Menu

Omron CS1W-EIP21S CS-series EtherNet/IP unit in the shipping carton with the type label visible

Omron CS1W-EIP21S — EtherNet/IP Unit, Socket Services

SKU: CS1W-EIP21S

USD 290.00

CS-series EtherNet/IP unit with TCP/UDP socket services and four security features, 256 tag-data-link connections, 184,832-word capacity.

1-Year Warranty Full manufacturer warranty
Global Shipping Worldwide delivery available
Genuine Omron 100% authentic product
Ready to Ship Usually ships within 24h
In Stock

This item is available for immediate shipment from our warehouse.

Request Quote

Contact for pricing, bulk discounts, and shipping

Product Overview

The Omron CS1W-EIP21S is the EtherNet/IP communications unit for the CS1 series of PLCs. It adds an industrial Ethernet port to a CS1G, CS1H, CS1D, or NJ-series CPU, and sits as a CPU bus unit on the rack. The 'S' suffix distinguishes it from the discontinued CS1W-EIP21: the EIP21S adds a TCP/UDP socket service (for custom protocols like Modbus/TCP master / slave or barcode-reader polling) alongside EtherNet/IP, plus four security features — secure communication, user authentication, port-switch control, and IP packet filtering — that harden the unit against unauthorised access and malicious traffic on the plant network.

What the CS1W-EIP21S does on a CS1 rack

It runs EtherNet/IP tag data links with up to 256 connections across up to 256 nodes, with up to 722 words per connection kept consistent in a single scan, for a total of 184,832 words. This is enough to feed a line of VFDs, servo drives, remote I/O blocks, and HMIs in cyclic data without ladder code on either end. Above that, the FINS/TCP and FINS/UDP layers expose the CS1's memory areas for SCADA polling and message-mode reads / writes. The socket service lets you write a small ladder routine that opens TCP or UDP sockets to non-EtherNet/IP devices — barcode readers, weighing scales, third-party HMIs — and avoid adding a separate protocol-conversion gateway.

Sibling and replacement notes

The plain CS1W-EIP21 (without the S) was discontinued and is replaced by this SKU. For the smaller CJ1 / CJ2 / NJ series without CS1 expansion, the equivalent is the CJ1W-EIP21 (CJ-series EtherNet/IP unit) or CJ1W-EIP21S (newer CJ unit with the same socket-service / security features). For an Ethernet port without EtherNet/IP and with simple FINS-only messaging, the older CS1W-ETN21 covers lower-cost FINS communication.

Before ordering

Confirm there is a free CPU bus unit slot on the CS1 CPU rack or expansion rack — up to 8 CS1W-EIP21S units can be mounted per system. Configure the IP address, node number, and tag data links in CX-Programmer or via the rotary switches and DIP switches on the front of the unit. Power is drawn from the CS1 backplane (no external supply). The unit ships with a 25-word CIO area and 100-word DM area reserved for control bits, status flags, target-node info, and IP configuration.

Key Features

  • EtherNet/IP unit for CS-series PLCs (CPU bus unit)
  • 100Base-TX Ethernet port
  • Tag data links: 256 connections / 256 nodes, 722 words / connection, 184,832 words total
  • FINS/TCP and FINS/UDP for SCADA and Omron peer-to-peer communication
  • TCP / UDP socket service for custom protocols (Modbus/TCP, barcode reader, etc.) — the 'S' feature
  • Four security features: secure communication, user authentication, port control, IP packet filter
  • Mountable on CS1 CPU rack or expansion rack; up to 8 units per system
  • Operates with CS1G, CS1H, CS1D, and NJ-series CPUs
  • 25 CIO words / 100 DM words allocated per unit
  • SKU: CS1W-EIP21S
  • Series: CS1W-EIP21S

Best-Fit Applications

  • CS1H system exchanging cyclic process data with 30 VFDs and an NB-series HMI over EtherNet/IP
  • Retrofit of an existing CS1D cabinet adding native Ethernet without changing the CPU backplane
  • CS1G line controller that needs to poll a Modbus/TCP weighing scale from ladder — CS1W-EIP21S socket service avoids a separate gateway
  • NJ501 CPU feeding CS1W expansion racks with the EIP21S bridging NJ tag-data-links to legacy CS1 I/O
  • Plant network segmentation: enable IP filtering and user authentication on the CS1W-EIP21S to keep the office network off the control bus

Buying Checklist

  • Pick CS1W-EIP21S over the discontinued CS1W-EIP21 to get socket services and the four security features.
  • Pick CJ1W-EIP21S instead when the CPU is a CJ1 / CJ2 / NJ without CS1 expansion racks — the same logic and security features in a smaller form factor.
  • Pick CS1W-ETN21 when the cabinet only needs FINS messaging over Ethernet — it has EtherNet/IP support removed for cost.
  • Configure the tag data links in CX-Programmer or Network Configurator before powering the bus — start with one connection per device and grow once the network is live.
  • Use the rotary switches on the front of the unit to set node number 01-99 — never leave at default when shipping to a site with multiple units.

Technical Specifications

Model CS1W-EIP21S
Type CS-series CPU Bus Unit; 100Base-TX EtherNet/IP
Tag Data Link Capacity 184,832 words; 722 words / connection; 256 connections across 256 nodes
Higher-Level Protocols EtherNet/IP, FINS/TCP, FINS/UDP
Socket Service TCP / UDP open sockets via ladder (the 'S' feature)
Security Features Secure comms, user authentication, port control, IP packet filter
CIO / DM Words 25 CIO words + 100 DM words per unit (control + IP setup)
Power 5 VDC from CS1 backplane; no external supply
Mounting CS1 CPU or expansion rack; 8 units max per system
Compatible CPUs CS1G / CS1H / CS1D and NJ-series with CS1 expansion
Operating Temperature 0 to +55 °C
Approvals UL, CSA, CE (RCM)

FAQ for CS1W-EIP21S

What is the difference between CS1W-EIP21S and CS1W-EIP21?
The CS1W-EIP21S adds two things the older CS1W-EIP21 does not have: a TCP/UDP socket service (so the CS1 can act as a Modbus/TCP client / server or talk to barcode readers via standard sockets), and four security features (secure communication, user authentication, port-switch control, IP packet filter). Both units share the same EtherNet/IP tag-data-link engine, the same 256-connection capacity, and the same CS1 backplane form factor. The plain CS1W-EIP21 was discontinued — the CS1W-EIP21S is its specified replacement.
Can the CS1W-EIP21S work on a CJ-series rack or an NJ-series controller?
The CS1W-EIP21S is a CS-series CPU bus unit and physically only fits the CS1 rack or an expansion rack driven by a CS1 CPU. For the CJ1 / CJ2 family, use the CJ1W-EIP21S instead. NJ-series controllers (NJ101 / NJ301 / NJ501) accept the CS1W-EIP21S when they are set up to drive CS1 expansion racks — for native NJ communications, use the built-in EtherNet/IP port or an NX EtherCAT slave.
How is the unit configured?
Through CX-Programmer (for IP setup, target-node tables, and routing) or through the Network Configurator software (for tag data-link connections). The unit has a bank of rotary switches for node number and a small bank of DIP switches for IP-mode / boot-mode — set those before connecting the network cable. The configuration is saved in the unit's non-volatile memory so it survives power cycles.
How many tag data links can the CS1W-EIP21S handle?
256 connections of up to 722 words each, with up to 256 nodes total, for a combined 184,832 words. Tag-data-link data is refreshed per-connection (the connection-level consistency guarantee is per scan), so a single connection carrying the 722 words is delivered as a consistent batch even if the underlying network tries to interleave updates from other devices.

Similar Products

Explore related Omron models often viewed alongside this product.