Dynagraph Card Data Group
The OPC Lufkin EIE "Dynagraph Card" (DynaCard) data group enables the retrieval of dynagraph card data using a plugin developed by Kepware. The XML of each "Dynagraph Card" data group contains a number of data group elements. The DataGroupElement elements define data used by CygNet; the dgordinals element defines a list that specifies data group ordinal numbers along with corresponding card names.
See Card Types for more information.
"Dynagraph Card" data groups for the OPC Lufkin EIE can be registered with an OPC server. Because a dynagraph card is a complex object that uses data from multiple OPC items, OPC callbacks are not allowed. Note that if a single value changes, a callback containing just that value is insufficient to create a complete dynagraph card. Specifically, a "Dynagraph Card" data group can be assigned to the OPC group definitions With matching properties, Specific for this data group, or None (temporary). See Data Groups and Assigning a Data Group to an OPC Group for more information.
If the data group is assigned to the OPC group With matching properties or Specific for this data group, the data group is registered with the OPC server in such a way that it gets one card with both surface and downhole data. This has the advantage of allowing the OPC to poll for the most recent cards on its own schedule. These cards are then available to get very efficiently from the OPC cache. Note that requesting a 5-card buffer or only surface data will cause a new temporary instance of the data group to be created on the OPC server. It will be destroyed after polling is completed.
The OPC Lufkin EIE "Dynagraph Card" data group can be used to read a single card or a 5-card buffer. The number of cards available varies by card type, but is either 1 or 5. Note that if a user requests three Current cards, five will be returned from the device and all five will be stored.
The OPC Lufkin EIE "Dynagraph Card" data group supports seven card types. Numbers following the name indicate the number of cards stored on the device:
- 0 — Current Card: Specifies the most recent stroke. 1 or 5
- 1 — Shutdown Card: Specifies a card when a normal pump-off is detected. 1 (set 0) or 5 (sets 1 and 2)
- 2 — Pumpup Card: Specifies a card when a unit starts again after having "pumped up". 1
- 3 — Reference Card: Specifies a quick reference or snapshot of a dynagraph card, or any type of card from the associated remote device, if one is available, that is stored for reference in the CygNet system. 1
- 4 — Start Card: Specifies a card taken when a unit is configured. Used as a baseline. 1
- 6 — Alarm Card: An alarm card is created whenever an alarm condition is met in a field device. Such a condition is typically treated as less severe than a fault, which creates a failure card. 5
- 7 — Failure Card: A failure card is created whenever a fault condition is met in a field device. Such a condition is typically treated as more severe than an alarm, which creates an alarm card. 5
