Bailey Infi90 Interface to the pi system

Bailey Infi90 Interface to the PI System

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Principles of Operation
When the Infi90 runs, it begins by searching the PI Server for points that it should service. In particular, it looks for points whose PointSource attribute matches the
–ps
startup command parameter. For these potential points, the Interface then checks the Location codes attributes to determine point validity.
Next, the Interface opens the COM port to establish connection to the CIU. The program sends the CIU restart command, and establishes and connects all the points. Informational messages are sent to the PIPC.LOG at successful restart and at the end of the point establishment phase. The point establishment phase may last from less than a minute to more than ten minutes, depending on the number of points that the Interface is servicing. Normally, the Interface can establish ten points in one second.
After all the points have been established and connected, the program begins the loop to read Net90/Infi90 exceptions and send outputs. The startup parameters
–delay_and_cnt_determine_the_rate_at_which_the_Interface_polls_the_CIU._The_Interface_uses_the_following_algorithm_read_exceptions_until_cnt'>–delay
and
cnt
determine the rate at which the Interface polls the CIU. The Interface uses the following algorithm read exceptions until
cnt
consecutive reads or the number of exceptions received in a read is less than half the read capacity read miscellaneous status exceptions until
cnt
reads or the number of exceptions received in a read is less half of the read capacity check the PI Server for new snapshot values for the output source points. If there are, send those output values to the Net90/Infi90.
 delay for
–delay
seconds or check for PI point database updates if the timesync parameter (
–tsync
) is positive and thirty minutes have passed since the last time synchronization, then do time synchronization
For CIU04s, the algorithm is the similar. The only difference is that reading exceptions and reading miscellaneous status exceptions are combined into a single command.
The interface program periodically checks for changes in the PI point database and automatically accounts for the modification, addition, and deletion of points. Thus, there is no need fora program restart if interface points are edited. Each time the interface processes a point change, it writes a message to the PIPC.LOG. Hence, the user can trace the progress on the point database change.
However, it may take sometime for the program to pickup all the changes when a large number of tags are changed. Accordingly, if the user has changed a large number of points, it will be faster for the changes to take effect if the user restarts the interface.
If the interface program hasten consecutive IO errors, it will try to restart the CIU. All communication errors will be reported to the PIPC.LOG file. Consecutive errors of the same type are reported to the log file only once.
The CIU commands used by the Infi90 interface are restart CIU
 establish point establish report

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