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Reading an Event Buffer from GE PAC RX7 Controllers |
An event buffer can be read using Event-reported Tags, Event-reported Tags by point, and Real-time Tags.
Event-reported Tags return, at each reading operation, all events stored in this Driver's internal buffer, and they can be configured by Strings or numerically.
•Device: "<slave id>:"
•Item: "gesoe0.<Base address of an event stack>"
To read an event buffer from GE PAC RX7 using numerical configuration, users must define, on this Driver's configuration window, an operation that uses as its reading function the special function GE SOE. Its data type must be defined as GE_events.
•B1: Slave ID
•B2: Code of the operation defined with GE SOE function
•B3: 0 (zero)
•B4: Base address of PLC's event stack
At each scan on this Tag, this Driver checks if there are events on controller's buffer. If there are events, this Driver starts an event-reading thread, which is executed in background, not blocking the scan of all other Tags. After finishing the reading of this Driver's buffer, this event-reported Tag returns the set of events read on that scan.
Returned events generate a sequence of OnRead events on this Tag. For each read event, E3 or Elipse Power updates Tag fields, the Element values and timestamps, with values from a certain event, and calls the OnRead event once. This event's script must be defined by users, and it is generally used to insert Tag's data in a Historic.
Every event is represented by a Block with two Elements, with its Timestamp field read from a device. Fields from the respective reading Block Tag are displayed on the next table.
Block Tag fields
Offset |
Meaning |
Data Type |
Range of Values |
|---|---|---|---|
0 |
Point identification |
Byte |
Between 0 (zero) and 15 |
1 |
Point status |
Byte |
Between 0 (zero) and 1 (one) |
For more information about event-reported Tags, please check the specific topic on E3 User's Manual.
IMPORTANT |
When reading mass memory events in event-reported Tags in E3 or Elipse Power, disable Tag's dead band, that is, the EnableDeadBand property configured as False, and also the linked Historic object, that is, the DeadBand property equal to zero, to avoid loosing events with near values. It is also important to disable historic by scan, that is, in E3 or Elipse Power configure the ScanTime property as 0 (zero). This ensures that new events are only stored using the WriteRecord method, executed on Tag's OnRead event, avoiding duplication of events. |
Starting with version 2.5 of this Driver, users can use a new Tag to download events from a specific point.
This Tags works as the previous one, except that it returns only events from a specific point.
Different from the previous event, the returned value only contains a single Element with a status value of a point, so that only one Tag can be used. This Tag must be configured as follows:
•Device: "<Slave Id>:"
•Item: "gesoe<200 + Point's index>.<base address of event queue>"
•N1: Slave ID
•N2: Code of the operation defined with GE SOE function
•N3: 200 + Point's index, such as configuring the N3 parameter as 202 for point 2 (two)
•N4: Base address of PLC's event stack
For more information about event-reported Tags, please check the specific topic on E3 User's Manual.
These Tags return the most recent event already read for a specific point. These events are stored on this Driver's internal memory for each PLC's event reading, with their respective timestamps read from the device. This Tag uses the following parameters:
•Device: "<Slave Id>:"
•Item: "gesoe<100 + Point's index>.<base address of event queue>"
•N1: Slave ID
•N2: Operation Code
•N3: 100 + Point's index
•N4: Base address of PLC's event stack
•Value: Point's status