Introduction
E2050 Software/Firmware Architecture
Using Application Software
Establishing a Network Connection
This section summarizes how the software on a client computer system works with the E2050 LAN/GPIB Gateway to complete I/O application operations on attached GPIB instruments. For more information on how to use your software with the Gateway, see the applicable software documentation as listed in “Related Software Documentation”.
Before trying to perform an I/O application operation on the Gateway’s GPIB interface and the GPIB bus, the LAN client software in the client computer system establishes a network connection to the LAN server (the Gateway). Once the client establishes a connection, the client can begin to send I/O requests to the Gateway.
Maximum Client Connections
The Gateway (LAN server) can have multiple clients connected and being serviced at any given time. The maximum number of concurrent client connections depends on memory usage in the Gateway, including the number of clients and the number of current sessions running on those clients. However, at least 8, but not more than 15, client connections can be running concurrently. Thus, if the maximum number of client connections to the Gateway has not been exceeded, the connection is allowed to occur.
I/O Application Operation
Using Locks
Although several instruments can be connected to the Gateway’s GPIB bus, only one I/O application operation can occur on the GPIB bus at any given time. Therefore, once a client’s request begins to execute on the GPIB, all other client requests for operations on the GPIB must wait until the current client request completes. Client requests are serviced in a first come, first served manner, unless they are prohibited by interface or device locks.
If a client has a sequence of I/O application operations to perform that should not be preempted, the client should obtain a lock on the Gateway’s GPIB interface or device. Once the client’s sequence has completed, it should release its lock, allowing other clients access.
Closing a Network Connection
When a client closes a connection, the Gateway frees up the resources allocated to that client, including any locks, pending I/O requests, memory usage, etc. Abnormal termination (for example, the network and/or client goes down) is discussed in Chapter 5.
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