Fieldbus and Protocols: CANopen, Profibus and Industrial Ethernet
Choosing a fieldbus is never about which protocol is better; it is about what the existing master can open, whether a module can be added, and whose backbone is already in the plant. These articles start from the master side, then cover the CANopen object dictionary and frames, Profibus GSD configuration, and the real-time limits of the two Ethernet families.
01Choosing the protocol
- Selecting a Fieldbus: Start From the Master Controller Type
Which bus? Match the machine master—CANopen, Profibus, EtherCAT, PROFINET—then weigh timing. This magnetostrictive displacement sensor tables them.
- Choosing a Displacement Sensor Fieldbus: Which Bus My PLC Supports
Which fieldbus fits your sensor? Look in the PLC list: CPU port, addable modules, existing backbone. This locks PN, DP and CAN before a gateway.
- Magnetostrictive output signals compared: eight interfaces and their trade-offs
Eight outputs. A magnetostrictive displacement sensor differs by cores, noise, diagnostics: 4-20 mA cries open wire; 0-10 V reads break as zero.
- Magnetostrictive Displacement Sensor on Industrial Ethernet: PROFINET vs EtherCAT
Pick 199PROFINET for a new S7-1200/1500 line needing IRT; pick 197/198 EtherCAT where clocks align axes. Confirm which master your PLC carries.
02CANopen
- CANopen Displacement Sensor: Object Dictionary and PDO/SDO Split
CANopen keeps values in the object dictionary. A magnetostrictive displacement sensor follows DSP 406: position at 0x6000 over TPDO, params over SDO.
- Magnetostrictive Displacement Sensor Series 194: CANopen DSP406 in Practice
One twisted pair links several axes of this CANopen displacement sensor. Series 194 follows DSP406, uses PDO, ends at 120 ohm; stop polling over SDO.
- Germanjet CANopen Sensor Master: Command Bytes and States
A PLC hides the protocol behind a node number and an EDS import; a custom board hides nothing. Using the object dictionary of the Germanjet 194 series, this covers the command bytes, state machine and byte order a microcontroller master needs, and marks which indices are brand-specific.
- CANopen Displacement Sensor: EMCY, Node Start, PDO and SYNC Communication Examples
A CANopen displacement sensor messaging guide: on power-up the sensor sends EMCY (0xFF, default node 0x7F), the controller sends a node-start frame (0x000, 01 00) and the sensor replies with PDO data. A single magnet uses PDO1 at 0x1FF; dual magnets add PDO2 at 0x2FF. Every frame is 7 bytes: 4 bytes of position, 2 bytes of speed and 1 reserved byte, LSB first. Synchronous mode is driven by SYNC; asynchronous mode transmits on its own timer.
- CANopen Displacement Sensor: Changing Baud Rate, Node ID and Event Timer over SDO
Change a CANopen displacement sensor's baud rate, node ID and CAN event timer over SDO, then save to EEPROM: baud rate is object 0x2010, node ID is 0x300B with the new value in byte 5, event timer is 0x1800 sub-index 0x05, and 0x1010 saves the lot. SDO requests use cob-id 0x600 + node ID. Not sure of the current address? Read the EMCY cob-id and subtract 0x80.
- CANopen Multi-Magnet Reading: 8-Byte Frame Limits and PDO Mapping
One waveguide, several magnets, an 8-byte frame. A TPDO holds just two INT32 positions, so three magnets need SYNC batches; minimum spacing is 76 mm.
- CANopen Displacement Sensor: Node Address and Baud-Rate Faults
A CANopen magnetostrictive displacement sensor that will not join the bus fails on two things: node IDs 1-127, and baud rate set by cable length.
03Profibus and PROFINET
- Magnetostrictive Displacement Sensor Series 195: PROFIBUS GSD and Diagnostics
GSD must match firmware or the slave shows up but will not configure. This Profibus displacement sensor guide covers address clashes, baud, end plugs.
- Profibus Displacement Sensor: GSD Import and Slave Configuration
Profibus setup: three clicks, then traps. Import the GSD, hang the slave, set its address, pick the data module - a wrong module shifts every byte.
- Profibus Sensor Diagnostics: Terminating Resistor and Segment Tests
Most Profibus faults are on the wires. Its 390/220/390 DB9 network reads 110 Ω power-off with both ends ON: match is 220 Ω, held plug stays powered.
- Magnetostrictive Displacement Sensor Series 199: PROFINET RT, IRT and Device Names
PROFINET uses device name, not IP. RT fits general data, IRT only reserved-slot sync. This PROFINET displacement sensor flags topo errors on re-wire.
04EtherCAT and others
- Magnetostrictive Displacement Sensor Series 197: EtherCAT State Machine and DC Clocks
The frame flies past; slaves read their bit. With DC synchronization, this EtherCAT displacement sensor suits multi-cylinder lifting; bus speed lags.
- EtherCAT Displacement Sensor: ESI, State Machine and Distributed Clocks
An EtherCAT magnetostrictive displacement sensor needs ESI plus state machine. Match XML to firmware, walk INIT→OP, keep IN/OUT order or scan scrubs.
- EtherCAT Real-Time: Distributed Clocks Align Instant, Not Measurement Speed
EtherCAT cannot break physics. DC aligns samples but cannot cut wave travel, so a longer-range magnetostrictive displacement sensor still runs slower.
- A Modbus Displacement Sensor: Two Registers to a 32-Bit Position
Reading position over Modbus means merging two 16-bit words into a 32-bit value, then scaling. Watch byte order, signed versus unsigned and poll lag.
- An IO-Link Displacement Sensor: The Last Hundred Metres to the Cloud
IO-Link magnetostrictive sensor frees the last hundred metres: one device per port, then a master sends value and events to PROFINET or EtherCAT.
05Networking and integration
- Magnetostrictive Sensor Fieldbus: CANopen and EtherCAT Integration
Stuck on CANopen Node-ID and PDO mapping? This fieldbus guide for a magnetostrictive displacement sensor covers Node-ID, PDO not SDO and 120-ohm ends.
- Magnetostrictive Displacement Sensor Fieldbuses: CANopen vs Profibus for Position Feedback
CANopen 194 and Profibus 195 look serial but differ in layer: CANopen is a 120-ohm pair for mobile machines; Profibus keeps an S7-300/400 DP network.
- Connecting a Digital CANbus Integration Module to a PLC: Seven Configuration Steps
Seven steps to connect a digital CANbus integration module to a PLC: keep the PLC master address away from 7F (the module default), set both sides to 500 kbps, install the EDS file and add the module, set the module address to 7F, map and download the PDO configuration, wire terminals 1 = CAN-H, 2 = CAN-L, 19 = +24 V dc, 20 = 0 V dc, then power up and verify. PLC settings differ slightly between manufacturers.
- Fieldbus Displacement Sensor Power-Loss Hold: Position Versus Parameters
After a power cut, a fieldbus sensor still knows position from the magnet, no homing. Parameters survive only if stored; CANopen needs a write.
- How to Network Displacement Sensors Under Industry 4.0
On the line a networked magnetostrictive displacement sensor is no raw value; it carries address and diagnostics. Match the PLC port before ordering.
- How Many Axes Can One Bus Carry? Time Budget for a Magnetostrictive Displacement Sensor
Axes per bus? This magnetostrictive displacement sensor obeys a time budget: update within cycle within loop. CANopen, EtherCAT, PROFINET ranked.
06Related products
- Series 19 CANopen bus magnetostrictive displacement sensorSeries overview
- Series 19 Profibus bus magnetostrictive displacement sensorSeries overview
- Series 19 EtherCAT bus magnetostrictive displacement sensorSeries overview
- Series 19 Profinet bus magnetostrictive displacement sensorSeries overview
- Digital/CANbus Integration ModuleSeries overview
- Digital/EtherCAT Integration ModuleSeries overview