VXI-11(网络设备)协议学习

›VXI-11 Concept
VMEbus Extensions for Instrumentation TCP/IP Instrument Protocol Specification VXI-11, Revision 1.0 is authored by the VXIbus Consortium, Inc. and its sponsor members:
–GenRad, Inc.
–Hewlett-Packard Co.
–National Instruments, Corp.
–Racal Instruments, Inc.
–Tektronix, Inc.
–Wavetek, Inc.
VXI-11 Family
VXI-11.1TCP/IP-VXIbus Interface Specification
VXI-11.2TCP/IP-IEEE 488.1 Interface Specification
VXI-11.3TCP/IP-IEEE 488.2 Instrument Interface Specification
 
Network Instrument Protocol
The network instrument protocol uses the ONC remote procedure call (RPC) model. Conceptually, this model allows one application (typically called the client) to call procedures in a remote application (typically called the server) as if the remote procedures were local.
This specification uses ONC/RPC for defining the network instrumentmessages which are passed over the network, but does not require that these RPCs be provided as the application interface. The ONC/RPC interface may,  however, be used by a device designer as a matter of convenience.
 
Network Instrument Protocol
 
Protocol Foundations
The network instrument protocol is an application layer protocol designed for controller to device
communication using a paradigm similar to communication with IEEE 488 devices.
The networkinstrument protocol is built on an industry-standard protocol stack, allowing instrumentation and controllers to communicate over existing networks.
The following sections work from the bottom of the protocol stack upward, describing the protocol stack requirements of controllers or devices which implement the network instrumentprotocol.
 
Protocol Stack Summary
 
Network Instrument Messages (RPCs)
 
Example:create_link
The create_link RPC creates a new link. This link is identified on subsequent RPCs by the lidreturned
from the network instrument server.
struct Create_LinkParms {
long clientId; /* implementation specific value.*/
bool lockDevice; /* attempt to lock the device */
unsigned long lock_timeout; /* time to wait on a lock */
string device<>; /* name of device */
};
struct Create_LinkResp {
Device_ErrorCode error;
Device_Link lid;
unsigned short abortPort; /* for the abort RPC */
unsigned long maxRecvSize; /* specifies max data size in bytes
device will accept on a write */
};
Create_LinkResp create_link(Create_LinkParms) = 10;
RULE B.6.3:
To successfully complete a create_linkRPC, a network instrument server SHALL:
1. If lockDevice is set to true, acquire the lock for the device.
2. Return in lid a link identifier to be used with future calls. The value of lid SHALL be unique for
all currently active links within a network instrument server.
3. Return in maxRecvSize the size of the largest dataparameter the network instrument server can
accept in a device_write RPC. This value SHALLbe at least 1024.
4. Return in asyncPort the port number for asynchronous RPCs. See device_abort.
5. Return with error set to 0, no error, to indicate successful completion.
The device parameter is a string which identifies the device for communications. See the document(s)
referred to in section A.6, Related Documents, for definitions of this string.
 
 
Demo
 
Port Map Register
 
Port Map look up (GetPort Call)
Port Map look up (GetPort Reply)
Create Link Request
Create Link Response
 
Device Write Request
 
Device Write Response
 
Device Read Request
 
Device Read Response
 
 
 

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