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Incremental Encoder Options and Features
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Output Types |
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| Single - a single square wave output (A) with the specified counts per revolution regardless of which direction the shaft is rotating (also called unidirectional output). |  |
| Quadrature - a 90º displacement between two similar edges of two-phased outputs generated by a common input. In other words, two square wave outputs (A and B) having the same number of counts per revolution are in quadrature relation to each other if A leads B by 90° for clockwise rotation and B leads A by 90º for counter-clockwise rotation. The pulse outputs indicate the amount of shaft rotation, and the A / B phase difference indicates the direction of rotation. This output type is compatible with any control device that accepts quadrature inputs. |  |
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Zero Marker - combined with either the Single or Quadrature outputs, output Z provides a zero reference or index pulse occurring once per revolution and having a pulse width, when the output is high, approximately equal to a single pulse on output A. An inverted zero reference (NZ) is also available that has a low value once per revolution and is approximately equal to a single pulse on output A. |
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| Direction Indicator - a digital output that indicates the direction of rotation: the output is high when rotating in one direction and low when rotating in the other direction. See the M189 Datasheet. |  |
| Minimum Speed Indicator - a digital output that turns "on" when the encoder shaft exceeds a predetermined revolution per minute (RPM) and turns "off" when the RPM is less than the predetermined RPM value. See the M140 Datasheet. |
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| Dual - two independent square wave outputs (A and B), and the counts per revolution on A can be different than the counts per revolution on B. A can be a value from 1 through 1200 and B can be from 1 through 360. |  |
| Triple - three independent square wave outputs (A, B, and C) each having from 1 to 360 counts per revolution. |  |
Output Circuits |
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| Push/Pull - A general-purpose circuit capable of either sourcing or sinking up to 50ma of current per output, and is compatible with most motion control equipment. |  |
| Current Sinking - A general-purpose circuit capable of either sourcing or sinking up to 50ma of current per output, and is compatible with most motion control equipment. |  |
| Current Sourcing - A PNP transistor with a pull-down resistor and capable of sourcing 50ma of current per output. This type of encoder output is used with a PLC or other control device that sinks current. The encoder uses the PNP transistor to represent binary logic by optionally switching current through the output to the PLC. |  |
| Open Collector - An NPN transistor without a pull-up resistor and capable of sinking 50ma of current per output. An external pull-up resistor must be used. This output type is typically used when the encoder and the device receiving the encoder's output pulses are operating at different supply voltages. Caution: the output must not be pulled up more than 30 VDC, and both supplies must reference the same common. |  |
| RS422 Differential Line Driver - An RS422 differential line driver (MC3487 or compatible device) that generates 5vdc complementary outputs: A / -A, B / -B, and Z / -Z as needed. The encoder must be operated at 5 vdc or be equipped with an internal regulator (see supply voltages: 5R or 8-30). |  |
| 4469 Line Driver - capable of driving highly capacitive, inductive, or resistive loads with the ability to source or sink up to 200ma current per output. The high output voltage will nominally be the same as the supply voltage. If the supply voltage exceeds 18 VDC then the encoder must be equipped with an internal regulator (see supply voltages: 5R, 12R, 15R, or 8-30). In this case, the high output voltage will be 5, 12, or 15 VDC depending on the supply voltage option. |  |
| 7272 Differential Line Driver - a general-purpose output able to operate at 5vdc or 8-30vdc, capable of sourcing or sinking 50ma, and able to produce single-ended (A, B, Z push/pull) or complementary (+A/-A, +B,-B, +Z/-Z differential line driver) outputs. The output voltage level is approximately equal to the supply voltage. The outputs are reverse voltage, over-voltage, and short circuit protected for one minute. | |
| 7273 Open Collector - An improved open collector output that includes reverse voltage, over-voltage, and short circuit protection. Capable of sinking 50ma of current per output. An external pull-up resistor must be used. This output type is typically used when the encoder and the device receiving the encoder's output pulses are operating at different supply voltages. Caution: the output must not be pulled up more than 30 VDC, and both supplies must reference the same common. | |
| SN74265 Line Driver - Must be operated at 5 VDC. The encoder must be operated at 5 VDC or be equipped with an internal regulator (see supply voltages: 5R or 8-30). | |
| Triac - an optically isolated triac capable of directly driving most 120 vac loads up to 2 amps (rms) without the use of any external components. It includes a zero crossing detector that switches the triac on and off synchronously at near zero volts. The triac output can be directly interfaced to AC inputs on most PLCs and other motion controllers. Only available with 120 vac supply voltage. (120ACT Datasheet) |  |
Anti-Jitter Option |
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The “Anti-Jitter” option was designed for conveyor and web systems, and especially material handling sortation systems, that require continuous and accurate measurement of the web's movement even if the system must be stopped and restarted without reset. These applications typically use a single output encoder or PPI for tracking the webs movement. When the web stops, and if there is sufficient vibration or back-and-forth movement, then the encoder output could oscillate, appearing as if the web were actually moving. This condition is referred to as "dither".
All Photocraft encoders are designed with a certain degree of built-in hysteresis that eliminates this problem in most applications. Conveyor and web application requirements often exceed the normal hysteresis capability of encoders. The “Anti-Jitter” feature further eliminates dither by increasing the pulse hysteresis using one of two methods depending on the model:
- Standard Anti-Jitter: Hysteresis is increased to ½ of the pulse width. For example, a 24 counts per revolution output would have 7.5° hysteresis (i.e. 360° ÷ 24 × ½ ).
- Enhanced Anti-Jitter: Hysteresis is increased to a percentage of a shaft revolution or multiple revolutions (depending on the model). That is, the encoder will generate pulses as long as it continues to rotate in one direction. If the direction reverses then pulse output ceases until the encoder returns to its original direction of rotation and to its position before reversing. If the reverse direction continues beyond the maximum hysteresis then the encoder resets and begins generating pulses in the reverse direction. (See the model-specific datasheet or M139 Datasheet.)
For Enhanced Anti-Jitter that only generates pulses for one direction of rotation determined by a switch setting see the M180 Datasheet.
For Enhanced Anti-Jitter with a maximum hysteresis of one rotation see the M233 Datasheet.
Supply Voltages |
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The following supply voltage options are available:
- DC voltages with ± 5% tolerance: 5, 12, 15, or 24 vdc
- DC voltage ranges:
| Designation | Supply Voltage Range (vdc) |
| 5-26 | 5 to 26 |
| 8-30 | 8 to 30 |
| 5R | 7 to 20 |
| 12R | 12 to 27 |
| 15R | 15 to 30 |
| 24R | 8 to 30 |
- 12 vdc Automotive Power option - encoder can be operated directly from an unfiltered 12 vdc automotive power system. (12vdc Automotive Datasheet)
- 120 vac Power option - some RG, RH, RJ, and RL encoder models can be powered directly from 120 vac. (120ACT Datasheet)
Counts Per Revolution |
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The number of 50/50 duty cycle, square wave pulses that are generated for each incremental encoder shaft revolution. The following counts per revolution are in stock. Other values up to 1350 are available with a nominal one-time charge.
- Any value from 1 through 360
- 375, 384, 397, 399, 400, 432, 436, 450, 475, 480, 500, 512, 560, 565, 600, 625, 635, 660, 720, 735, 750, 768, 800, 864, 900, 984, 1000, 1024, 1058, 1200, 1250, 1270, 1344
HS25 hollow shaft encoder:
- Any value from 1 through 360
- 375, 384, 397, 399, 400, 432, 436, 450, 475, 480, 500, 512, 560, 565, 600
Programmable encoders can generate any one of the factory-programmed sets of counts per revolution by configuring switches on the encoder at installation time. Fractional values are also available with programmable encoders, for example, 2.5 counts per revolution.
High-resolution programmable encoders are available with up to 6,000 counts per revolution.
Centimeters Per Revolution |
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A model RH-P wheeled encoder equipped with standard 30-centimeter measuring wheels, or the R21-P and R22-P equipped with 20-centimeter wheels can generate pulses based on specific distance traveled, measured in centimeters. This eliminates the necessity for the engineer to translate to counts per revolution, and to search for the appropriate size measuring wheel.
For example, with this feature the model RH-P300M wheeled encoder could generate a pulse for any predefined unit of length to the nearest millimeter up to 1 meter. The encoder's internal micro-controller maintains the necessary counters based on the internal code disk resolution and the 30-centimeter measuring wheel.
Programmable Encoder Programs |
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The following table shows all currently available programmable encoder programs, the associated program features, and the applicable encoder models. Many other customer-specific programs exist. If you do not see what you want then contact us.
- Click the program name to see a sample datasheet.
- The Fixed output circuit is factory configured to either Push/Pull or Open Collector output.
- Selectable output circuit is either Current Sinking, Current Sourcing, Open Collector, or Push/Pull.
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Program Name |
Output Type optionally with Anti-Jitter | Output Circuit | Selectable counts per revolution | Encoder Model | |||||
| Selectable | Fixed | HS20-P HS25-P |
R20-P R22-P |
RH-P | RL-P HRL-P |
RS-P HRS-P |
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| P.125AJ | Single with anti-jitter | X | .125 through 8.000 in steps of .125 | X | X | X | X | X | |
| P144AJ | Single with anti-jitter | X | 1, 2, 3, 4, 5.236, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144 | X | X | ||||
| P144AJ | Single with anti-jitter | X | 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144 | X | X | X | |||
| P144AJB | Single with anti-jitter and direction | X | 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144 | X | X | X | X | X | |
| P144AJZ | Single with anti-jitter and zero marker | X | 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144 | X | X | X | X | X | |
| P1500QB | Quadrature with direction | X | 30, 240, 300, 360, 400, 480, 600, 1500 | X | X | X | X | X | |
| P20EAJ | Single with enhanced anti-jitter | X | Millimeters/pulse: 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, 100 (when used with MW-20 wheel) |
X | X | X | X | X | |
| P240AJ | Single with anti-jitter | X | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 36, 40, 48, 60, 80, 120, 192, 240 | X | X | ||||
| P240AJ | Single with anti-jitter | X | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 36, 40, 48, 60, 80, 120, 240 | X | X | X | |||
| P240AJB | Single with anti-jitter and direction | X | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 36, 40, 48, 60, 80, 120, 240 | X | X | X | X | X | |
| P240Q | Quadrature | X | 1, 2, 3, 3.333*, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120 | X | X | X | X | X | |
| P256 | Single | X | 4 through 256 (every 4th value) | X | X | X | X | X | |
| P270AJ | Single with anti-jitter | X | 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 54, 60 | X | X | ||||
| P270AJ | Single with anti-jitter | X | 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 54, 60 | X | X | X | |||
| P270AJB | Single with anti-jitter and direction | X | 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 54, 60 | X | X | X | X | X | |
| P300AJQ | Quadrature with anti-jitter | X | 60, 75, 100, 120, 150, 300 | X | X | X | X | X | |
| P300M | Single with anti-jitter | X | .1, .5, 1, 2, 3, 4, 5, 6, 6.6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50, 75, 100 (centimeters per pulse using MW-30 measuring wheel) |
X | X | ||||
| P300Q | Quadrature | X | 2, 3, 4, 5, 10, 15, 20, 25, 30, 50, 60, 75, 100, 150, 300 | X | X | X | X | X | |
| P436AJ | Single with anti-jitter | X | 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 54, 436 | X | X | ||||
| P480AJ | Single with anti-jitter | X | 5, 240, 480 | X | X | X | X | X | |
| P600AJ2 | 2 identical outputs with anti-jitter | X | 200, 240, 300, 360, 400, 480, 600 | X | X | X | X | X | |
| P600AJB | Single with anti-jitter and direction | X | 200, 240, 300, 360, 400, 480, 600 | X | X | X | X | X | |
| P600AJQ | Quadrature with anti-jitter | X | 12, 24, 600, or 1200 / 2400 (dual output) | X | X | X | X | X | |
| P64AJ | Single with anti-jitter | X | 1 through 64 | X | X | X | X | X | |
| P64AJB | Single with anti-jitter and direction | X | 1 through 64 | X | X | X | X | X | |
| P64B | Single and direction | X | 1 through 64 | X | X | X | X | X | |
| P64Q | Quadrature | X | 1 through 64 | X | X | X | X | X | |
| P8EAJ | Single with enhanced anti-jitter | X | Pulses/foot: 1, 2, 3, 4, 6 Pulses/inch: 1, 2, 3, 4, 5, 10, 16, 20 (when used with MW-8 wheel) |
X | X | X | X | X | |
Shaft Options |
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Following are the currently available shaft diameters. Nominal diameters are shown with actual diameters in parentheses.
| Standard Diameter | Optional Diameters |
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3/8" (.3744" to .3747") |
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Hollow Shaft Options |
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Currently stocked hollow shafts are shown below. Call for information about others.
HS20 hollow shaft encoder:
| Standard Inside Diameters | Optional Inside Diameters |
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Any diameter less than 5/8" or 16mm |
HS25 hollow shaft encoder:
| Standard Inside Diameters | Optional Inside Diameters |
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Any diameter less than 3/8" or 10mm |
HS30 hollow shaft encoder:
| Standard Inside Diameters | Optional Inside Diameters |
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Any diameter less than 1-2/8" or 28mm |
HRL and HRS hollow shaft encoder. The shaft bore on these models is .75" (19mm) deep.
| Standard Inside Diameters | Optional Inside Diameters |
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Any diameter less than 1" or 25mm |
Custom Models |
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Photocraft manufactures many modified versions of our standard products to meet specific application requirements. Custom versions of our standard products could include any of the following:
- Shaft lengths, diameters, or modifications such as flats and keyways.
- Mounting configurations and adapters.
- Circuit options, such as custom output types or output circuits
- Software features and counts-per-revolution code sets (programmable encoders only)
- Cables and connectors
- Private labeling
If you see a feature available on one encoder model, it is probably available on other encoder models even if not documented.
For economical solutions to your special encoder needs, allow our engineers to work with you to design a product that exactly meets your requirements.
Short Circuit Protection |
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Protects the encoder outputs from damage caused by short circuits to either ground or +V, or from the excessive current draw. Without this feature, either one of these conditions would permanently damage the encoder output. With this feature, the encoder will be protected from short-circuits or over-current conditions, and in most cases will function normally when the condition is removed.
ESD Protection |
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Static electricity is especially prevalent in material handling conveyor applications, and can easily cause permanent damage to the encoder. This feature protects the encoder circuitry and output transistors from high voltage transients to at least 8 K-volts direct and 25 K-volts air discharge to either the encoder housing or cable.
Enhanced Surge Protection |
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Protects the encoder against surges caused by lightning strikes on the power mains. It is recommended, and required for CE marking, under the following conditions:
- the encoder cable exceeds 30 meters (100 feet), or
- part of the cable leaves the building (including lines of outdoor installations).
CE Marking |
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Encoders that are marked with 
have been certified against the relevant EMC Directive requirements as defined in harmonized standard EN 61326. CE marking applies to the combined encoder and specially constructed cable. Use of non-Photocraft cables voids the CE mark. Encoders with cables longer than 30 meters (100 feet) require the surge protection feature. Please contact us for additional information about the detailed CE test specifications, and the encoder models that have been certified.