M&M FDT 1.2.1 Online Specification
 6.11 Propagation of Changes


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6.1 DTM Peer To Peer Communication
6.1.1 Establish a Connection between DTM and Device
6.1.2 Asynchronous Connect
6.1.3 Asynchronous Disconnect
6.1.4 Asynchronous Transaction
6.2 Nested Communication
6.2.1 Generate Systemtopology
6.2.2 Establish a Connection between DTM and Device
6.2.3 Asynchronous Transaction
6.3 Topology Scan
6.3.1 Scan Network
6.3.2 Cancel Topology Scan
6.3.3 Provisional Scan Result Notifications
6.3.4 Scan for Communication Hardware
6.3.5 Manufacturer specific Device Identification
6.4 Registration of Protocol Specific FDT Schemas
6.5 Configuration of a Fieldbus Master
6.6 Starting and Releasing Applications
6.7 Channel Access
6.8 DCS Channel Assignment
6.9 Printing of DTM Specific Documents
6.10 Printing of Frame Application Specific Documents
6.11 Propagation of Changes
6.12 Locking
6.12.1 Locking for Non Synchronized DTMs
6.12.2 Locking for Synchronized DTMs
6.13 Instantiation and Release
6.13.1 Instantiation of a New DTM
6.13.2 Instantiation of an Existing DTM
6.13.3 Instantiation of a DTM User Interface
6.13.4 Release of a DTM User Interface
6.14 Persistent Storage of a DTM
6.14.1 State machine of instance data
6.14.1.1 Modifications
6.14.1.2 Persistence
6.14.2 Saving Instance Data of a DTM
6.14.3 Reload of a DTM Object for Another Instance
6.14.4 Copy and Versioning of a DTM Instance
6.15 Audit Trail
6.16 Comparison of Two Instance Data Sets
6.16.1 Comparison Without User Interface
6.16.2 Comparison With User Interface
6.17 Failsafe Data Access
6.18 Set or Modify Device Address With User Interface
6.19 Sets or Modifies Known Device Addresses Without User Interface
6.20 Display or Modify All Child Device Addresses With User Interface
6.21 Device Initiated Data Transfer
6.22 Starting and Releasing DTM User Interface in Modal Dialog
6.23 Parent Component Handling Redundant Slave
6.24 Initialization of a Channel ActiveX Control
6.24.1 Supports IFdtChannelActiveXControl2
6.24.2 Does Not Support IFdtChannelActiveXControl2
6.25 DTM Upgrade
6.25.1 Saving Data from a DTM to be Upgraded
6.25.2 Loading Data in the Replacement DTM
6.26 Usage of IDtmSingleDeviceDataAccess::ReadRequest / Write Request
6.27 Instantiation of DTM and BTM

6.11 Propagation of Changes

Within a multi user environment it is common, that more than one DTM have access to the same data set. To synchronize DTMs which are started by several users on different workplaces FDT provides a notification mechanism via OnParameterChanged(). Precondition for this event mechanism is that all changed data are stored by the DTM or by the Frame Application. All other DTMs have read access only. Furthermore all DTMs which are responsible for a device instance must have a common agreement about the contents and schema of the XML document send for propagation of changes. Tthe Frame Application only passes the document to all DTMs which have a reference to the same data set.


Used methods:
IDtmApplication::StartApplication()
IDtmEvents::OnParameterChanged()
IFdtEvents::OnParameterChanged()



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Last updated 2015-02-05 15:17
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