Giga-tronics 8650B Series, Руководство по эксплуатации

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Remote Operation
Publication 31470-001, Rev C, November 2, 2017 3-67
3.3 IEEE 488.2 Interface Command Codes
3.3.1 Command Syntax
The elements of the 8650B interface commands are introduced in this section. Because some commands are
included only for compatibility with earlier models, there are some variations in syntax from one command to
another, which must be carefully observed.
3.3.1.1 Function Codes
An interface command includes a function code to indicate the nature and purpose of the command. Some
commands contain a function code and nothing else. For example, the function AP, which causes the 8650B to
measure power using the A sensor, stands alone as a command. Commands consisting only of a function code
are referred to in this manual as
simple
commands. However, most commands consist of a function code
combined with other elements.
The CH
n
EN (where
n
= display line number) command must precede commands for setting units and resolution
of power measurement and for setting relative mode, limits, min/max, and statistics. All subsequent commands
will apply to the same display line number.
Function codes are listed alphabetically in the Command Code Sets in this section.
3.3.1.2 Prefixes
Some commands must begin with a prefix that identifies the sensor to which the command applies. For
example, function code ZE (which causes a sensor to be zeroed) must be combined with a prefix to specify which
sensor is zero’ed. The full command is either AE ZE (for sensor A) or BE ZE (for sensor B).
Many of the commands described in this chapter require an AE or BE prefix, which specifies the sensor that will
be affected by the command. When the 8650B receives a command containing a sensor specific prefix, it
assumes that all subsequent commands refer to the same sensor until a command is received to specify the
other sensor. Therefore, if a command prefixed by AE is received, subsequent commands can omit the prefix
provided that they are intended for Sensor A.
It does no harm to include the prefix even when it is not required; some users may find that the most
convenient approach is to include the prefix in all applicable commands.
3.3.1.3 Variables.
Some commands must include one or more variables to specify quantities or options for the command. For
example, the function code ANALOG (used in commands to configure the analog output) is combined with
several variables to specify different aspects of the analog output. In the command:
ANALOG LOG -80.0, 20.0, 0.0, 10.0
the variables are interpreted as follows:
LOG Specifies that power is to be measured in logarithmic units (that is, dB or dBm).
-80.0 Specifies that the low end of the analog output voltage range represents -80 dBm in.
+20.0 Specifies that the high end of the analog output voltage range repr20 dBm in.
0.00 Specifies that the low end of the analog output range is 0 volts.