Fieldbus encoder - Revolutions translated into speed and position
An encoder is a measuring device that translates shaft rotation into an analogue or digital signal. The signal is transmitted via a communication protocol and translated into speed, distance or position. Encoders can be divided into incremental and absolute encoders. The number of revolutions (single-turn or multiturn), resolution, protection class, housing type, type of cable and cable connection, connectors and shaft properties are important factors when choosing a fieldbus encoder.
Encoders with fieldbus interface
A fieldbus or fieldbus is an industrial, digital bus for controlling machines and processes. There are big differences between fieldbus standards. Different fieldbuses are not always compatible with each other and often emphasise different functionalities. Applications range from conveyor belts and manufacturing facilities to mobile equipment, medical equipment, wind turbines and solar panels. Examples of fieldbus networks are: Profibus, CANopen and DeviceNet.
PROFIBUS and CANopen fieldbus
Profibus is the first international, open and manufacturer-independent fieldbus for building, production and process automation (in accordance with EN 50170). Profibus has three different versions: Profibus PA, Profibus DP and Profibus FMS. Profibus PA is mainly intended for process automation and can be used in explosion-proof environments. Profibus DP (decentralised periphery) is intended for fast data exchange in the field of building and factory automation for digital controllers, among others. Profibus FMS (Field Message Specification) is suitable for data exchange with higher layers and object-oriented communication in the cell and field area.
CANopen fieldbus interface
CAN stands for Controller Area Network and was developed for automotive and factory automation applications. The CANopen fieldbus is also used for industrial applications. CAN is a multi-masterable system, which means that all users can access the bus at any time, as long as the fieldbus is free. If the fieldbus is busy, the user with the highest priority is given priority. DeviceNet is also a CAN protocol, but uses Communications and Information Protocol (CIP).
Encoder for speed and position measurement
Scancon's eCODE series fieldbus encoders use a high-precision interpolating optical system that provides high-resolution measurement. All data from the interpolating system is processed by the microprocessor. With an update rate of 10 milliseconds, the data are processed so that the information is always up-to-date. The values are available through the Profibus fieldbus interface.
Features ecode encoder SCA94DD:
- High resolution
- Profibus fieldbus interface
- High update rate: 10 ms
- Robust design with aluminium housing
- Up to 50 rpm
- Protection rating: IP67
- Temperature: -40°C to +85°C
Dual output fieldbus encoder for ATEX zone 1
The EXAG dual output fieldbus encoder is intended for use in the oil and gas industry, ATEX Zone 1 with the possibility of feedback to different devices. The EXAG dual output fieldbus encoder has both incremental and absolute output and is compatible with one of the fieldbuses: Profibus, DeviceNet or CANopen.
The dual output encoder has a resolution of up to 30 bits multi-turn and an incremental resolution of up to 8192 pulses per revolution. Read more about EXAG dual output encoder.
EXAG dual output encoder features:
- 30-bit resolution (absolute)
- Fieldbus interface: Profibus simultaneously with incremental output
- Up to 8192 pulses per revolution (incremental)
- Temperature: -40°C to +70°C
- Protection rating: IP64 to IP68
Profibus data cable for fieldbus encoders
Fieldbus encoders transport signals via Profibus and DeviceNet/CANopen data cables. Profibus cables must meet bus-specific requirements of the Profibus/Profinet organisation (PNO).
Cables and connectors from ESCHA
ESCHA's cables comply with this and are available in 5-pole (B-coded), M12, T-splitters and Y-splitters, connectors, chassis parts or recaptacles with sealing up to IP68 and 360° shielding and comply with IEC 61076-2-101. The profibus cables can withstand temperatures from -30 °C and +90 °C.
CANopen and DeviceNet data cables for fieldbus encoder
For CANopen cables and DeviceNet cables, user organisation ODVA prescribes a number of requirements:
- 5-pin M12 connectors
- PUR cable
- halogen-free cables chassis parts or receptacles
- shielded cables
- twisted cables for signals and supply voltages with stripped cable ends
The CANopen cables and DeviceNet cables have UL certification and can handle resistances up to 120Ω. The cables are available in 5-pole (B-coded), M12, T-splitters and connectors, chassis sections or receptacles with sealing up to IP68. The latter over-mold meets the requirements for protection class IP69K. The CANopen/DeviceNet cables withstand temperatures from -30 °C and +90 °C and comply with standard IEC 61076-2-101.