Industrial Telediagnostics: Definition and Challenges
Industrial remote diagnostics (or remote diagnostics) refers to the set of practices and tools that enable a technician or engineer to diagnose industrial equipment, identify a malfunction or deviation, and resolve the issue remotely—without being physically present on site.
Unlike simple monitoring (reading data), remote diagnostics is an active process: the technician analyzes, queries the equipment, reviews logs, modifies settings, and can initiate corrective actions. That is the difference between observing and taking action.
The challenges are considerable in today’s industrial landscape:
- Shortage of specialized technicians: Experts in automation and industrial maintenance are scarce and often concentrated in a few locations
- Increasing number of sites: a service provider may oversee dozens of remote sites with the same staff
- Availability requirements: production downtime is costly—every hour counts
- Sustainability: reducing travel lowers the carbon footprint
What Industrial Remote Diagnostics Enables
Troubleshooting
The vast majority of industrial malfunctions result in error messages in PLCs, drives, and HMIs. This information can be accessed remotely:
- PLC diagnostic buffer: error history with timestamps, value at the time of the fault
- Drive fault log: faults, current at trip, temperature, operating time
- HMI alarms: history of alarms and operator acknowledgments
- System logs: I/O status, sensor values, communication status
Changing Settings
Once the cause has been identified, the remote technician can often resolve the issue without having to visit the site:
- Drive parameters: adjustment of protection thresholds and acceleration ramps
- PLC recipes: modification of process parameters (temperatures, pressures, cycle times)
- HMI configuration: adding indicator lights, modifying alarm thresholds
- Network settings: correcting IP addresses and Modbus baud rates
Remote Resetting
Remotely resetting equipment that has tripped is the most delicate but also the most useful action: production can resume immediately after the cause has been verified.
Architecture of an Industrial Remote Diagnostics Solution
Field Equipment, 4G VPN Network, Monitoring Center
───────────────────── ───────────── ─────────────────────
PLC ─────────┐ TIA Portal Engineer
Variateur ────────────┤ ┌──────────────┐ Technicien VNC
HMI ────────────┤── 4G Router ─┤ VPN Tunnel ├── Internet ───── SCADA / Monitoring
Energy Meters ────┤ └──────────────┘ CMMS / Ticketing
Capteurs ─────────────┘
The connection is always initiated from the site (outbound VPN): no ports are open to the Internet on the industrial site side. This is a fundamental principle of OT security.
Traceability and Documentation of Interventions
A mature industrial remote diagnostics system includes full traceability:
Automatic logs:
- Date and time of VPN connection and disconnection
- Technician’s identity (name-based authentication)
- Session duration
- Source IP address
Service Report:
- Reported symptom
- Remote diagnosis
- Actions taken (parameters changed, before/after values)
- Result (problem resolved / on-site service required)
- Time spent
This traceability is invaluable for ISO 9001 quality audits, ISO 50001 (energy) certifications, and NIS2 compliance.
NIS2 Compliance and Cybersecurity for OT Remote Access
The European NIS2 Directive imposes strict cybersecurity requirements on the information systems and operational technology (OT) systems of critical and important entities. For remote maintenance access:
| NIS2 Requirement | Technical Implementation |
|---|---|
| Strong Authentication | MFA (2FA) for VPN, role-based access |
| Communication Encryption | IPsec or TLS 1.3 VPN |
| Logging | VPN logs + monitoring logs, 12-month retention |
| Third-Party Access Management | Temporary accounts with automatic expiration |
| Incident Notification | CSIRT procedure within 24 hours |
| Security Testing | Annual audit of remote access |
A properly configured and documented industrial VPN is the backbone of NIS2 compliance for remote access.
ROI of Telediagnostics: Calculation and Feedback from the Field
The return on investment for an industrial remote diagnostics solution is generally very quick. Here is an example calculation:
Assumptions:
- 2 remote industrial sites (200 km apart)
- Average of 3 maintenance calls per month
- Average cost of a service call: 800 € (travel + technician time)
- Remote resolution rate: 65% of service calls
Monthly calculation:
- Total service calls: 3 × 2 locations = 6 per month
- Service calls avoided: 6 × 65% = 3.9 trips avoided
- Monthly savings: 3.9 × €800 = €3,120/month
Payback Period:
- Solution cost (routers + subscriptions + deployment): ~€4,000
- Payback period: less than 2 months
In fact, the benefits are even broader: shorter response times (immediate response vs. a 2- to 4-hour travel time), improved customer satisfaction, and technicians who are less likely to have to travel at night.