The new iSNMP driver suite by Kepware

Specific

Specific Driver Features

iSNMP Suite provides valuable insight into the performance of a variety of industrial control system networks. The controllers, software, and underlying control network make up a modern control system. The entire system can become unreliable without stable performance from all three components. With iSNMP Suite you can monitor and analyze your plant Ethernet-based network from within your existing HMI package and never have to rely on blind faith that the network is performing to specifications.

The new SNMP driver also provides convenient "Specialty tags" to help users know more than the current value of a single polled OID. The tags include: History tags, Events tags, Table Offsets, and ScanFloor tags.

Historical Data Attributes – Previous Value, Delta Time, Moving Average

Historical values are generated by the SNMP driver (not the remote Agent/device) when an OID has valid historical modifiers appended to it.

Events Tags – Events_001, Events_001_001, Events_001_FieldCnt, Events_Count

A FIFO-based queue to receive Traps / Notifications from previously configured Agents.

Table Offsets – OID[1]

Table access is accomplished by enumerating columns of a table. The SNMP Device driver uses an array-like notation for Table access.

ScanFloor property – _ScanRateFloor, _ScanRateFloorLock

SNMP devices are typically scanned at much slower rates than other controls equipment. Scanning an SNMP device too quickly may result in degraded device performance. The Scan Rate Floor has been added to prevent users from inadvertently overloading Agent/devices with read requests in the order of milliseconds.

The Scan Rate Floor is the minimum rate to scan SNMP devices. The default is 1000 milliseconds. When set (to a non-zero value) the SNMP driver will never scan the remote device more often than the specified scan rate. Note that an OPC client can still poll the server and obtain the last read value at a much faster OPC Group Update Rate. Finally, the 'Lock' option will lock the Scan Rate for this device to the given value. When Locked, the driver will always poll at the Scan Rate setting regardless of OPC client update rates that are below or above this rate.

SNMP Traps Support

Many SNMP-manageable devices can be configured to send unsolicited data to network management software systems such as iSNMP. By configuring an SNMP device to send data without being "polled" such as when a critical system tag goes into an unfavorable state, you can reduce the need for "polling" the network device. iSNMP supports receiving SNMP Trap data via Events tags as well as through defined Trap OIDs.