FieldServer FS-8700-47 instruction manual Appendix A.5. DLL Layer Functionality in the Master

FS-8700-47 DNP 3.0 Driver Manual Page 27 of 51

•If required sets flags for

•Map Descriptor matching,

•fetch/store function calls

•and/or response function call

•Signals Chan idle the outgoing app layer message needs to be processed.

Master Idle • Looks for signals from chan idle that a message has been received

•Processes Map Descriptors and forms read/write messages

•Signals Chan idle the outgoing app layer message needs to be processed.

Appendix A.5. DLL Layer Functionality in the Master

The DNP Primer provided by dnp.org describes the DLL layer requests for confirmation as optional and suggests that it is not often employed. Our driver never asks for DLL layer confirmations. Thus the DLL layer functions as a mere wrapper/unwrapper layer. It wraps user data with a header and CRC's but does not perform node-node confirmations.

The only DLL layer functions which have been implemented are send and respond with user data and link reset. The slave DNP driver will not respond until a link reset has been performed. The DNP master driver sends a Link Reset request when a Map Descriptor requests data from an un-reset node. The link resetting is performed on a node-node link.

Appendix A.6. App Layer Functionality in the Master

The App layer provides over 40 app layer functions, confirmations and responses and allows for handling of a huge number of data objects.

		1. Read
		2. Write
		3. Select
App	Layer	4. Operate
Functions		6. Direct Operate with no Ack (limited)
		8. Direct Freeze with no Ack (limited)
		129. Response
		130. Unsolicited. (Slave Driver can parse these messages.)
		The Slave indicates its internal state by appending internal indication bytes to the
		app layer header of each response. Thus it can report that it is faulty, corrupted or
		unable to process the request. If it can’t find a matching Map Descriptor it sets the
Internal		internal indication bit used to indicate that the data object parameters specified
		cannot be parsed.
Indications
		You can configure a Server node to respond with the internal indications bytes that
		are extracted from a Data Array allowing you to control them. For more
		information, refer to Error! Reference source not found..
App	Layer	The app layer contains a Qualifier Byte used to control indexing for data objects.
		The DNP 3.0 Driver only handles Qualifiers 00, 01, 07, 08, 17, 28. Qualifier 6 is
Qualifier		supported with limitations.
App	Layer	The DNP 3.0 (master) Driver never asks for an App Layer Confirmation. The DNP
		3.0 Slave Driver is capable of responding to an app layer request for confirmation
Confirmation		(to allow it to process an unsolicited message which may ask for confirmation.)

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