PLINK Head & Expansion Modules (PM Series)
A flexible I/O expansion solution for Smart series and Ethernet/RS485 distributed IO. Choose the right PLINK header, then add PM expansion modules for Digital I/O, Analog I/O, and Temperature.
- Short-distance expansion near devices
- Long-distance distributed remote IO
- Smart / S7-1200 / S7-1500 automatic mapping
- Modbus TCP / Modbus RTU integration
- PM modules must be used with the above IO heads
PLINK Headers (Head Units)
Select a header based on your host PLC and communication method. Click the header name to view details.
| Header Type | Product Features |
|---|---|
| Net IO Header |
Connects via Ethernet port and supports three protocols: enables short-distance expansion near devices or long-distance distributed remote IO. 1. S7-Smart Client Protocol (default): One end connects to the Smart host, the other to the Net IO header. Automatic mapping of PLINK module resources to the Smart host without programming. 2. S7-1200 or S7-1500 Client Protocol: Connects to 1200/1500 host. Automatic mapping without programming. 3. Modbus TCP Server Protocol: Works with any Modbus TCP client device (other PLCs, HMI, IPC, or custom software). |
| SB PLINK Header | Designed exclusively for original Smart SR/ST series hosts. Installs in the host’s signal board slot and connects to PLINK expansion modules. Automatic resource mapping to internal registers without programming. Suitable only for short-distance expansion. |
| DP PLINK Header | Designed exclusively for original Smart CR/CRs series hosts (no signal board slot). Connects to the host’s PORT0 and links PLINK expansion modules. Automatic resource mapping to internal registers without programming. Suitable only for short-distance expansion. |
| Modbus IO Header | Supports 485 Modbus RTU slave protocol for distributed remote IO scenarios. Connects to any Modbus RTU master (PLC, HMI, IPC, PC). Recommended for devices with only a 485 port; otherwise, use the Net IO header for Ethernet. |
Usage Guide
Build a PLINK system in three steps: select a header, connect PM modules, then configure communication/mapping.
- Net IO Header: Ethernet + multi-protocol (Smart/1200/1500/Modbus TCP).
- SB PLINK: for Smart SR/ST signal-board slot.
- DP PLINK: for Smart CR/CRs via PORT0.
- Modbus IO: RS485 Modbus RTU slave for universal masters.
- Digital I/O: DE / DR / QR / QT / DT series.
- Analog I/O: AE / AQ / AM series.
- Temperature: AR / AN / AT series.
- Arrange modules by signal type for easier wiring & maintenance.
- For Smart/1200/1500 client mode: automatic mapping (no programming).
- For Modbus TCP/RTU: set IP / slave ID and verify register access.
- Test each channel with real sensors/loads.
PM Digital I/O Modules
Expand discrete inputs and outputs for sensors, buttons, relays, and actuators. Click model names for product details.
PM Analog I/O Modules
Analog modules for industrial transmitters and control outputs (voltage/current). Click model names for details.
FAQ
Use Net IO Header for Ethernet projects and distributed IO. Use SB PLINK for Smart SR/ST hosts with a signal board slot. Use DP PLINK for Smart CR/CRs hosts via PORT0. Use Modbus IO Header when your master device is RS485 Modbus RTU only.
In Smart/1200/1500 client modes, PLINK resources can be mapped automatically without programming. In Modbus TCP/RTU mode, you read/write registers like a standard Modbus device.
Yes. Choose the header first, then combine PM modules based on your required signals and channels.
Need a Complete PLINK BOM?
Tell us your host PLC type (Smart / 1200 / 1500 / Modbus), required DI/DO/AI/AO/Temp channels, and cable distance. We’ll recommend the best header + PM module combination.
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