Supported features

The following table describes features that this interface supports. Some features are described in more detail after the table.

The Interface is designed to run on the above mentioned Microsoft Windows operating systems and their associated service packs. Please contact Technical Support for more information.

• Uses PI SDK

  The PI SDK and the PI API are bundled together must be installed on each PI Interface node. This interface does not specifically make PI SDK calls.

• Source of Time stamps

  All values that are written to the snapshot or archive use the system time from the PI home node.

• UniInt-based

  UniInt stands for Universal Interface. UniInt is not a separate product or file; it is an AVEVA-developed template used by developers and is integrated into many interfaces, including this interface. The purpose of UniInt is to keep a consistent feature set and behavior across as many of our interfaces as possible. It also allows for the very rapid development of new interfaces. In any UniInt-based interface, the interface uses some of the UniInt-supplied configuration parameters and some interface-specific parameters. UniInt is constantly being upgraded with new options and features.

  The PI Universal Interface (UniInt) Framework User Guide is a supplement to this manual.

• Disconnected start-up

  The ModbusE interface is built with a version of UniInt that supports disconnected start-up. Disconnected start-up is the ability to start the interface without a connection to the Data Archive. This functionality is enabled by adding /cachemode to the list of start-up parameters or by enabling disconnected startup using the ICU.

• SetDeviceStatus

  The interface supports UniInt device status tags. The device status Health tag has the string [UI_DEVSTAT] in the extended descriptor (Exdesc) point attribute. Refer to the PI Universal Interface (UniInt) Framework User Guide for more information on how to configure health points. Alternatively, health tags can be configured with the PI Interface configuration utility.

  Device status tags can be configured to monitor the status of the devices to which the interface connects. Strings of the following form can be written to the device status tag. Note that the "# |" at the beginning of each error string is for internal use for an application that parses this string.

  • Good

    This value indicates that the Interface is able to connect to all of the devices referenced in the Interface's point configuration. A value of "good" does not mean that all tags are receiving good values, but it is a good indication that there are no hardware or network problems.

  • 1 | Starting

    The interface will remain in this status until it has successfully collected data from its first scan. Interfaces that collect data infrequently may stay in this status for a long time.

  • Zero devices are currently communicating with the interface

    This value indicates that the Interface cannot communicate with any of the devices.

  • # device(s) failed all of their retries while requesting data

    This value indicates that the Interface cannot communicate with some of the devices. The number of devices that failed their retries will be recorded and logged.

  • 4 | Intf Shutdown

    The Interface has shut down.

• Failover

  UniInt Phase 2 failover provides support for cold, warm, or hot failover configurations. The Phase 2 hot failover results in a no data loss solution for bi-directional data transfer between the Data Archive and the data source given a single point of failure in the system architecture similar to Phase 1. However, in warm and cold failover configurations, you can expect a small period of data loss during a single point of failure transition. This failover solution requires that two copies of the interface be installed on different interface nodes collecting data simultaneously from a single data source. Phase 2 failover requires each interface have access to a shared data file. Failover operation is automatic and operates with no user interaction. Each interface participating in failover has the ability to monitor and determine liveliness and failover status. To assist in administering system operations, the ability to manually trigger failover to a desired interface is also supported by the failover scheme.

  The failover scheme is described in detail in the PI Universal Interface (UniInt) Framework User Guide, which is a supplement to this manual. This interface supports UniInt Failover (phase 2 cold, warm and hot).

• Additional PI Software Included with Interface

  This interface comes with support utilities for configuration purposes and upgrading from previous versions of the interface. These utilities are described in detail in later chapters of this document:

  • The Modbus Ethernet Interface Configurator is used to configure the interface and each Ethernet node that the interface supports.

  • The Modbus Program for Interface Diagnostics is used to determine and test point configurations with a Modbus device.