Emerson 4620 Manuel D’Utilisation

The following figure illustrates an example configuration with four domains and three shelves. 

Any FRUs available in a shelf are represented as HPI resources together with Resource Data 
Records (RDRs) corresponding to that FRU. Whenever a FRU is added to or removed from a 
shelf, the corresponding HPI resource/RDR is added/removed from the HPI domain. 

In order to access an HPI domain, you must open a session via the HPI call 

saHpiSessionOpen()

 and provide as first parameter the domain ID of the corresponding HPI 

domain. How to obtain the domain ID is described later within this section about the multishelf 
HPI library. 

If you want to access several shelves, then you need to open several sessions simultaneously, 
one session for each HPI domain which represents a shelf. It is also possible to open several 
sessions for one HPI domain/shelf only as well. 

When the connection to a shelf is lost, all running HPI calls which access the corresponding 
domain return immediately with the error code SA_HPI_ERR_NO_RESPONSE. All open 
sessions for the affected domain are automatically closed by the multishelf library. In the 
meantime, the library tries to regain access to the shelf. As soon as the connection is 
reestablished, the domain is recreated and the application can open another session and 
access the domain again. Whenever a domain is created or removed, an HPI event from the 
HPI Communication State sensor is generated in the default domain (see 

 and 

). 

HPI events are handled domain wide. This means that HPI events from a shelf or FRUs in that 
shelf are only visible and can only be received within the session that corresponds to that 
domain.