Objectives
To provide a general understanding of how and what Omron devices support Simple Network Management Protocol (SNMP).
Introduction
SNMP is an application layer protocol designed specifically to monitor and manage network devices. Some Omron devices support SNMP functionality to improve network performance and increase reliability.
This article includes the following sections to provide a basic understanding of the functionality and supporting hardware for SNMP.
Content
SNMP (Simple Network Management Protocol) is a TCP/IP based protocol that is often included in many high-performance Ethernet devices. Some networks include a Network Management System (NMS) or SNMP Manager that is used to communicate with all SNMP enabled devices such as a CJ1W-EIP21 Unit or NJ series controller. Internal status information from the EtherNet/IP Unit can be passed to a SNMP Manager if enabled and configured properly.
The SNMP manager can provide a software interface between a person and the physical devices being managed on a network. A SNMP Manager requests and receives information from an SNMP Agent running in a network device such as:
- network protocol identification and statistics
- dynamic identification (discovery) of devices attached to the network
- hardware and software configuration data
- device performance and usage statistics
- device error and event messages
- program and application usage statistics
Enabling SNMP in an Omron device can allow critical operation status communications with a SNMP Manager. Status notification reports are sent when controllers are turned ON, links are established or when an SNMP agent fails to be authorized.
The following Omron devices supported SNMP*:
- CJ1W-EIP21
- CS1W-EIP21
- CJ2M-CPU3_
- CJ2H-CPU6_-EIP
- NJ-Series CPU (Built-in EtherNet/IP Port)
*When this article was created (June, 2014), these units supported SNMP. Contact your local Omron representative for more information about other units released after article creation.
An NJ-series Controller can be configured to provide network management information to an SNMP manager very easily. The following basic steps are detailed below.
In the Controller Setup, select Built-in EtherNet/IP Port Settings and SNMP Settings
Select Use for the SNMP service. The default port is 161.
Enter an IP address/host name for Recognition 1
In the image above, a PC's IP address is used that is running an SNMP MIB browser software that can query SNMP agents. This can be done for testing purposes.
Select Use for the SNMP trap
Provide details for Trap 1
Specify an IP address or host name
Select the proper SNMP version for compatibility with SNMP Manager.
Summary
Several Omron devices support SNMP functions that increase the stability and reliability of an application that relies on Ethernet communications. Understanding the basic SNMP fundamentals and how to configure a system will increase the performance of Ethernet communications.
References
See the following manuals for hardware specific information:
- NJ-series CPU Unit Built-in EtherNet/IP Port User's Manual (Cat. No. W506)
- SYSMAC CS and CJ Series EtherNet/IP Units Operation Manual (Cat. No. W465)
Glossary
Recognition 1/2: Set this to specify SNMP managers for which access is permitted.
Trap: When a failure or some other specific problem occurs, a status report called a trap is sent. This enables monitoring changes in status even if the SNMP manager does not monitor the built-in EtherNet/IP port periodically.
MIB: The MIB (Management Information Base) is a function of the Ethernet hardware that collects and provides information for the SNMP manager, such as Unit, interface, IP address, ICMP, TCP, UDP, and SNMP information.