What is an ENCODER. An electronic component that generates an ON and OFF output signal periodically.

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Earl Barber
5 years ago
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1 Encoder

2 2 What is an ENCODER ENCODER Make signal or code. An electronic component that generates an ON and OFF output signal periodically.

The Output is different between Encoder and Potentiometer though the shape is very similar.

3 Difference between Encoder and Potentiometer An incremental encoder works by providing an A and a B pulse output to an external counting electronics. The Output is different between Encoder and Potentiometer though the shape is very similar. Encoder Output signal of encoder is repetition of ON/OFF. Potentiometer Output signal of Potentiometer is continuous voltage change. Output Digital Output Output Analogue Output Travel Travel

4 4 Variety of Encoder Fundamental structure Feature Contact type Mechanical contact It can be composed of the low price comparatively. Non-contact type Magnetic Optical It s strong for using in dirty environment. Fine pattern is possible because of the optical process. Encoder Incremental type Absolute type Operation is counted as a quantity of pulse, and a relative position is detected. That position where it moved is detected as an absolute code.

5 Variations of Encoders Incremental type, ABC SW type and Absolute type. Incremental Encoder (2 output) ABC SW (3 output) Absolute Encoder (Gray code/binary code) P/N EC09E EC11E etc EC11EH EC35AH etc EC20A EC45A etc Output Signal OFF ON OFF ON OFF ON Click Position Reading method Relative position output. Method of reading by comparing the relation between two output signals. Relative position output. Method of reading by judging the output order of three different output signals. Absolute position output. Different output at each positions Feature 2 circuits only for reading signal. Reading method is complex. No misreading due to chattering noise. Absolute position output. Different output at each Positions. Risk for misreading due to chattering noise. Need 3 circuits for reading signal. Need more than 3 circuits for reading signal.

6 Product structure of Encoder Insulated shaft Metal shaft Encoder Rotary Hollow shaft Hollow shaft Magnetic Multi control

7 Pulse definition, Resolution and Phase difference B signal 7 Pulse definition : 1 pulse form 1cycle from ON to ON. Resolution : The number of the pulses which occurs by 1 turn. The higher solution is more numbers of the pulses. Phase difference : Shifting A signal and B signal is intentionally. This difference is called a phase difference. It judges the direction of the turn by measurement about whether the B signal is ON or OFF when the A signal becomes ON. 1 pulse H L H -90 Phase angle of pulse 180 L Turn resolution (p/r) = number of pulses 1 turn

8 How to use an Encoder (Incremental, phase gap = 90 ) When the Encoder is in click position, A phase is stable and B is changing output signal. 0:OFF 1:ON Click position when A phase is stable 1 pulse CW direction CCW direction A-C output B-C output Phase diff. A-C output 1 0 B-C output 1 Direction CW A changes 1 to 0 and B is 1 => CW direction CW CCW CCW When the output of A changes, the output of B indicates the direction.

9 How to use an Encoder (Incremental, phase gap < 90 ) When the Encoder is in click position, A phase and B phase is stable with same output signal. Click position when A/B phase is stable 1 pulse CW direction 0 A-C output 1 0 B-C output 1 Phase diff. Change Fix CCW direction The signal of Encoder is ON and OFF only. The IC recognizes 1 as ON and 0 as OFF. A-C output B-C output The encoder is turned in CW-direction when A changes first and A and B have the same phase(00 or 11) as starting points. When B changes first, CCW-direction is assumed. However it s not fixed at this stage. It s fixed when A and B phase return to the same phase (00 or 11) again. (It changes at click position.)

10 10 Chattering, Bounce and Sliding noise Brush Contact pattern on code disk Substrate OFF OUT-PUT SIGNAL Sliding noise (Minute disorder at ON) ON Bounce (Momentary OFF in ON) Chattering (Signal of ON,OFF in the boundary)

11 11 Example of recommendation filter circuit The influence of Chattering to the output signal is reduced by the filter circuit.

EC35 Ring Type Encoder For Oven Range RK09D RS H RS 1

12 Pot. and Encoder for Home Appliance For Washing Machine For Refrigerator EC12E EC18A Shaft Type Encoder EC21A EC28A EC35 Ring Type Encoder For Oven Range RK09D RS H RS 1 Potentiometer for Temp. control EC21A EC28A EC35 Ring Type Encoder 12

13 Oven Range EC21A EC28A EC35 Ring Type Encoder EC50A Whirlpool TOSHIBA SHARP 13

14 Encoder and Pot. for Automotive For Steering and Indicator Area For Audio and HVAC Area EC11J EC35B EC50A EC11 EC20A EC10E Encoder Encoder RK45C RK097 Potentiometer RK119 RK097 Potentiometer RKJXT RKJXM Multi Controller 14

15 End ALPS ELECTRIC CO., LTD.

Heavy torque and comfortable operation feel for encoder and potentiometer applications. Typical Specifications. Items. Rating 1mA 5V DC 0.

EC0A RK0 0mm Size Heavy torque and comfortable operation feel for encoder and potentiometer applications Typical Specifications Items Specifications Encoder Potentiometer Product Line Length of the configuration