Industrial Technical
Industrial Network Communications Fundamentals — Modbus, RS-485, and Ethernet
Configure and troubleshoot Modbus, RS-485, Ethernet, IPv4, switching, diagnostics, OT security, backup, and rollback in an isolated virtual network.
Who this is for
Intended audience
Controls, instrumentation, maintenance, and industrial IT/OT personnel who configure or troubleshoot isolated training networks.
Relevant industries: Manufacturing, Automation, Petrochemical, Utilities
Learning outcomes
What learners will work toward
- Explain the industrial network stack from physical media through application protocol.
- Distinguish serial, Ethernet and IP communication concepts.
- Explain balanced differential signaling and RS-485 two-wire/four-wire topologies.
- Recognize polarity, common reference, termination, biasing, shielding, grounding and noise issues.
- Select and document baud rate, framing, addressing and timing parameters in course scenarios.
- Interpret Modbus RTU frames, function codes, data models, register addressing and exception responses.
- Configure and troubleshoot virtual Modbus RTU client/server exchanges.
- Explain Modbus TCP encapsulation, MBAP header concepts, TCP port 502 and unit-identifier use.
- Configure IPv4 addresses, masks, gateways and simple subnets.
- Explain MAC addressing, ARP, switching, collision/broadcast domains, VLAN awareness and link negotiation.
- Recognize managed-switch, gateway, router/firewall and media-converter roles.
- Read industrial network drawings, asset inventories, port maps, IP plans and register maps.
- Use packet captures and serial logs to distinguish physical, data-link, network, transport and application faults.
- Troubleshoot addressing, timeout, duplicate-address, framing, termination, bias, noise, cabling and gateway faults.
- Establish baseline, backup, change, validation and rollback records.
- Apply OT security fundamentals from NIST SP 800-82 Rev. 3 and current backup guidance.
- Recognize unauthorized discovery, scans, remote access, insecure defaults and uncontrolled changes.
- Complete an integrated virtual-network capstone.
Course outline
17 modules
Orientation, Network Ownership, and Safe Lab Boundary
Establish network-owner authorization, maintenance windows, backups, rollback and incident escalation. Discovery scans, packet injection, address changes or configuration downloads can disrupt real processes. All course activity occurs in an isolated simulator with no route to production.
Industrial Communication Architecture and Layered Troubleshooting
Introduce physical media, data link, network, transport and application functions using an industrial stack. Compare point-to-point, multidrop, switched Ethernet and routed architectures. Troubleshooting starts at power/media and proceeds upward rather than changing application settings randomly.
Serial Communication Fundamentals
Teach asynchronous serial data, bits, baud rate, start/stop, parity, data bits, framing, duplex and timing. Explain why every participant must match the communication parameters and why baud rate is not identical to useful application throughput.
RS-485 Electrical Fundamentals
Cover balanced differential signaling, A/B or +/- naming ambiguity, common reference, receiver threshold, common-mode range awareness, two-wire and four-wire use, driver enable, multidrop and stub effects. The actual equipment manual controls terminal naming.
Termination, Biasing, Shielding, Grounding, and Noise
Termination belongs at the ends of the main trunk and should match cable impedance under the applicable design. Biasing/fail-safe networks establish a known idle state but must be coordinated with device internals. Teach shield and grounding strategies as manufacturer/system-specific, avoiding a universal one-end rule. Cover common-mode, induced noise, ground loops, cable segregation, surge and isolation.
Modbus Data Model and Addressing
Explain coils, discrete inputs, input registers and holding registers. Separate protocol data address from human reference notation such as 0xxxx/1xxxx/3xxxx/4xxxx. Device documentation may use zero-based or one-based display conventions; the register map is authoritative.
Modbus RTU Frames, Function Codes, and Exceptions
Teach slave/server address, function code, data, CRC and silent-interval framing. Include common read/write function codes, quantity limits at a foundational level, broadcast address concept and exception responses. Exact specification values are sourced from the current Modbus specifications.
Modbus RTU Timing, Polling, and Troubleshooting
Cover inter-character/inter-frame timing, timeout, retry, scan/poll rate, bus loading, duplicate address, response delay, device turnaround and stale data. Troubleshoot no response, CRC error, exception, intermittent response and wrong data.
Ethernet Physical and Data-Link Fundamentals
Cover copper/fiber awareness, link speed/duplex, auto-negotiation, MAC address, frames, unicast/broadcast/ multicast, switching, port status and loop awareness. Modern switched Ethernet differs from legacy shared hubs/collision domains. Managed features are introduced without vendor-specific commands.
IPv4 Addressing, Subnetting, ARP, and Gateways
Teach binary/decimal masks, network/host portions, usable addresses, default gateway, private address space, ARP, duplicate IP and routing boundary. Use industrial examples with small subnets. Learners calculate and document address plans without connecting to a live system.
Managed Switches, VLAN Awareness, Redundancy, and Time
Introduce port descriptions, speed/duplex, VLAN access/trunk concepts, port mirroring, diagnostics, redundancy protocols at awareness level, quality-of-service concepts and time synchronization. Uncontrolled redundancy or VLAN changes can create loops or loss of control communication.
Modbus TCP and RTU/TCP Gateways
Explain TCP port 502, MBAP transaction/protocol/length/unit fields, PDU relationship and multiple outstanding transactions conceptually. Gateways map Ethernet clients to serial server addresses and add timeout, unit-ID, framing and queue considerations. A ping success does not prove the Modbus application works.
Network Drawings, Asset Inventories, Port Maps, and Baselines
Create physical/logical diagrams, asset inventory, device owner, model/firmware, MAC/IP, switch port, protocol, serial parameters, register map, backups and approved communication paths. Baselines support troubleshooting and recovery. Sensitive network data requires access control.
Packet Capture and Serial-Log Analysis
Use prebuilt packet captures and serial logs. Identify ARP, ICMP, TCP handshakes, resets/retransmissions, Modbus requests/responses and exception codes. Explain the limits of passive capture and the authorization required for active tests. No offensive exploitation content is included.
Systematic Network Troubleshooting
Confirm scope and authorization; preserve evidence; verify power/media/link; verify serial parameters or IP/MAC/VLAN path; verify transport; verify protocol request/response; compare register map and application state; document findings; implement approved change; validate and roll back if needed. Faults include reversed pair, missing termination, duplicate address/IP, wrong parity, wrong mask, closed port, bad unit ID, timeout, gateway mapping, switch VLAN and stale data.
OT Security, Remote Access, Backups, and Change Control
Use NIST SP 800-82 Rev. 3 for OT security principles and NIST SP 1339 for current backup quick-start guidance. Cover inventory, segmentation, least privilege, secure remote access, change authorization, logging, removable media awareness, default credentials, vulnerability/patch governance, backups, offline/immutable copies, restore testing and incident escalation. The course does not teach exploitation.
Virtual-Network Capstone
The capstone includes a virtual PLC, HMI, remote I/O, serial devices, managed switch and RTU/TCP gateway. The learner interprets the drawing and asset/register list; configures RS-485 and Modbus RTU; configures an IPv4 subnet and switch ports; establishes Modbus TCP/gateway communication; diagnoses injected faults; analyzes packet captures; backs up configurations; documents baseline/change/rollback; and identifies unsafe or unauthorized actions.
Assessment and completion
Requirements stay explicit.
Assessment plan: 90-question protected staging QA assessment; 80% plus the critical-item rule. The 90-item draft seed bank must expand to 270 independently approved items before paid release.
Questions
Frequently asked
Is this an official OSHA or third-party certification?
No. IM Academi will identify the course provider and the exact completion outcome. It will not imply OSHA authorization, regulatory qualification, or another organization's certification unless the applicable authorization has been obtained and documented.
Does my employer still need to provide site-specific training?
Often, yes. Site hazards, procedures, equipment, emergency plans, supervision, and role authorization remain employer responsibilities. This page states course-specific boundaries but cannot replace an employer's hazard assessment.
What happens if a practical component is required?
The knowledge portion and practical evaluation are tracked separately. Final completion depends on the published course rules and a documented evaluation by an approved evaluator.
Need this course for a team?
Discuss assignments, delivery, practical coordination, and reporting needs.