VINStrument

The VINStrument subsystem operates with the ARM and TRIGger subsystems to control the virtual instrument features of the HP E1429A/B. These features include the ability to use the Local bus and the VME (VXI data transfer) bus to obtain buffered measurement data from memory or real time measurement data directly from the analog to digital converter.

Local Bus transfers

There are two ways to transfer data over the Local bus:

Data can be transferred directly from the analog to digital converter(s) using the ARM and TRIGger subsystems in conjunction with the INITiate command. Everything proceeds exactly the same as if readings were going to HP E1429B internal memory, except in this case, readings are going to the Local bus as well as to internal memory. If the consumer on the Local Bus is unable to maintain the data transfer (sampling) rate, then the data going out over the Local bus is lost and an error is indicated.

The second method of transferring data over the Local bus is to empty the

HP E1429B internal memory after the measurements have occurred. This transfer will automatically proceed after the measurements are completed if the user has previously set the VINStrument:CONFigure:LBUS:MODE to APPend, GENerate, or INSert, and if VINStrument:CONFigure:LBUS:FEED is one of the "MEM:xxx" choices. If the measurement is aborted with the ABORt command, or if VINStrument:LBUS:MODE is OFF or PIPline during the measurement, then no automatic transfer is attempted. Instead, the VINStrument:CONFigure:LBUS:MEMory:INITiate command must be used to start the transfer after the MODE and FEED have been set to the desired values. When using this method, the ARM source is automatically set to IMMediate, and the trigger source is set to LBUS. This allows the receiving module(s) on the right to control the data transfer, and assures that transfers occur only when the receiving module is ready to receive data; thus no data will ever be lost. The trigger and arm sources are returned to their previous values with the next INITiate command.

VINStrument Subsystem

Command Reference 283

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Image 283
HP E1429A manual VINStrument, Local Bus transfers