Internal Encoded Rotary Encoders Introduction Rotary Encoders have been used in factory automation (FA) for quite some time. The most representative are industrial robots; robotic manipulators have two-axis, multi-axis, but All robots actuate the robot arm. In the structure of the robot, the source of kinetic energy for all robotic arms is the motor. The main sources of kinetic energy for most FA and OA equipment are also motors; and motors are controlled in the form of different instructions. The control method of the motor operation has only a certain period of time to run at a certain speed, there are complex and irregular operation, there are multiple axes running at the same time, etc., thus forming a variety of operating conditions of the machinery and equipment.
The control of the motor is usually speed control and displacement (selection) control, the control method is different with the type of motor. For example, stepper motor movement control, in the open-loop control state, the rotation angle (number of turns) is synchronized with the number of control pulses, unless the special circumstances such as out of step, it should be able to move synchronously. In addition to the stepper motor, it is very difficult to detect the rotation of other motors if no signal feedback is required to achieve precise control. In short, the speed control of the motor speed can be represented by the control amount and feedback to the control circuit to maintain the motor at a certain speed or stop at a certain position. In general, this rotation feedback amount is detected by a rotary encoder.
The inner photoelectric control photoelectric encoder principle photoelectric encoder is a sensor that converts the mechanical geometric displacement on the output shaft into an electrical pulse or an electronic digital quantity through photoelectric conversion. This is currently the most widely used sensor, and the photoelectric encoder is composed of a grating disk and a photoelectric detection device. The grating plate is a fan-shaped transparent channel that is evenly opened on a circular plate with a certain diameter.
Since the photoelectric encoder and the motor are coaxial, when the motor rotates, the grating disk rotates synchronously with the motor, and a detection device composed of an electronic element such as a light emitting diode detects and outputs a plurality of pulse signals, and the number of output pulses can be calculated within a certain period of time. Reflects the current motor speed. In addition, to determine the direction of rotation, the encoder can also provide pulse signals with electrical phase differences of 90 degrees.
The inner-incremental incremental encoder incremental encoder directly outputs three groups of square-wave pulses A, B, and Z phases using the principle of photoelectric conversion; A and B groups of pulses have a phase difference of 90 degrees and a Z-phase of one pulse per revolution. Positioning at the benchmark. Its advantage is that the principle of the structure is simple, the mechanical average life can be more than tens of thousands of hours, anti-interference ability, high reliability, suitable for long-distance transmission. The disadvantage is that the absolute position information of the shaft rotation cannot be output.
Internal dense control shaft encoder installation precautions
• Elastic soft connection between the encoder shaft and the output shaft of the customer end to avoid the damage of the encoder shaft and code wheel caused by the user's shaft movement or jump.
• Pay attention to the permissible shaft load during installation.
• The difference between the encoder shaft and the user output shaft should be less than 0.20mm, and the declination from the shaft should be less than 1.5°. It is forbidden to hit and hit the collision during installation so as not to damage the shaft system and the code wheel.
Internal Encoder Usage Notes • The encoder is a precision sensor. When subjected to a large impact, internal damage may result. So the encoder cannot drop, hammer or over-collision.
• Do not connect or remove the signal cable while it is live, as this may cause a short circuit and damage the encoder and the system.
• Do not test the encoder with a megohmmeter to avoid damage.
• Do not disassemble the encoder yourself to avoid damage.
• Incorrect wiring will damage the internal circuit. Please confirm it carefully after wiring.
Internal Encoder Hollow Shaft Installation Precautions
• To avoid rigid connection to the encoder, use an elastic connection plate provided or specified by the encoder manufacturer.
• The encoder should be gently pushed into the quilt shaft during installation. It is forbidden to use a hammer to knock the shaft and the code wheel.
• When using it for a long period of time, check if the plate spring is loose with respect to the encoder; if the screws securing the encoder are loose.
Internal Encoder Electrical aspects • The ground wire should be as thick as possible, generally larger than Φ3.
• The output lines of the encoder should not overlap each other to avoid damage to the output circuit.
• Do not connect the signal line of the encoder to the DC power supply or AC current to avoid damaging the output circuit.
• The motor and other equipment connected to the encoder should be well grounded and should not have static electricity.
• Use shielded cables when wiring.
• Before starting the machine, check carefully whether the product specification and the encoder model are correct and the wiring is correct.
• For long-distance transmission, signal attenuation factors should be taken into account, and output methods with low output impedance and strong anti-interference capability should be selected. Avoid using in strong electromagnetic wave environment.
• Long-line output In the case where long-term signal transmission is required, wire resistance should be used; the capacitance is low; and the cable is strong against interference. To reduce the line resistance, waveform distortion caused by line capacitance and resistance to environmental interference. And choose the dual push-pull type (F) or line drive type (LY) output encoder, transmission line more than 20 meters should be used double shielded cable.
• The encoder cable must not be placed in the same conduit as the power cable, and the wiring should be kept as parallel as possible to the power line. The grounded shield of the encoder socket is internally connected to the encoder housing.
• When ordering an incremental encoder, please specify in detail the selected model, number of output pulses per revolution, power supply voltage, outlet method, signal output method, and note whether the mechanical mounting dimensions of the selected model will meet your requirements.
Internal Encoder Environment Requirements • The encoder is a precision instrument. Be aware of the absence of vibration sources and electromagnetic interference sources when using the encoder.
• Pay attention to the protection level of the encoder when using it. It is not a leakproof structure. When using or storing, do not splash water or oil. If necessary, install a protective cover on the encoder.
• Please note that the actual use of the ambient temperature and humidity is within the required range of encoder use.