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ABB Masterbus networks contain particular methods for data exchange between nodes. The main philosophy adopted uses a controller as the central part of all information, containing control logic and alarm or event processing as well.

All control strategy and information is created by declaration and interaction among blocks, which can have several types. Each particular instance of a block is formed by a name, such as "AI_123", and an identifier known as LF (Logical File) and LR (Logical Register). Both LF and LR identifiers are integers uniquely identifying a block instance.

However, users do not need to know the LF and LR identifiers for each block. They can import block names, descriptions, types, and LF and LR identifiers from ABB ASCII files to Elipse E3, Elipse Power, or Elipse Water Tags directly, open them in Excel and then export them to Elipse E3, Elipse Power, or Elipse Water, or even create an MB300_XX.ini file manually. This file is then used by this Driver to map a block name to its type and LF and LR identifiers.

After starting, if the file MB300_XX.ini is not found for a particular node referenced at least in one Tag, this Driver creates one and performs a translation request for each referenced block. The ABB Controller sends in its response the block type and LF and LR identifiers, which are then saved to that INI file.

After a block is saved as translated in an INI file, users can open Tag Browser window to create Tags automatically.

For every block, there is a special Tag called UpdateMode that indicates or defines the way that particular block is updated. This Tag's Value property is formed by the components SubscriptionType and AccessType, according to the next formula.

SubscriptionType * 10 + AccessType

 

•SubscriptionType:

•0 - Process Event: This Driver waits for event messages from the Controller to update block values

•1 - Demand: A poll is performed every time an update is requested through a writing operation to the UpdateMode Tag

•2 - Event: If event handling is enabled for the object on the Controller, an update is received every time the status word changes or an order is performed

•3, 5, 6 - Cyclic: Creates cyclic subscriptions of 1 (one), 3 (three), or 9 (nine) seconds, respectively. Updates are received until an unsubscribe is performed, by writing 0 (zero, Process Event) to the UpdateMode Tag

•AccessType: Indicates which block parameters are included in the response when this Driver performs a read request or a subscription. Access types usually range from 1 (one) to 4 (four), increasing the number of reported properties. Possible values are the following:

•1 (one) or 2 (two) for DI, DO, DAT, and TEXT object types

•1 (one) to 3 (three) for the AO object type

•1 (one) to 4 (four) for all other object types

 

The default value (start up) for the UpdateMode Tag is 1 (one), which means a subscription type equal to 0 (zero) and an access type equal to 1 (one). Please check topic Block Tag Reference for information on which access type to use to receive updates for each specific variable.