HP E8491A 2

Chapter 3
VXI Programming Using the IEEE 1394 Serial Bus ................................................	35
Using this Chapter ......................................................................................................	35
Programming Register-Based and Message-Based VXI Instruments .................	35
Opening Instrument Sessions ..............................................................................	35
Optimizing Programs ..........................................................................................	36
Block Data Transfers ....................................................................................	36
Block Transfers using HP VXIplug&play Drivers .......................................	37
Block Transfers using HP VISA ...................................................................	40
HP E8491A Triggering .......................................................................................	43
Using Triggers ..............................................................................................	43
Configuring the E8491A Trig In and Trig Out Ports ...................................	44
Triggering Example ......................................................................................	45
Trigger Pull Up .............................................................................................	47
Using HP E8491A Shared Memory ....................................................................	47
Locating E8491A Shared Memory ...............................................................	47
Example Programs ..............................................................................................	49
Storing Readings in Shared Memory - HP VISA Example ..........................	50
Storing Readings in Shared Memory - SICL Example ................................	54
Chapter 4
IEEE 1394 Fundamentals and
Interface Overview ......................................................................................................	57
Using this Chapter ......................................................................................................	57
IEEE 1394 Topology and Terminology ..............................................................	57
Features of the IEEE 1394 Bus .....................................................................	58
Optimizing the Configuration .......................................................................	59
IEEE 1394 Data Transfer Protocol ......................................................................	59
Asynchronous Data Transfers .......................................................................	60
Fair Arbitration Protocol ...............................................................................	60
VXI Data Transfers .......................................................................................	60
The Adaptec® AHA-8940 Host Adapter and Interface Cable ............................	61
The HP E8491A PC to VXI Interconnect ...........................................................	62
Using the HP E8491A with the HP E1406 Command Module ....................	64
The HP I_O Libraries ..........................................................................................	64
Appendix A
Specifications ................................................................................................................	65
Interface Characteristics ......................................................................................	65
VXI Characteristics .............................................................................................	65
General ..........................................................................................................	65
CLK 10 .........................................................................................................	66
External Trigger Input ..................................................................................	66
External Trigger Output ................................................................................	66
Trigger Delays ..............................................................................................	67
Cooling .........................................................................................................	67
Power Supply Loading .................................................................................	67

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