Pi bacnet Interface

I/O Rate Point

An I/O Rate point measures the rate at which the Interface writes data to its input tags. The value of an I/O Rate point represents a 10-minute average of the total number of values per minute that the Interface sends to the PI Server.

When the Interface starts, it writes 0 to the I/O Rate point. After running for ten minutes, the Interface writes the I/O Rate value. The Interface continues to write a value every 10 minutes. When the Interface stops, it writes 0.

The ICU allows you to create one I/O Rate point for each copy of this Interface. Select this Interface from the Interface drop-down list, click IO Rate in the parameter category pane, and check Enable IORates for this Interface.

As the preceding picture shows, the ICU suggests an Event Counter number and a Tagname for the I/O Rate Point. Click the Save button to save the settings and create the I/O Rate point. Click the Apply button to apply the changes to this copy of the Interface.

You need to restart the Interface in order for it to write a value to the newly created I/O Rate point. Restart the Interface by clicking the Restart button:

(The reason you need to restart the Interface is that the PointSource attribute of an I/O Rate point is Lab.)

To confirm that the Interface recognizes the I/O Rate Point, look in the pipc.log for a message such as:

PI-ModBus 1> IORATE: tag sy.io.etamp390.ModbusE1 configured.

To see the I/O Rate point’s current value (snapshot), click the Refresh snapshot button:

Enable IORates for this Interface

The Enable IORates for this interface check box enables or disables I/O Rates for the current interface. To disable I/O Rates for the selected interface, uncheck this box. To enable I/O Rates for the selected interface, check this box.

Event Counter

The Event Counter correlates a tag specified in the iorates.dat file with this copy of the interface. The command-line equivalent is /ec=x, where x is the same number that is assigned to a tag name in the iorates.dat file.

Tagname

The tag name listed under the Tagname column is the name of the I/O Rate tag.

Tag Status

The Tag Status column indicates whether the I/O Rate tag exists in PI. The possible states are:

• 
  Created – This status indicates that the tag exist in PI
  
• 
  Not Created – This status indicates that the tag does not yet exist in PI
  
• 
  Deleted – This status indicates that the tag has just been deleted
  
• 
  Unknown – This status indicates that the PI ICU is not able to access the PI Server
  

In File

The In File column indicates whether the I/O Rate tag listed in the tag name and the event counter is in the IORates.dat file. The possible states are:

• 
  Yes – This status indicates that the tag name and event counter are in the IORates.dat file
  
• 
  No – This status indicates that the tag name and event counter are not in the IORates.dat file
  

Snapshot

The Snapshot column holds the snapshot value of the I/O Rate tag, if the I/O Rate tag exists in PI. The Snapshot column is updated when the IORates/Status Tags tab is clicked, and when the Interface is first loaded.

Right Mouse Button Menu Options

Create

Create the suggested I/O Rate tag with the tag name indicated in the Tagname column.

Delete

Delete the I/O Rate tag listed in the Tagname column.

Rename

Allow the user to specify a new name for the I/O Rate tag listed in the Tagname column.

Add to File

Add the tag to the IORates.dat file with the event counter listed in the Event Counter Column.

Search

Allow the user to search the PI Server for a previously defined I/O Rate tag.

Interface Status Point

The PI Interface Status Utility (ISU) alerts you when an interface is not currently writing data to the PI Server. This situation commonly occurs if

• 
  the monitored interface is running on an Interface Node, but the Interface Node cannot communicate with the PI Server; or
  
• 
  the monitored interface is not running, but it failed to write at shutdown a System state such as Intf Shut.
  

The ISU works by periodically looking at the timestamp of a Watchdog Tag. The Watchdog Tag is a tag whose value a monitored interface (such as this Interface) frequently updates. The Watchdog Tag has its excdev, excmin, and excmax point attributes set to 0. So, a non-changing timestamp for the Watchdog Tag indicates that the monitored interface is not writing data.

Please see the Interface Status Interface to the PI System for complete information on using the ISU. PI Interface Status runs only on a PI Server Node.

If you have used the ICU to configure the PI Interface Status Utility on the PI Server Node, the ICU allows you to create the appropriate ISU point. Select this Interface from the Interface drop-down list and click Interface Status in the parameter category pane. Right click on the ISU tag definition window to bring up the context menu:

Click Create to create the ISU tag.

Use the Tag Search button to select a Watchdog Tag. (Recall that the Watchdog Tag is one of the points for which this Interface collects data.)

Select a Scan frequency from the drop-down list box. This Scan frequency is the interval at which the ISU monitors the Watchdog Tag. For optimal performance, choose a Scan frequency that is less frequent than the majority of the scan rates for this Interface’s points. For example, if this Interface scans most of its points every 30 seconds, choose a Scan frequency of 60 seconds. If this Interface scans most of its points every second, choose a Scan frequency of 10 seconds.

If the Tag Status indicates that the ISU tag is Incorrect, right click to enable the context menu and select Correct.

Note: The PI Interface Status Utility – and not this Interface – is responsible for updating the ISU tag. So, make sure that the PI Interface Status Utility is running correctly.