Error and warning messages are logged to the Pipc.log file located in the Pipc\Dat directory of the PC that the interface is running on. The interface has the option of writing debugging and information messages to this log file. For more information about configuring the interface to do this, see the description of “/db” and “/df” in the Interface Startup File section on page 15.
Each message is preceded by the local timestamp of the computer it is running on. The file is used by multiple PI client applications for similar purposes as the interface. To distinguish which messages are from the interface each message is preceded by a header. The format of such a message is
dd-mmm-yy hh:mm:ss
YGW Id_String> Message
where Id_String is the string passed to the interface by the “/id” command line argument. See the Interface Startup File section on page 17 for more details. Following is an example of a message in the log file from the interface that uses the command line argument /id=Tower.
31-Jul-98 09:05:03
YGW Tower> Hardware initialization error, Intf halted
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The integrity of the point configuration is checked during the interface startup and when new points are added to PI system. If an error is detected, corresponding error messages are logged to the log file and the point is not added to the interface point list.
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A point will receive a status of BAD_INPUT for the following reasons:
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An error value (-99999999) was returned from the DCS system.
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An obstruction occurred on the DCS system.
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An error will occur if the specified instrument tag does not exist on the Yokogawa DCS system.
The error return code is in the log file. If this error occurs, verify the point definition of the tag in question.
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R_OVER_DIG is written to a PI2 digital tag if the value from the DCS is not between the starting digital state code and the number of digital states. R_OVER_DIG is written to a PI3 digital tag if the value from the DCS is greater than the number of digital states defined in the digital state set for that tag. BAD_DIGSTATE is written when the digital state string from the DCS does not exist in the digital state table (PI2) or the digital state set for that tag (PI3).
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IO_TIMEOUT is written to a tag if a time out is detected between the interface and the DCS system. CONN_CLOSED is written when the connection with the gateway is closed. In this case, the interface logs an error message in the log files and stops retrieving data for the scan class which the error occurred on. The interface then resumes scanning starting with the next scan class. The interface will try to initialise the communication after a time out has been detected or the communication with DCS system is closed. Unless there are the obstructions, if the interface detects a connect error it will write CONN_CLOSED for TCP/IP communication. Correspondingly, if the interface detects an initialisation error, INIT_ERROR will be written for TTY.
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When the interface can not communicate with DCS system, the interface must be restarted after the reasons for the communication failure have been resolved. You can use the test programs to make sure that the path of communication is open prior to starting the interface (see page 23). YGI_Test.exe is used if communication is TTY or via TCP/IP in character mode. YGI_TestB.exe is used if communication is via TCP/IP in binary mode.
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For Centum V and Centum XL the user can define a maximum of 8192 points to blocks for one Yokogawa DCS system (maximum of 32 points per block and a maximum of 256 blocks). For Micro XL the maximum number of blocks definable depends on the memory available on the DCS. If the user tries to define more than the maximum number of points to blocks, the interface will write NO_BLOCK to all points exceeding the limit. The interface will refuse those points and the data of these points will not be retrieved. The interface uses a single block with a single scan class. BAD_BLOCK is written to a point if an error has occurred in its block definition.
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When the integer value from the DCS system is less than 0, the status INT_MINUS is written to the point. The point should be defined as point type Real and high precision if there is a possibility that values will be less than 0. This will result in the value instead of the digital state INT_MINUS being stored in PI (see the Tag Definition section on page 11).
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If an output point is set to a value outside of its digital state range, the interface will not output the value to the DCS and instead writes NOT_OUTPUT to the PI point. NOT_OUTPUT is only written if it has an associated source tag.
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The interface only will output data to the DCS if its data type has been specified in the file YGW_OItem_#.txt. The interface checks the value in the location 1 parameter to determine whether to update the DCS or not. If the interface cannot output the value to the DCS, NOT_OUTPUT is written to the output point if it has an associated source tag.
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If the interface fails to update DCS data, it writes OUTPUT_ERR when a communication error has occurred and it writes FAILED when the DCS system has returned an error. Again, these states are only written to the point if it has an associated source tag.
PI System Databases
The interface collects data from the Yokogawa gateway via TCP/IP socket calls. For every Yokogawa point type that data is to be collected for, corresponding tags must be defined within PI. Data for Multiple Yokogawa tag types can be collected but each type must correspond to a single PI point. For example, FIC00413.PV, FIC00413.SP and FIC00413.LOOP can all be collected using three separate PI tags.
Each PI point has a set of fields that are used by the interface and need to be configured for the interface to operate correctly. Digital states should be defined for recording discrete data.
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