Rotary Encoders Technical Guide Explanation of Terms Resolution Maximum Response Frequency The pulse count of an incremental signal output when the shaft revolves once, or the absolute address count. The maximum frequency at which the signal can respond. Rise and Fall Times of Output Output Phase The elapsed time from a 10% to 90% change in the output pulse. The output signal count for an Incremental Encoder. There are 1phase models (phase A), 2-phase models (phase A, phase B), and 3phase models (phase A, phase B, and phase Z). The phase Z is an origin signal that is output once a revolution. 90% 10% 90% 10% Rise time Fall time Output Phase Difference When the shaft is rotated, this is the time difference between the rise or fall of the phase A and phase B signals, expressed as a proportion of the period of one signal, or as an electrical angle where one signal period equals 360°. The difference between phase A and phase B as an electrical angle is normally 90°. Phase A Phase B Difference between output phases 90˚ 90˚ 360˚ CW The clockwise direction of rotation. Viewed from the end of the shaft, the shaft rotates clockwise. With an Incremental Encoder, phase A normally leads phase B in this rotation direction. With an Absolute Encoder, this is the direction of code increase. The reverse of CW rotation is counterclockwise (CCW) rotation. CW CCW Output Circuit (1) Open-collector Output An output circuit where the emitter of the output circuit transistor is the common and the collector is open. (2) Voltage Output An output circuit where the emitter of the output circuit transistor is the common and a resistor is inserted between the collector and the power supply to convert the output from the collector to a voltage. (3) Line-driver Output An output method that uses a special IC for high-speed, longdistance data transmission that complies with the RS-422A standard. The signal is output as a differential secondary signal, and thus is strong with respect to noise. A special IC called a line receiver is used to receive the signal output from a line driver. (4) Complementary Output An output circuit with two output transistors (NPN and PNP) on the output. These two output transistors alternately turn ON and OFF depending on the high or low output signal. When using them, pull up to the positive power supply voltage level or pull down to 0 V. The complementary output allows flow-in or flow-out of the output current and thus the rising and falling speeds of signals are fast. This allows a long cable distance. They can be connected to open-collector input devices (NPN, PNP). Starting Torque Output Duty Ratio This is the ratio of the duration of high level during one period to the average period of pulse output when the shaft is rotated at a constant speed. Output duty ratio: H L High level time (T2) The torque needed to rotate the shaft of the Rotary Encoder at startup. The torque during normal rotation is normally lower than the starting torque. A shaft that has a waterproof seal has a higher starting torque. T2 T1 Pulse period (T1) 4 Rotary Encoders Technical Guide Moment of Inertia Absolute Code This expresses the magnitude of inertia when starting and stopping the Rotary Encoder. (1) Binary Code A pure binary code, expressed in the format 2n. Multiple bits may change when an address changes. (2) Gray Code A code in which only one bit changes when an address changes. The code plate of the Rotary Encoder uses gray code. (3) Remainder Gray Code This code is used when expressing resolutions with gray code that are not 2n, such as 36, 360, and 720. The nature of gray code is such that when the most significant bit of the code changes from 0 to 1 and the same size of area is used for both the larger value and the smaller value of objects, the signal only changes by 1 bit within this range when changing from the end to the beginning of a code. This enables any resolution that is an even number to be set with gray code. In this case, the code does not begin from 0, but from an intermediate code, and thus when actually using a code it must first be shifted so that it starts from 0. The example in the code table shows 36 divisions. For the change from address 31 to 32, the code extends from address 14 to 49 when 18 addresses each are taken for the objects. When changing from address 49 to 14, only one bit changes, and we can see that the characteristic of gray code is preserved. By shifting the code 14 addresses, it can be converted to a code that starts from address 0. (4) BCD Binary Coded Decimal Code. Each digit of a decimal number is expressed using a binary value. Shaft Capacity This is the load that can be applied to the shaft. The radial load is the load that is perpendicular to the shaft, and the thrust load is the load in the direction along the shaft. Both are permitted on the shaft during rotation, and the size of the load affects the life of the bearings. Ambient Operating Temperature The ambient temperature that meets the specifications, consisting of the permitted values for the external air temperature and the temperature of the parts that contact the Rotary Encoder. Ambient Storage Temperature The ambient temperature when the power is OFF that does not cause functional deterioration, consisting of the permitted values for the external air temperature and the temperature of the parts that contact the Rotary Encoder. Degree of Protection The level of protection against penetration of foreign objects from outside the Rotary Encoder. This is defined in the IEC60529 standard and expressed as IPXX. The degree of protection against oil is specified by OMRON standards, and is expressed as oil-proof construction or oil resistance. Serial Transmission In contrast to parallel transmission where multiple bits of data are simultaneously output, this method outputs data serially on a single transmission line, enabling the use of fewer wires. The receiving device converts the signals into parallel signals. 5 Rotary Encoders Technical Guide Hollow Shaft The rotating shaft is hollow, and the drive shaft can be directly connected to the hole in the hollow shaft to reduce the length along the direction of the shaft. A leaf spring is used as a buffer to absorb vibration from the drive shaft. Metal Disk The rotating slit disk in the Encoder is made of metal for higher shock tolerance than glass. Due to slit machining limitations, the metal disk cannot be used for high-resolution applications. Servo Mount A method of mounting the Encoder in which a Servo Mounting Bracket is used to clamp down the flange of the Encoder. The position of the Encoder in the direction of rotation can be adjusted, and thus this method is used to temporarily mount the Encoder to adjust the origin. Refer to Accessories. Absolute Code Table Decimal 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 Binary 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 BCD Gray remainder 14 Gray 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 6 Rotary Encoders Technical Guide Interpreting Engineering Data Bearing Life Cable Extension Characteristics Ws: 20N Ws: 25N Wr Encoder 4 3 Ws Shaft Wr: Radial load Ws: Thrust load Ws:30N 28 1.4 24 1.2 20 1.0 16 0.8 12 0.6 2 8 Ws:40N 0.4 V OL 1 4 10 20 1 30 40 50 Radial load Wr (N) 0.2 t LH 0 0 Output residual voltage VOL (V) 5 Output rise time tLH (µs) E6B2-CWZ6C Life (x 109 rotations) E6B2-C 2 5 10 20 0 50 100 200 Cable length (m) Measurement Example Power supply voltage: 5 VDC Load resistance: 1 kΩ (Output residual voltage is measured at a 35 mA load current.) Cable: Special Cable • This graph shows the relationship between mechanical life and the load applied to the shaft. • The size of the load during rotation affects the life of the bearings. • This graph shows the effect of the output waveform if the cable is extended. • Extending the cable length not only changes the startup time, but also increases the output residual voltage. Operating Procedure and Data Peripheral Device Connectability Yes: Connection possible. No: Connection not possible. Incremental Encoders Peripheral device EtherCATHigh-speed compatible Counter Unit Encoder Input Terminal Digital Counter Self-powered Tachometer Frequency/ Rate Meter Up/Down Counting Meter Period Meter Direction Detection Unit SYSMAC Pulse I/O Module ∗ H7BX-A H7CX-A@-N H7BX-AW H7CX-R@-N H7ER-N K3HB-R K3HB-C K3HB-P E63-WF5C CJ2M-CPU1@/ CPU3@ + CJ2M-MD21@ C@-CT@ GX-EC02@@ No No No No No No No Yes No E6D-CWZ2C Yes Yes Yes Yes Yes Yes No Yes No E6F-CWZ5G Yes Yes Yes Yes Yes Yes Yes Yes Yes E6A2-CS3E E6A2-CW3E E6A2-CWZ3E E6B2-CWZ3E E6H-CWZ3E E6C2-CWZ3E E6C3-CWZ3EH Yes Yes Yes Yes Yes Yes No Yes No E6A2-CS3C E6A2-CW3C E6A2-CWZ3C E6A2-CS5C E6A2-CW5C E6B2-CWZ6C E6H-CWZ6C E6C2-CWZ6C E6C3-CWZ5GH Yes Yes Yes Yes Yes Yes Yes Yes Yes E6B2-CWZ1X E6H-CWZ3X E6C2-CWZ1X E6C3-CWZ3XH No No No No No No Yes Yes Yes E6B2-CWZ5B E6C2-CWZ5B No No Yes No Yes No No No No Rotary Encoder model Model E6D-CWZ1E E6J-CWZ1E * Supported by CJ2M CPU Unit with unit version 2.0 or later. 7 Rotary Encoders Technical Guide Absolute Encoders Peripheral device Rotary Encoder model Cam Positioner Model SYSMAC Programmable Controller H8PS CPM1A E6CP-AG5C E6C3-AG5C No Yes E6CP-AG5C-C E6C3-AG5C-C E6F-AG5C-C Yes No E6F-AB3C No Yes E6F-AB3C-C No No Requires separate power supply for Encoder. Requires separate power supply for Encoder. Example of Connection with H7BX-AW Self-powered Tachometer CP1H CP1L CP1E DC Input Unit Yes Yes Yes Yes No No No No Yes Yes Yes Yes No No No No • NPN Open-collector Outputs Example of E6A2-CS3C, E6A2-CS5C Applicable E6A2-CW3C, E6A2-CW5C Models E6C2-CWZ6C, E6F-CWZ5G +12V 9 K3HB-C Up/Down Counting Meter 10 11 12 13 14 A Brown E6A2 Black 15 17 Blue 0V 16 18 E6C2-CWZ6C 1 2 3 4 5 6 POWER +12V 7 Example of Connection with H7BX-A Digital Counter Example of E6A2-CW3E Applicable E6C2-CWZ3E, E6C3-CWZ3EH, Models E6F-CWZ5G Black 9 A 17 16 18 Blue 0V 2 E K3HB-C Up/Down Counting Meter 10 11 12 13 14 15 1 D Example of E6A2-CS3E, E6A2-CW3E Applicable E6C2-CWZ3E Models White E6A2-CW3 C • Voltage Outputs +12V 8 B 1 2 3 4 5 6 0V Phase A Phase B H7BX-AW Self-powered Tachometer Brown Requires separate power supply for Encoder. Example of Connection with K3HB-C Up/Down Counting Meter Example of E6A2-CS3E 10P/R, 60P/R Applicable E6C2-CWZ3E, E6F-CWZ5G 600P/R Models E6C3-CWZ3EH 10P/R, 60P/R, 600P/R 8 Requires separate power supply for Encoder. 3 4 5 6 7 H7BX-A Digital Counter E6C2-CWZ3E POWER +12V B C D E 1 2 3 4 5 6 0V Phase A 8 Rotary Encoders Technical Guide Example of Connection with CJ1W-CT021 High-speed Counter Unit in Programmable Controller Example of E6A2-C, E6B2-C, E6C2-C, E6H-C Applicable E6F-CWZ5G, Models (1) E6D (open-collector output) Encoder with NPN Open-collector Output (5/12/24 VDC) Example of E6B2-CWZ5B Applicable E6C2-CWZ5B, E6C3-CWZ5GH Models (2) Encoder with PNP Open-collector Output (5/12/24 VDC) High-speed Counter Unit (CN1) Black (phase A) Encoder White (phase B) Orange (phase Z) Example: E6C2-CWZ6C NPN Open-collector Outputs Brown (+Vcc) B9 (phase A, 24 V) A8 (phase A, 0 V) B11 (phase B, 24 V) A10 (phase B, 0 V) B13 (phase Z, 24 V) A12 (phase Z, 0 V) Counter 1 Blue (0 V) (COM) High-speed Counter Unit (CN1) Black (phase A) Encoder Orange (phase Z) Example: E6C2-CWZ5B PNP Open-collector Output B9 (phase A, 24 V) A8 (phase A, 0 V) B11 (phase B, 24 V) A10 (phase B, 0 V) B13 (phase Z, 24 V) A12 (phase Z, 0 V) Counter 1 Brown (+Vcc) Blue (0 V) (COM) 0V +24V Power supply: 24 VDC 0V +24V Power supply: 24 VDC Note: Connections are as follows if the Encoder power supply is 5 V or 24 V. Phase A + 5-V power supply ➝ A19, 24 V ➝ B20 Phase B + 5-V power supply ➝ A17, 24 V ➝ B18 White (phase B) Note: Note: Connections are as follows if the Encoder power supply is 5 V or 24 V. Phase A + 5-V power supply ➝ A19, 24 V ➝ B20 Phase B + 5-V power supply ➝ A17, 24 V ➝ B18 Example of E6B2-CWZ1X, E6C2-CWZ1X Applicable E6C3-CWZ3XH, E6H-CWZ3X Models (3) Encoder with Line-driver Output (RS-422) High-speed Counter Unit (CN1) Encoder Example: E6B2-CWZ1X with Line-driver Output Black (phase A +) Black/red (phase A -) White (phase B +) White/red (phase B -) Orange (phase Z +) Orange/red (phase Z -) Brown (5 VDC) B15 (phase A, line driver +) A15 (phase A, line driver -) B17 (phase B, line driver +) A17 (phase B, line driver -) B19 (phase Z, line driver +) A19 (phase Z, line driver -) Counter 2 Blue (0 V) (COM) 0V +5V Power supply: 5 VDC 9 Rotary Encoders Technical Guide Example of Connection with CJ2M-CPU1@/CPU3@ + CJ2M-MD21@ SYSMAC Pulse I/O Module Example of E6A2-CWZ5C, E6C2-CWZ6C, Applicable E6C3-CWZ5GH, E6F-CWZ5G Models CJ2M Pulse I/O Modules (Phase Difference Input Mode) Black Phase A Encoder (Power supply: 24 VDC) White Phase B Example: E6B2-CWZ6C NPN Open-collector Output Phase Z Orange +Vcc Brown 25 High-speed counter 0: Phase A, 24 V 29 High-speed counter 0: Phase A, 0 V 26 High-speed counter 0: Phase B, 24 V 30 High-speed counter 0: Phase B, 0 V 8 High-speed counter 0: Phase Z, 24 V 12 High-speed counter 0: Phase Z, 0 V CJ2M-CPU1@/CPU3@ + CJ2M-MD21@ 0V(COM) Blue Power supply 24 VDC 0V +24V • Up to two Pulse I/O Modules can be mounted to a CJ2M CPU Unit with unit version 2.0 or later. Each Pulse I/O Module allows you to use six inputs (IN8, IN9, IN3, IN6, IN7, and IN2) to directly input pulses from rotary encoders for application in built-in high-speed counters. • The response speed is 60 kHz for single phase and the phase difference (multiplier of 4) is 30 kHz. Counting can be performed from 0 to 4,294,967,295 pulses in incremental mode and from 2,147,483,648 to 2,147,483,647 in incremental/decremental mode. • Operating modes for the high-speed counter are set in the PLC Setup. <Count Mode> Phase difference input mode Incremental/decremental counting is performed using the phase difference between phases A and B (4-times multiplier constant). Incement/ decrement pulse input mode Incremental/decremental counting is performed using phase A as the incremental pulse input and phase B as the decremental pulse input. Pulse and direction input mode Incremental/decremental counting is performed using phase A as the pulse input and phase B as the direction signal (i.e., incremental/decremental). Incremental pulse input mode <Value range mode> Linear mode Counting is performed within the range of the upper limit and lower limit. Ring mode Counting is performed by looping the input pulse within the set range. <Reset Method> Phase Z and software reset If software reset is ON, the present value will be reset when the phase-Z input turns ON. Software reset The present value will be reset when software reset turns ON. <Output Method> Incremental counting is performed using phase A only. Target value comparison Up to 48 target values can be set. When the present value reaches a target value, the specified subroutine is executed. Range comparison Up to 8 ranges (upper and lower limits) can be set. When the present value enters a range, the specified subroutine is executed. Example of E6B2-CWZ1X, E6C2-CWZ1X, Applicable E6C3-CWZ3XH, E6H-CWZ3X with Line-driver OutModels put CJ2M Pulse I/O Modules Black Black (striped) Encoder Example: E6B2-CWZ1X with Line-driver Output White White (striped) A+ AB+ B- Z+ Orange Orange (striped) Z- Brown Blue DC5V (Phase Difference Input Mode) 27 High-speed counter 0: Phase A, LD+ 29 High-speed counter 0: Phase A, LD- 28 High-speed counter 0: Phase B, LD+ 30 High-speed counter 0: Phase B, LD- 10 High-speed counter 0: Phase Z, LD+ 12 High-speed counter 0: Phase Z, LD- CJ2M-CPU1@/CPU3@ + CJ2M-MD21@ Power supply: 5 VDC +5V 0V 0V 10