales.
- System Resolution:
- CE300-4: 10 µm linear resolution (X4 interpolation).
- CE300-40, CE-40GC: 1 µm linear resolution (X40 interpolation).
- Rotary resolution varies by scale type; refer to the "Linear and Glass Scales" section for details.
- Accuracy:
- Linear Glass: ±5 µm/m.
- Rotary Glass: ±2 arc-seconds (excludes eccentricity).
- Power Supply: 5 VDC ±0.5 VDC. Minimum 4.5 VDC continuously, maximum 5.5 VDC.
- Current Draw: 30 mA (unterminated outputs).
- Operating Temperature: 0°C to 70°C.
- Storage Temperature: -20°C to 85°C (CE300), -20°C to 100°C (CE).
- Max Lead-Free Reflow Temperature: 260°C for <5 seconds.
- Humidity: 10% to 90% RH, non-condensing (operating).
- Vibration: 30 G @ 20 Hz; EN60068-2-6.
- Shock: 300 G (0.40, half sine) for CE300; 100 G (11 ms, half sine) for CE.
- Reliability (MTTF): 100,000 Hours.
- Output Signals: CMOS/TTL, digital differential quadrature format.
- Output Impedance: 60 ohms per channel.
- Sensor Dimensions (Width x Length x Height):
- CE300: 7.0 x 11.0 x 3.1 mm.
- CE: 6.1 x 6.1 x 3.9 mm.
- Sensor Weight:
- CE300: 0.37 g.
- CE: 0.25 g.
- Laser Safety: Invisible laser radiation, wavelength 850 nm, maximum power 2.4 mW CW. CDRH Class 1 range. Caution: Do not view directly with optical instruments when powered.
Usage Features:
- Installation: The ChipEncoder is designed for surface mount technology (SMT) and reflow soldering processes. Detailed instructions for PCB land pattern design and assembly are provided, recommending adherence to IPC-7351 standards. A 0.003 - 0.005 inch thick stainless steel stencil is recommended for solder paste application.
- Alignment: Optimal performance is achieved by adhering to MicroE System's interface drawings for mechanical mounting. Fine-tuning and verification can be done using the Sin+ and IW+ signals. Sin+ (sinusoidal function with ~1.7 V offset) should have a peak-to-peak range of 1.1 - 2.1 V. IW+ (active-high TTL pulse) should be 40 µm wide ±25%.
- Scale Mounting: Linear glass scales can be attached using two primary methods:
- Epoxy and RTV Silicone (Recommended): Provides best encoder accuracy and flatness. Hard epoxy is applied at one end (typically the benching pin end), and 100% Silicone RTV adhesive is applied around the entire outside edge of the scale to allow for thermal expansion.
- Double-sided Adhesive Tape: A simpler method where the scale is pressed firmly onto the mounting surface after aligning with benching pins.
- Orientation: Specific mounting orientations and tolerances are provided for both linear and rotary scales to ensure proper function.
- Evaluation Boards: Celera Motion offers evaluation PCBs (CE300-4-PCB, CE300-40-PCB, CE-40GC-PCB) to facilitate initial testing and design of custom PCBs.
- Output Signals: The encoder provides differential quadrature signals (A+, A-, B+, B-) and index signals (IW+, IW-). Sin+ is also available for alignment purposes. Recommended signal termination for RS-422 compatibility is detailed.
Maintenance Features:
- Handling: Follow standard ESD precautions at all times, especially prior to reflow soldering, as the damage threshold is 500 V. Avoid touching electrical pins without static protection. Do not allow pickup devices to touch the "Keep Out Zone" on the sensor, as scratches can affect performance.
- Cleaning: Scales should be cleaned using nitrogen, clean air, or a similar gas for general particle removal. For contamination removal, use a lint-free cleanroom wipe or cotton swab dampened with isopropyl alcohol or acetone. Handle scales by the edges and avoid scrubbing.
- Troubleshooting: A dedicated section provides guidance for common issues such as the ChipEncoder not powering on, alignment problems, and evaluation PCB malfunctions. It directs users to check power supply, signal levels, and mechanical alignment.
- Service: The MicroE encoder is not designed for user service. Any maintenance procedures, such as cleaning, must be performed with the encoder turned off. Do not insert reflective surfaces into the beam path when the encoder is powered.
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