Industrial Interfaces: RS-485, Modbus, CAN and Isolation

10 Lektionen in dieser Stufe

1. Differential Signalling and Why Long Cables Need It
   Explain common-mode noise rejection and the limits of single-ended logic. · Lab: Send UART data over 10 m of cable single-ended and then differentially and compare errors near a noise source.
2. RS-485 Transceivers, Termination and Biasing
   Wire a correct multi-drop bus with termination and fail-safe bias resistors. · Lab: Build a three-node bus and observe reflections with and without termination.
3. Half-Duplex Direction Control and Bus Timing
   Switch the driver on and off at the right moments and respect turnaround gaps. · Lab: Implement driver-enable control and verify timing on the logic analyzer.
4. Modbus RTU Frames, Function Codes and CRC
   Read and construct requests and responses and compute the CRC-16. · Lab: Decode captured frames by hand and verify their checksum.
5. Building a Modbus RTU Server Device
   Expose sensor values and settings as input and holding registers. · Lab: Turn a sensor board into a server and read it from PC software through a USB adapter.
6. Polling Field Devices as a Modbus Client
   Query several servers in turn with timeouts, retries and error counters. · Lab: Poll two servers and display values and communication statistics.
7. CAN Bus Physical Layer, Arbitration and Error Handling
   Explain dominant and recessive bits, priority by identifier and automatic fault confinement. · Lab: Wire a two-node bus with termination and observe arbitration when both send at once.
8. Sending and Filtering CAN Frames with an MCP2515 Module
   Configure bit rate, masks and filters and exchange frames between different boards. · Lab: Send sensor frames from one node and filter them on another, then add a 32-bit board with built-in CAN controller.
9. Designing a CAN Message Dictionary
   Define identifiers, payload layouts, scaling and update rates for a system. · Lab: Write a message table for a small machine and implement encode and decode functions.
10. Galvanic Isolation and 24 V Industrial Inputs and Outputs
    Separate field wiring from logic with optocouplers, digital isolators and isolated supplies. · Lab: Build an isolated 24 V input and a relay output and verify there is no continuity between the two sides.

Abschlussprojekt

A multi-drop RS-485 Modbus sensor network with two server devices and a client, bridged to a CAN node, with isolated 24 V inputs and outputs.

Teile für diese Stufe

• 2 × UNO-compatible board
• 1 × ESP32 development board
• 1 × STM32 development board with Cortex-M3 or M4
• 4 × USB cable matching each board
• 3 × RS-485 transceiver module
• 1 × USB-to-RS-485 adapter
• 2 × MCP2515 CAN module with transceiver
• 1 × CAN transceiver module 3.3 V
• 1 × Twisted-pair cable 10 m
• 4 × Resistor 120 ohm
• 2 × Resistor 680 ohm
• 1 × Optocoupler module 4 channel
• 1 × Isolated DC-DC converter module
• 1 × Digital isolator module
• 1 × Power supply 24 V 1 A
• 2 × Buck converter module adjustable
• 8 × Screw terminal block 2-pin
• 1 × USB logic analyzer 8 channel
• 1 × Digital multimeter
• 2 × BME280 pressure, humidity and temperature module
• 1 × Relay module 5 V single channel

In jeder Lektion legst du die passenden Teile direkt in den Warenkorb. Arduino-kompatibel →