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CS-series EtherNet/IP Unit


EtherNet/IP unit with tag data link capacity of 180,000 words or more

EtherNet/IP Unit Specifications

Item Specifications
Model number CS1W-EIP21/EIP21S
Type 100Base-TX *1
Applicable PLCs CS-series PLCs *2
Unit classification CS-series CPU Bus Unit
Mounting location CPU Rack or Expansion Rack
Number of Units that can be
8 max. (including Expansion Racks)
Allocated CIO Area
words (CPU Bus Unit
25 words/Unit (one unit number’s words)
These words contain control bits and flags, the target node PLC’s operating and
error information, Unit status, communications status, registered/normal target
node information, and FINS/TCP connection status.
Allocated DM Area
words (CPU Bus Unit
100 words/Unit (one unit number’s words)
These words contain the IP address display/setting area
User-set area Any usable data area words
Target node PLC’s operating and error information, and registered/normal target
node information
CPU Bus Unit System
Not used.
Non-volatile memory within
EtherNet/IP Unit (See note.)
The following settings are stored in the EtherNet/IP Unit’s non-volatile memory.
Note: Unlike the regular Ethernet Units, the CPU Bus Unit Setup Area in the CPU
Unit is not used for these settings.
1. Unit setup (communications settings for the EtherNet/IP Unit, such as the IP
address, DNS server settings, host name, baud rate, FINS/UDP settings, and FINS/
TCP settings)
2. Tag data link settings (device parameters)
3. User authentication settings (CS1W-EIP21S only)
4. Operation log (CS1W-EIP21S only)
Media access method CSMA/CD
Modulation method Baseband
Transmission paths Star form
Baud rate 100 Mbit/s (100Base-TX)
Transmission media Shielded twisted-pair (STP) cable
Categories: 100 Ω at 5, 5e
Transmission distance 100 m (distance between hub and node)
Number of cascade
There is no limitation when a switching hub is used.
Current consumption (Unit) CS1W-EIP21: 410 mA max. at 5 V DC
CS1W-EIP21S: 620 mA max. at 5 V DC
Weight CS1W-EIP21: 171 g max.
CS1W-EIP21S: 180 g max.
Dimensions 35 × 130 × 101mm (W × H × D)
Other general specifications Other specifications conform to the general specifications of the CS-series

*1. If tag data links are being used, use 100Base-TX. Otherwise, 10Base-T can be used, but this is not recommended.
*2. For the CS1W-EIP21S, the following CPU Units are supported.
  CS1G-CPU[][]H, CS1H-CPU[][]H, CS1D-CPU[][]HA/H, CS1D-CPU[][]SA/S, and CS1D-CPU[][]P

Communications Specifications

Item Specifications
Tag data
Number of connections 256
Packet interval
(refresh cycle)
0.5 to 10,000 ms (in 0.5-ms units)
Can be set independently for each connection.
(Data is refreshed over the network at the preset interval and
does not depend on the number of nodes.)
bandwidth per Unit
6,000 to 12,000 pps *1 *2
Note: Including the heartbeat.
Number of tag sets 256
Tag types CIO Area, DM Area, EM Area, Holding Area, and Work Area
Number of tags per
connection (= 1 tag set)
8 (7 tags when the tag set contains the PLC status)
Maximum link data size per node
(total size of all tags)
184,832 words
Maximum data size per
252 words or 722 words *3
Note: Data synchronicity is maintained within each connection.
Number of registrable
tag sets
(1 connection = 1 tag set)
Maximum size of 1 tag
722 words
(The PLC status uses 1 word when the tag set contains the PLC
Maximum number of
tags that can be
refreshed per CPU Unit
cycle *4
Output/Transmission (CPU to EtherNet/IP): 19
Input/Reception (EtherNet/IP to CPU): 20 *5
Data that can be
refreshed per CPU Unit
cycle *4
The layout of
the allocated CIO Area
words is the defauly *6
Output/Transmission (CPU to EtherNet/IP): 7,469 words
Input/Reception (EtherNet/IP to CPU): 7,469 words
Changing tag data link
parameters during
Supported *7
Multicast packet filter
function *8
Class 3 (connected) Number of connections: 128
UCMM (unconnected) Number of clients that can communicate at one time: 32 max.
Number of servers that can communicate at one time: 32 max.
CIP routing CS1W-EIP21/EIP21S, CJ1W-EIP21/EIP21S,
FINS service *9 FINS/UDP Supported
FINS/TCP 16 connections max.
SNMP Agent SNMPv1, SNMPv2c, SNMP trap
EtherNet/IP conformance test CS1W-EIP21S: CT17
CS1W-EIP21: CT11
Ethernet interface 10BASE-T or 100BASE-TX
Auto Negotiation or fixed settings

*1. In this case, pps means "packets per second" and indicates the number of packets that can be processed in one
*2. When using CS1W-EIP21S or CS1W-EIP21 with version 3.0 or later.   
  When using CS1W-EIP21 with version 2.1 or earlier, the allowed communications bandwidth per Unit is 6,000 pps.

*3. To use 505 to 1,444 bytes as the data size, the system must support the Large Forward Open standard (an optional CIP specification). The CS/CJ-series Units support this standard, but before connecting to nodes of other companies, confirm that those devices also support it.
*4. If the maximum data size is exceeded, the data refreshing with the CPU Unit will extend over two or more cycles.
*5. If status layout is set to user settings, the maximum number of tags is as follows.

Condition Output/Transmission Input/ Reception
CS1W-EIP21S 18 18
CS1W-EIP21 19 19

*6. The table below shows value when the layout type is User defined.

Data (words) that can be refleshed
per CPU Unit cycle
Output/Transmission 7405 7321
Input/Reception 7405 7385

*7. If parameters are changed in the EtherNet/IP Unit, however, the EtherNet/IP Unit will be restarted. When other nodes are communicating with the affected node, the communications will temporarily time out and automatically recover later.
*8. Because the EtherNet/IP Unit is equipped with an IGMP client, unnecessary multicast packets can be filtered by using a switching hub that supports IGMP snooping.
*9. The EtherNet/IP Unit uses the TCP/UDP port numbers shown in the following table.

Service Protocol Port number Remarks
Tag data links UDP 2222 The port number is fixed.
Class 3, UCMM TCP/UDP 44818
Secure Comm TCP 443 The port number is fixed.
It is supported by the CS1W-EIP21S only.
FINS/UDP service UDP 9600 Port numbers in the Unit Setup can be changed with
the CX-Programmer.
FINS/TCP service TCP 9600
FTP TCP 20, 21
SNMP trap UDP 162

Network Configurator Requirements

The Network Configurator is a software package designed for building, setting, and controlling a multi-vendor EtherNet/IP Network using OMRON's EtherNet/IP. It is included in CX-One.
CS1W-EIP21 EtherNet/IP Unit. Network Configurator version 3.0 or higher is included with CX-One version 3.0 or higher.
CS1W-EIP21S EtherNet/IP Unit. Network Configurator version 3.73 or higher is included with CX-One version 4.61 or higher.
The Network Configurator provides the following functions for building, setting, and controlling EtherNet/IP.

Item Specification
System Requirements Refer to the CX-One Catalog (Cat. No. R134), visit your local OMRON website.
Serial interface CPU Unit’s Peripheral or RS-232C port CPU Unit’s USB or RS-232C port
Ethernet interface EtherNet/IP Unit’s Ethernet port CPU Unit’s Ethernet port
EtherNet/IP Unit’s Ethernet port
Location on Network A single node address is used (only when directly connected to EtherNet/IP).
Number of Units that can be
connected to Network
A single Network Configurator per Network
(More than one Configurator cannot be used in the same system.)
Network control
•The Network configuration can be created and edited regardless of whether the
Network Configurator is online or offline.
•The Network configuration can be read from a file or the network.
The EDS files used by the Network Configurator can be installed and deleted.
Supported file formats Configurator network configuration files (*.ncf)
Configuration files (*.ncf) created using the Network Configurator for EtherNet/IP
(version 2) can be imported by selecting External Data - Import from the File Menu.