Remote IO — Siemens S7-1200/1500 Connection

Overview

The SMX-RNS20 Remote IO feature can connect to Siemens S7-1200 and S7-1500 PLCs using the Siemens S7 (ISO-on-TCP) driver. This allows the device to read/write DB (Data Block), M (Memory), I (Input), and Q (Output) areas without a VPN or open firewall rules.

PLC Configuration

In TIA Portal, make sure the following two settings are configured:

1. Disable Optimized block access on all Data Blocks that Remote IO will read. Right-click the DB → Properties → Attributes → uncheck “Optimized block access”.

TIA Portal — uncheck “Optimized block access” in the Data Block properties

2. Enable PUT/GET communication. In PLC properties → Protection & Security → Connection mechanisms → check “Permit access with PUT/GET communication from remote partner”.

TIA Portal — enable PUT/GET access in CPU Protection & Security settings

The PLC must also have a static IP address on the same LAN subnet as the SMX-RNS20.

SMX-RNS20 Remote IO Configuration

1. Log in to the SMX-RNS20 web interface and navigate to Remote IO → Connections.
2. Click Add Connection and select Driver: Siemens S7.
3. Enter the PLC’s IP address, Rack (usually 0), and Slot (usually 1 for S7-1200, 0 for S7-1500).
4. Add the data points you want to read: select Area (DB, M, I, Q), enter DB number (for DB area), Offset, and Data type.
5. Set the scan interval and save the configuration. The SMX will begin polling the PLC.
6. View live values under Remote IO → Monitor.