PI Interface for Bailey Infi90

Introduction
6

Option 2

PI Interface for Bailey Infi90
7
Chapter 2.
Principles of Operation
When the BaInfi90 interface 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
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

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