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Edge Gateway

Any device to Modbus Server (slave)

The gateway as a Modbus slave: tags from any protocol, served as registers and coils to equipment that only speaks Modbus.

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The data flow

ANY SOURCE, SERVED AS MODBUSAny deviceS7 · EtherNet/IP · a meter …Edge Gatewaythe runtime on your devicepolls · decodes · scalesplaces tags in four register spacesModbus masterSCADA · PLC · panelFC01–04 over TCP, RTU or ASCIInumbers as holding / input registersbooleans as coils / discrete inputs

A server-style output. Numbers are served in the type and byte order you choose, booleans as bits. Write function codes are refused: the gateway stays read-only towards the plant. A tag whose quality is not good is answered with exception 04 (or the last good value, or zero, if a master cannot cope with exceptions). The register map is written next to the runtime's data so an integrator can read it.

In the editor

Edge LogicPump house✓ Saved · v3DeployFilter nodes…PLC & INDUSTRIALModbusSiemens S7Allen-Bradley (CIP)…TRANSFORMSScaleDeadbandExpression…LOGIC & ROUTINGCondition / RouteJoinInject / TriggerOUTPUTMQTT outHTTP outSQL out…GATEWAYModbus converterLine PLCSiemens S7 · 192.168.1.30every 500 ms · 8 tagsOld SCADAModbus Server outTCP · 0.0.0.0:502 · unit 1Old SCADASERVE OVERModbus TCPLISTEN ADDRESS0.0.0.0:502UNIT ID1REGISTER MAPSpeed → 40101, Run → 00001NUMBERS SERVED ASfloat32 · ABCD
An S7 PLC read by the gateway and served to a SCADA that only speaks Modbus.

The node's register map fixes where each tag is served (holding:100, input:200, coil:5, or the reference form 40101); a tag not in the map is placed after First address for unlisted tags, numbers in holding registers and booleans in coils. Serve over is TCP with a listen address, or RTU or ASCII with a serial port and its line settings.

Test it with the Modbus Simulator

You do not need the PLC to try this flow. The Modbus Simulator answers as a Modbus slave on your own PC, with registers that move, so the whole path from polling to the output can be watched before any hardware is involved.

  1. Start the Simulator and add a slave: Modbus TCP, bind host set to this PC's LAN address (the prefilled one), port 1502, unit ID 1. Add a few holding registers, say 40001–40010 as FLOAT32 or INT16 in random mode so the values change, and press Start.
  2. In the editor, set the source node's host to that address, port 1502, unit ID 1, and the same addresses and data types. Poll interval 1s is fine.
  3. Deploy the design to a device on the same network, or to this very PC: the Edge Gateway Console installs on a laptop as readily as on an edge computer, and the gateway polls the Simulator over the LAN.
  4. The Simulator's request log shows the gateway's reads arriving: function code 03, the start address and quantity, once per poll interval. Neighbouring registers arrive as one read.
  5. The gateway is now a slave itself: read it with the Modbus Client at the listen address, unit ID 1, the mapped registers. The Client shows the Simulator's values arriving through the gateway, and exception 04 when you stop the Simulator.
THE TEST BENCHModbus Simulatora slave on your PC · port 1502registers in random moderequest log shows each readEdge Gatewaythe runtime on your devicepolls every secondthe live view shows valuesThe outputon the same PC or elsewhere

Registers in fixed mode make a deadband or a condition easy to exercise: change a value by hand and watch what is, and is not, published. A register set to a value the Simulator refuses (uncheck Fill unmapped and read an address that is not there) shows what a BAD quality looks like at the output. The Simulator's own page has the rest.

From design to device

THE SAME FOUR STEPS FOR EVERY FLOWValidateon the design pageInstallthe console on the deviceDevice codeentered on the design pageBundlegiven to the console
  1. Validate. On the design page, Run validation. The editor's rules, the tag document and the runtime binary itself check the design; every issue names its node. Details: Validating a design.
  2. Install. From the Devices panel download the installer for the device's platform (Windows x64, Linux x64 or Linux ARM64). Windows: extract and run Edge-Gateway-Console.exe from an administrator terminal. Linux (Debian, Ubuntu, Raspberry Pi OS): sudo dpkg -i the .deb, then sudo edge-gateway-console. It shows the device code. Details: Installing on the device.
  3. Device code. Enter it in the Devices panel, choose a trial or one of your purchased licences, and press Download activation bundle: one small zip with the design and a licence bound to that machine, sealed so only that machine can open it. Details: Downloading.
  4. Bundle. Give the zip to the console (drag it onto the program, pass its path, or put it beside the program and run it again; a USB stick is fine for a device without internet). It opens the bundle with its own code, installs the runtime as a service and starts it. The device never contacts the site. Details: Activation and the licence.

The console then opens the gateway's web view in a browser (on a device without a desktop it prints the address instead) and stays attached with the live view: devices up or down, values as they change, what was published, and the log.

  • The live view shows the Modbus server as listening and counts the requests it answered.
  • The register map the runtime assigned is written as <destination>-modbus-map.json in the data directory: every tag, its register, type and byte order, for the integrator on the other side.

Ctrl-C leaves the gateway running as a service. Run edge-gateway-console again at any time: it shows the service, the licence, every device and destination with what to check, the web view, and the live log. Running covers the data directory, secrets and the diagnostics.

Any device to Modbus Server (slave) · Edge Gateway documentation | Modbus Logic