Setting the VME bus Data Source

The source of the readings transferred over the VME bus is set with the command:

VINStrument[:CONFigure]:VME:FEED <source >

The <source > parameters are given below. Sources beginning with "MEMory: " are the post measurement sources (modes), sources beginning with "CONVerter: " are the real time sources (modes).

"MEMory:CHANnel1": Channel 1 memory is the data source for the VME bus. One 16-bit reading is returned.

"MEMory:CHANnel2": Channel 2 memory is the data source for the VME bus. One 16-bit reading is returned.

"MEMory:BOTH": Both channels of memory are the data source for the VME bus. In this mode, channel 1 will be output the first time the data register is accessed, channel 2 is output the second time the data register is accessed. One 16-bit reading is returned with each access.

"MEMory:BOTH32": Both channels of memory are the data source for the VME bus. In this mode, accessing the data register returns a 32-bit number where the high order 16 bits are the channel 2 reading and the low order 16 bits are the channel 1 reading (see Figure 3-11).

"CONVerter:CHANnel1": The channel 1 A/D converter is the data source for the VME bus. One 16-bit reading is returned.

"CONVerter:CHANnel2": The channel 2 A/D converter is the data source for the VME bus. One 16-bit reading is returned.

"CONVerter:BOTH": Accessing the data register triggers both A/D converters at the same time, and one 16-bit reading (channel 1) is returned. Accessing the data register a second time returns the second 16-bit reading (channel 2), but does not trigger the A/Ds.

"CONVerter:BOTH32": Accessing the data register triggers both A/D converters at the same time, and one 32-bit number is returned. The high order 16 bits are the channel 2 reading, and the low order 16 bits are the channel 1 reading (Figure 3-11).

If it is necessary to identify readings from channel 1 and channel 2, a data label can be assigned to the readings as described in the section "Assigning a Data Label" on page 130.

152 Understanding the HP E1429 Digitizer

Chapter 3

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HP E1429A manual Setting the VME bus Data Source