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# Delta PLC — Advanced Ethernet PLC Programming
- URL: https://inferconautomation.com/blog/delta-plc-ethernet-modbus-tcp/
- Published: 2026-05-05T00:30:00.000Z
- Updated: 2026-05-05T00:30:00.000Z
- Description: Configure Modbus TCP/IP communication, networking, and remote I/O on the Delta PLC.
- Author: Inferconautomation
- Tags: Delta PLC, Delta, PLC, Modbus TCP, Ethernet, #Import 2026-10-29 12:58

The **Delta PLC** takes Delta's compact PLC line into the networked era — built-in 10/100 Mbps Ethernet, Modbus TCP server/client, and dual RS-485 ports make it ideal for connected machines.

## 1\. PLC at a Glance

- 8 DI + 4 DO (transistor outputs)
- Built-in Ethernet (RJ-45)
- 2× RS-485 ports (independent baud rates)
- Supports Modbus TCP (server & client) and Modbus RTU

## 2\. Configuring Ethernet

In **PLC software**, set the IP address, subnet mask, and gateway in HW Config. Default IP is usually 192.168.1.5 — change it to match your factory network. Save and download to PLC.

## 3\. Modbus TCP Server (Slave) Mode

By default, the PLC acts as a Modbus TCP *server*. Any SCADA, HMI, or Python script can read/write the D registers and M coils via TCP port 502.

> **💡 Quick Test**From a laptop on the same subnet, use `modpoll` or **QModMaster** to read register D0 — confirms the connection before integrating SCADA.

## 4\. Modbus TCP Client (Master) Mode

The PLC can also poll remote devices. Use the **MODRW** instruction in PLC software to issue Read Holding Registers (FC03) or Write Single Register (FC06) to remote slaves.

## 5\. Real-World Use Case

One PLC controls a small filling line, while a second PLC handles capping. Both publish run-status registers via Modbus TCP. A single SCADA software station polls both PLCs — no hardware gateway needed.