Citect Interface


Diagram of Hardware Connection



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Diagram of Hardware Connection


There are several options for how the PI Citect interface is run.

hardware diagram option 1

If the Citect host node is not heavily loaded then option 1, where the PI Citect interface and the PI API software are run directly on the Citect node is the recommended approach. It has the advantage of the interface running locally on the Citect node and so eliminates a network connection, but also supports buffering for when there are network or PI Server problems.



hardware diagram option 2

Option 2 also supports buffering; nevertheless, access to Citect is required including an additional computer. This configuration is well suited for situations where the Citect node is heavily loaded. It is also useful when several Citect nodes are to be scanned, as several copies of the Citect interface can run on the same PI Interface node.



hardware diagram option 3

With option 3 the interface runs directly on the PI Server. This is simple to install; however, it lacks any buffering and therefore it is not the recommended approach.



  1. Upgrading from Version 2.x to 3.x


Version 3.x represents some important and big changes to functionality and the features of the PI Citect interface. The most significant change is that point attribute Location1 now describes the interface ID and Location2 now describes if the point is an input or an output point. (Location1 and Location2 point attributes have been reversed.) You will need to edit all points for this interface to accommodate these changes. Make sure you do these point edits before implementing ICU changes.

Location1


Location1 indicates to which copy of the interface the point belongs. The value of this attribute must match the /id command-line parameter.

Location2


This field is used to specify whether a PI tag is an input tag (from Citect to PI) or an output tag (from PI to Citect).

0 – Input tag

1 – Output tag

You can use multiple methods like PI Tag configurator to edit the tags. Provided is a piconfig.exe utility example that will be available on every installation of the PI server. To quickly edit all the tags for the PI Citect Interface you can use this piconfig.exe script to handle all the changes. It works by exporting the Location1 and Location2 information for all the tags with Citect as the pointsource. Then it edits all the tags to the new format.

Open a command prompt and navigate to the pi server adm folder found at

C:\Program File\pi\adm run the piconfig.exe utility and enter this script (Replace the Citect pointsource with the pointsource of your citect tags.)


@table pipoint,classic

@mode list

@ostr tag,location2,location1

@select tag=*

@select pointsource=Citect

@outp locationswitch.csv

@ends
This will generate a locationswitch.csv file in the PI/adm directory. Check this list because all the tags here will be edited to reflect the location 1 and 2 changes. If you only want to edit an instance of the interface you’ll need to add another select statement to reflect this, i.e. @select location2=5 (with 5 being the designated interface instance id to change).
Once the file gets generated, the following script needs to be run to modify the tags.
piconfig

@table pipoint,classic

@mode edit

@istr tag,location1,location2

@input locationswitch.csv

@ends

Command line Parameter Changes


Obsolete Parameters

/ihost


/imode

/itag


/nopiwrite

/onlockup

/restartutil

/servicename

/wto

New Parameters

/CitectTS

/ReconnectRate

/citectdelay

/UsePIAPI

/V2
Optional UniInt phase 2 failover parameters


UniInt Failover Changes


The next big change is the deprecation of the interface specific failover which is replaced by UniInt Phase 2 (Hot, Warm and Cold) Failover. All interface specific failover command line parameters should be removed (if left they will be ignored). The ICU will handle this for you or you can do it yourself by editing the interface's .bat file. That includes /ihost /imode /itag /nopiwrite /onlockup /restartutil /servicename and /wto. In order to continue using failover you will need to refer to the UniInt Failover Configuration chapter to add the appropriate command line parameters, set up the shared file and two interfaces to support UniInt Failover.

  1. Principles of Operation


When the interface starts up, it receives several parameters from the interface startup file. These parameters define the PI Point Source code, interface id, and the set of Scan Class time periods to be available as well as other parameters as described in the section Command-line Parameters.

Log messages are recorded either in the PI log file or the PI application log file. The PI log file is named PI\log\pimsg_yymmdd.dat and is renewed daily.

The interface begins by searching the PI Point Database for all tags configured with the PointSource code specified in the interface startup file. If the interface identifier (/id=) has been specified as a command-line parameter, then the point configuration is checked to ensure the point has the same interface identifier. It then records these tags in dynamic group structures in the computer memory based on logical groupings (e.g. one list per scan class, per point type).

When the interface process has completed these initial tasks, it enters a permanent loop in which it processes input and output tags. This loop is repeated until the interface is stopped. The actions taken within this loop are described below.




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