PLC to MQTT Gateway

The problem

Headquarters wants production data from every plant in the cloud, but opening PLC networks to the internet is not acceptable to the plant’s IT and safety teams.

Solution overview

MILESGO gateways collect data from PLCs, production counters and machine state signals, electricity meters over S7 / Modbus TCP / EtherNet/IP, and deliver it to a cloud platform (MQTT), a historian / database (MySQL, SQL Server, InfluxDB) as MQTT. Field equipment keeps its own protocol and control logic; integration is done by configuration and point mapping, not custom code.

Typical scope

PLCs
production counters and machine state signals
electricity meters

Protocol path

S7 / Modbus TCP / EtherNet/IP → MQTT

Implementation checklist for the project manager

Keep OT networks segregated and use VPN for remote access instead of opening ports to the internet.
Do not modify validated PLC programs; read existing data areas or add gateway-side mapping instead.
Confirm local storage so data survives network outages, and define the retention period.
Check 4G signal and the SIM data plan at every site before committing to cellular backhaul.
Fix a site / asset naming convention before the first site so data from all sites can be compared.
Standardise one configuration template per equipment type so further sites are copied, not rebuilt.

Project deliverables

Signed point table and protocol mapping
Gateway configuration files and backups
IP address plan and network drawing
FAT and SAT test records
As-built documentation and operator training

System architecture

Field layer: PLCs, production counters and machine state signals, electricity meters, connected over S7 / Modbus TCP / EtherNet/IP. Edge and integration layer: MILESGO protocol gateways and edge controllers, mounted on DIN rail in existing panels, polling each device, time-stamping values and buffering them locally. Upper layer: a cloud platform (MQTT), a historian / database (MySQL, SQL Server, InfluxDB), which receives the data as MQTT. Remote access for maintenance runs over VPN rather than open internet ports.

System composition

Field devices: PLCs, production counters and machine state signals, electricity meters
Edge / integration: MILESGO protocol gateways and edge controllers
Upper systems: a cloud platform (MQTT), a historian / database (MySQL, SQL Server, InfluxDB) (MQTT)
Tools and commissioning: Web-based configuration, point table import/export (Excel), off-site simulation and on-site diagnostic tools

Software and AI capabilities

Anomaly detection on trend dataRoadmap
Predictive maintenance indicators from equipment trendsRoadmap

Delivery steps

1
Site survey and point list
Inventory devices, protocols, register maps, panel space, power and network paths.
2
Design and point table sign-off
Map every point to the target protocol and system; agree it with the client and the upper-system contractor.
3
Configuration and FAT
Build the gateway configuration off site, simulate it and test against the signed point table.
4
Installation and wiring
Mount gateways on DIN rail, wire RS-485 / I/O / Ethernet, apply the IP plan.
5
SAT and alarm tests
Verify values against local readings, test every alarm and command end to end.
6
Handover and support
Hand over configuration backups, point table and as-built documents; train operators.

Customer value

Data ready for cloud platforms and analytics
Data kept locally during network outages
Monitoring added without changing existing control programs
Configuration templates reused across sites

Tell us about your project

Send the protocols, point count and target system. A sales and engineering pair reviews every submission.

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