Instrument Logical Addresses

Instrument Secondary Addresses

Instruments are identified by a logical address which directly relates to its GPIB secondary address. Instruments come from the factory with a preset logical address. You can change the factory setting during installation (see the "Agilent 75000 Series B Installation and Getting Started Guide" for instructions).

A single-module instrument must have its logical address set to an integer multiple of 8 (0, 8, 16, 24, ... 240). In a multiple-module instrument, only one of the modules has a logical address that is an integer multiple of 8. The other modules in the multiple-module instrument must have consecutive logical addresses. For example, in a Scanning Voltmeter, if the voltmeter module has a logical address of 16, the other modules in that instrument must have logical addresses of 17, 18, 19 and so on. The same applies to the System Instrument who’s logical address fixed at 0. An E1324A plug-in serial interface controlled by the System Instrument would be set to logical address 1. A second E1324A would be set to logical address 2 and so on.

An instrument’s GPIB secondary address is simply the logical address divided by 8 (for a multiple-module instrument, the lowest logical address divided by 8). For example, an instrument with a logical address of 16 has a secondary address of 02. The secondary address allows access to a particular instrument when programming via GPIB. (The System Instrument’s secondary address is 00 and is the only address that cannot be changed).

Unassigned Modules An unassigned module in an E1300B/E1301B Mainframe is one that does not have a logical address that is a multiple of 8 (8, 16, 24...240) and is not part of a Scanning Voltmeter or Switchbox configuration. You can only program these modules at the register level using the VXI:WRITE and VXI:READ? commands (see Chapter 5 of this manual for more information on these commands).

Introductory

Programming

Examples

This section shows how to send SCPI and Common Commands to the mainframe’s System Instrument and how to read data back. The following assumes that you send the commands or read the data over GPIB. To send SCPI commands or to read data, specify the:

Computer’s GPIB interface address

Mainframe’s GPIB primary address

Instrument’s GPIB secondary address

SCPI command string or Common Command

For instruments in the mainframe, the primary address is the same as the mainframe address (i.e., the factory setting is 09). The instrument’s secondary address is simply the logical address divided by 8 (e.g., logical addresses of 8, 16, 24, or 32, result in secondary addresses of 01, 02, 03, or 04, respectively).

1-4 Getting Started

Page 18
Image 18
Agilent Technologies E1301B Introductory Programming Examples, Instrument Logical Addresses Instrument Secondary Addresses