FieldServer FS-8700-73 - Manual (Page 28)

FS-8700-73 BACnet MSTP Driver Manual Page 28 of 48
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Appendix A.8. Factors Determining the Reliability Property
The Reliability Property of a BACnet object in a Server configuration is determined as follows:
For Multistate Inputs, Outputs and Values, the Reliability property is set to MULTI_STATE_FAULT (9) when the
Present_Value of the object corresponds to an entry in the Fault_Values property of the object, as
configured by the State_Text table in the configuration file.
For all object types, the Reliability property is set to COMMUNICATIONS_FAILURE (12) when the responsible
Server Node is offline.
When neither Condition 1 nor Condition 2 is met, the Reliability property is set to NO_FAULT_DETECTED (0)
Appendix A.9. Specifying ReadPropertyMultiple and WritePropertyMultiple Transactions using Linked
Map Descriptors
The ReadPropertyMultiple (RPM) and WritePropertyMultiple (WPM) BACnet services allow many objects and
attributes to be read and written in a single transaction. Since FieldServer Map Descriptors can only refer to a
single object type and address range, a RPM or WPM transaction can be constructed by linking multiple Map
Descriptors. This is done using the following components:
an active read or write Map Descriptor that defines the behavior of the RPM or WPM transaction via:
Function, e.g. Rdbc, Arcs, Wrbc, Wrbx
 Scan_interval

Timeout

Length

any number of Linked Map Descriptors specifying additional objects and data array locations to be
included in the transaction. Each Linked Map Descriptor is specified with the following settings:

Linked_Map_Descriptor - this is a reference by name to the active Map Descriptor described above, which
controls the transaction

Function - Passive_Client

Length
The number of Linked Map Descriptors is limited by the maximum message length allowed for the BACnet driver in
question. When too many Map Descriptors have been linked a SEGMENTATION_NOT_SUPPORTED error message
will be generated on the first poll attempt. This message will recommend splitting the RPM or WPM transaction
into multiple transactions, e.g.
DRV->BACnet : Linked Map Desc. "CMD_WPM" is too long.
Message Segmentation not supported.
Please split the transaction into multiple Linked Map Descriptors.