Case 1: Single PI Tag Retrieving Multiple Fields from a DAANG Block

Case 1: Single PI Tag Retrieving Multiple Fields from a DAANG Block

Data Field	Definition
7	Auto/Manual
4	Alarm Level
2	High Alarm
3	Low Alarm
17	High Deviation Alarm

The resultant value would be built from the value in the data field or fields. Additionally, the place value assigned to each data piece depends upon its position in the extended descriptor parameter list. Thus, assuming that the Alarm Level has a value of 3, and the High Deviation Alarm is ON, the value sent to the PI tag would be as follows:

Data Field	Field Length	Bailey Value	Position in PI Value	PI Value
Auto/Manual	1	0	bit 0	0
AlarmLeve1	2	3	bits 1, 2	6
High Alarm	1	0	bit 3	0
Low Alarm	1	0	bit 4	0
High Deviation Alarm	1	1	bit 5	32
Value for this PI Tag			00100110	38

The sum of the bit length for all the extracted fields cannot exceed 15 for each tag. An error will be printed in the log file if more than that is specified. Specific data fields may be duplicated within a single tag.

Case 2: Multiple PI Tags for this Bailey Block Address and Point Type

Each tag retrieves single or multiple fields from a DAANG block. The location parameters for each of these tags will be the same; however, they will have different extended descriptors. For example, tag 1 might have an extended descriptor /BLY=7,17, and tag 2 might have an extended descriptor, /BLY=4,2,3.
Note: Even though there are multiple PI tags, the interface will only retrieve the data once from Bailey and push the correct values into the correct tags.

Performance Points

Performance Points are not supported by this interface.

Scan

By default, the Scan attribute has a value of 1, which means that scanning is turned on for the point. Setting the scan attribute to 0 turns scanning off. If the scan attribute is 0 when the interface starts, SCAN OFF will be written to the PI point. If the scan attribute is changed from 1 to 0 while the interface is running, SCAN OFF will also be written to the PI point after the point edit is detected by the interface.
There is one other situation, which is independent of the Scan attribute, where UniInt will write SCAN OFF to a PI point. If a point that is currently loaded by the interface is edited so that the point is no longer valid for the interface, the point will be removed from the interface, and SCAN OFF will be written to the point. For example, if the PointSource of a PI point that is currently loaded by the interface is changed, the point will be removed from the interface and SCAN OFF will be written to the point.

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