Position Sensor Glossary

A

Absolute Encoder Technology

Absolute rotary encoders are capable of providing unique position values from the moment they are switched on. This is accomplished by scanning the position of a coded element. All positions in these systems correspond to a unique code. Even movements that occur while the system is without power are translated into accurate position values once the encoder is powered up again.

Analog Interface

Analog interfaces can be cost effective for simple control systems. Using point-to-point wiring, they are easy to implement for small networks (1-5 sensors). Analog installations are common in applications like vehicles, medical equipment and energy management.

ATEX (ATmosphere EXplosible)

ATEX-certified rotary encoders are designed to operate safely in atmospheres where there are potentially dangerous levels of explosive gases or dust.

B

Blind Hollow Flange

Blind Hollow Shaft Flanges (aka Hub Shafts) are designed so that the shaft does not pass completely through the encoder but rather resides inside the housing. clamping rings and set screws are used to mount the encoder on the shaft. Various anti-rotation tether options allow easy assembly to any motor or machine frame.

Binary Code (SSI)

Data representation that is most commonly left aligned. It starts with the MSB, which is the highest bit for a multiturn encoder.

C

CANopen Interface

CANopen is a Fieldbus protocol using CAN networks and CANopen Lift is a protocol for elevator applications.

CANopen Lift Interface

CANopen Lift is a fieldbus protocol for elevator applications. It is similar to CANopen and based using CAN networks.

CANopen Safety

The CANopen Safety framework for safety-relevant communication is an add-on to the CANopen application layer and communication profile.

Configuration Box UBIFAST

The UBIFAST configuration tool is used to configure the various parameters available in our IXARC programmable encoders.

Cable Connection Type

POSITAL encoders are available with cable exit in axial or radial direction with different cable lengths and different cable materials like PUR or PVC.

Connector Connection Type

POSITAL encoders are available with a wide range of different connectors in axial or radial direction.

Connection Cap Connection Type

Connection caps are a common solution for encoders with with fieldbus or Ethernet interface. Connection caps are suitable for daisy chain cabling and allow a convenient electrical installation and configuration.

Conflict Minerals

Conflict minerals are minerals mined in conditions of armed conflict and human rights abuses, notably in the eastern provinces of the Democratic Republic of the Congo, by the Congolese National Army and various armed rebel groups, including the Democratic Forces for the Liberation of Rwanda.

Certificates

Read more about Certificates & Statements

Communication Interfaces

Given the wide range of applications that come under heading “motion control”, there is clearly no single best solution for all problems. Industrial Ethernet offers advanced features that are extremely valuable to designers of large, complex factory systems. However, for smaller, more self-contained applications, simpler technologies such as fieldbus (CANopen, PROFIBUS) or point-to-point wiring (SSI, Bit-Parallel, or even Analog) have a place. POSITAL position and motion sensors, including IXARC rotary encoders, TILTIX inclinometers and LINARIX linear position sensors are available with a full range of communications interfaces.

Clamping Flange

Clamp flanges are the most versatile in assembly (i.e. clamping, use of front tapped holes, clamping discs). Clamp flanges can be installed in a variety of ways including flange adapters and mounting brackets. These typically have higher shaft loads available for applications.

CE marking is a mandatory conformity mark for all products sold on the European market. With the CE marking POSITAL declares that the product conforms with essential requirements of the applicable EC directives.

D

Document Archive

POSITAL provides a discontinued encoder guide with all current cross references.

Discontinued Products

Discontinued products are not available for purchase any more. We list the recommended products for replacement when possible.

DeviceNet

DeviceNet is a fieldbus system based on CAN networks and CIP protocol. DeviceNet is managed by ODVA, widely used in factory automation and available on many PLCs.

E

EtherNet/IP

EtherNet/IP is an industrial communication protocol developed by Rockwell Automation and managed by ODVA. It is based on CIP and TCP/IP protocol.

EtherCAT

EtherCAT is an open high performance Ethernet-based Fieldbus system. EtherCAT require short data update times with low communication jitter and low hardware costs.

Explosion Proof Sensors

POSITAL explosion proof sensors are designed to operate safely in atmospheres where there are potentially dangerous levels of explosive gases or dust. The IXARC ATEX-certified encoders have been certified in compliance with IECEx and ATEX directives and utilize optical or magnetic technology.

F

Fieldbus Interfaces

Fieldbus networks were developed for vehicle, work cell and factory automation systems. Applications range from conveyors and manufacturing facilities to mobile equipment, medical equipment, wind turbines and solar panels. These networks are based on a bus topology, which simplifies wiring for systems with a significant number of devices. They also support powerful diagnostic tools to help with system setup and trouble-shooting.

Flange Diameter

POSITAL offers different flange diameters 36 mm (ø 1.42") to 78 mm (ø 3.07").

G

Gray Code (SSI)

Encoder Data is sometimes represented in Gray Code. In this code a representation called “Tannenbaum - format” is still quite common. In this representation the first 12 bits represent the multiturn data (revolutions), the second 13 bits represents the singleturn data. The data is centered to the 13 Clk cycle.

I

Incremental Interface

Incremental encoders generate an output signal each time the shaft rotates a certain amount. The number of signals per turn defines the resolution of the device.

IP Rating

The IP (Ingress Protection) rating system is published by the IEC (International Electrotechnical Commission) and classifies the degree of protection that the enclosure provides against solid objects and liquids in order to operate the enclosed electrical equipment.

IP54

Protected against dust and splash water from any direction.

IP65

Dust tight and protected against water jets from any direction.

IP67

Dust tight and protected against temporary immersion up to 1 m.

IP68

Dust tight and protected against long periods of immersion under
pressure.

IP69K

Dust tight and protected against high temperature (steam) and high
pressure water jets from any direction.

Interbus Interface

Interbus is a fieldbus technology developed by Phoenix Contact. Is has been popular in automotive production plants. It can be based on different electrical networks and fiber optics.

Industrial Ethernet Interfaces

While it shares core technology with ‘office’ Ethernet, Industrial Ethernet systems incorporate special hardware and software aimed at providing ‘industrial-strength’ ruggedness and performance. Industrial Ethernet supports larger and more complex networks. It also enables seamless connections between the factory network (Industrial Ethernet) and the enterprise network (office Ethernet) which can simplify the integration of production, inventory control and enterprise management systems.

J

J1939 Interface

SAE J1939 is a Fieldbus standard used for communication by the car and heavy-duty truck industry.

O

Optical Technology

Optical technology is used by POSITAL since 1963 and provides maximum resolution and accuracy by scanning the position of a coded material. The position within 360 degrees is measured using a code disc, infrared LED light and an Opto-ASIC. The number of revolutions is measured with a mechanical gearing. This gearing includes coded gearwheels and LEDs to detect the gearwheels position.

Output Driver

Today most incremental encoders have a Push-Pull (HTL) or RS422 (TTL) output driver, these have replaced most of the older output circuits like Open Collector NPN, Open Collector PNP, Voltage Output.

P

Protection Class

Parallel Interface

Parallel interfaces can provide very high-speed communications over short distances but require bulky cables with individual wires for each bit. All bits of the position output are transferred simultaneously using one line for each bit.

Profibus Interface

Profibus is available on many PLCs and one of the most common fieldbus technologies in factory automation and other areas. It is based on RS485.

Profinet IO Interface

PROFINET is an Industrial Ethernet standard from „PROFIBUS&PROFINET“ International designed for automation.

Programmable Encoders

Programmable encoders have proven to be popular over the past several years since the measurement characteristics of the device (number of pulses per rotation, output level, etc.) can be modified through a software update without requiring any changes to physical components.

Push-Pull (HTL)

Push-Pull (HTL) circuits, also known as Totem Pole, provide a signal level which corresponds to the applied supply voltage. The supply voltage typically ranges from 8 to 30 VDC.

With proper connections you can use the Push Pull interface to replace true open collector circuits by using an external diode connected in a way to limit the direction of the current for.

Powerlink Interface

ETHERNET POWERLINK is a real-time communication system based on Ethernet networks and managed by EPSG.

Pulse Diagram

Pulses per Revolution (PPR)

An incremental rotary encoder outputs a certain amount of Pulses per Revolution. The higher this PPR number, the smaller the angle between each pulse. This PPR number is fixed for ordinary incremental encoders. Programmable incremental encoders can adjust this value to a desired number by a software change.

R

Resolution

Resolution is the smallest angular movement of the shaft that the encoder can detect.

RS422 (TTL)

RS422 (TTL) circuits provide a constant 5 V signal level that is not dependent on the supply voltage. Two supply voltage ranges can be selected: From 4.75 to 5.5 VDC (can be used to replace open collector output drivers) or from 8 to 30 VDC. Using differential signals the output fully complies to the RS422 standard.

The differential outputs have the highest frequency response capability and the best noise immunity. To ensure this the receiver should also be a differential.

Revolutions

Multiturn encoders provide a measurement range of more than 360 degrees by additionally measuring the number of revolutions.

The output signal is based on the number of revolutions as well as on the shaft position within one turn.

S

SSI Interface

SSI is a widely used serial interface with point-to-point connection between PLC/Master and encoder. It is based on the RS422 standard.

SIL Safety Certificate

SIL (Safety Integrity Level) is defined as a relative level of risk-reduction provided by a safety function. In accordance with the requirements of IEC 61508/EN 62061, PL e and Cat.4 according to EN ISO 13849-1, POSITAL product variants OCSxxx and MCSxxx are suitable for the use in safety applications up to SIL 3 and PL e.

Singleturn

Singleturn encoders are providing a measurement range of 360 degrees (one turn). When the shaft of the encoder is turned by more than 360 degrees, output characteristics in subsequent turns will be equal to the first turn.

Square Flange

Square flanges are the most common flanges in the US and are extremely efficient to mount. These square flanges are offered in the common 2" and 2.5" sizes with several shaft options.

Syncro Flange

Synchro flanges were originally designed for use on motors and gearboxes. They are more compact than a clamp flange. Synchro flanges can be installed with clamping discs or directly onto the face with fastening threads.

Serial Interfaces

Serial interfaces use point-to-point wiring systems, but with a digital interface that connects directly to digital PLC’s or microcontrollers. They offer good speed, high resolution, flexible cabling and reliable communication over distances up to a few hundred meters.

Solid Shaft

POSITAL provides a wide range of solid shaft solutions including clamp, synchro and square flanges. Various metric and inch diameters as well as flats and keys are also available for solid shafts.

Shaft Diameter

POSITAL offers different shaft diameters from 6 mm (ø 0.24") to 15 mm (ø 0.59").

T

Through Hollow Shaft

Through Hollow options are also available through POSITAL's portfolio. With this kind of design, the shaft completely passes through the body of the encoder.

TTL Incremental Interface

Z

Z Signal

Some incremental encoders output a “Z” signal. Once every rotation, this Z signal is rising for typically 90°, on the exact same position. This can be used as an accurate reference point.