HP 8901B Operation And Calibration Manual page 325

Model 8901B Operation
Special Functions
FUNCTIONS
All Special Functions prefixed 1 to 39
DESCRIPTION
General Information
Special functions enable extended use of the instrument beyond the control normally available from
dedicated front-panel keys. The special functions are best used after a thorough understanding of the
instrument is grasped.
Special functions are accessed via keyboard entry of the appropriate numeric code terminated by the
SPCL key. (Refer
to
"Procedures".) The codes comprise a prefix, decimal, and suffix. Special functions
are disabled in different ways, depending on the function. Refer to the following comprehensive table
for actions which clear or disable any special function. Special functions are grouped by their prefixes
into three categories as follows:
Prefix 0
Prefix 0 is the Direct Control Special Function intended for use in servicing the Modulation Analyzer
(discussed in detail in Section 8).
A l l
instrument error messages and safeguards are inactive. If the
Direct Control Special h c t i o n is entered inadvertently, press AUTOMATIC OPERATION.
Prefixes 1 to 39
Prefixes 1 to 39 are the User Special Functions that are used during normal instrument operation when
a special configuration, a special measurement, or special information is required. All error messages
and most safeguards remain in effect unless the operator disables them. These special functions are
described in the table in this instruction.
Prefixes 40 to 99
Prefixes
40
to 99 are the Service Special Functions used to assist in troubleshooting an instrument
fault (discussed in detail in Section 8). The functions available include special internal measurements,
software control, and special service tests and configurations. Most instrument safeguards are
relinquished.
If
a
Service Special F'unction is entered inadvertently, press AUTOMATIC OPERATION.
Repair personnel can gain arbitrary control of the instrument as an aid in troubleshooting.
Viewing Special Function States
In addition to completing the entry of special function codes, the SPCL key enables viewing of some
special function settings. The operator-requested settings of Special F'unctions prefixed 1 through 10
can be viewed by pressing the SPCL key once (following no numeric entry). This display is called
the Special Display. If some of these Special Functions are in automatic modes (generally the 0-suffix
setting), the actual instrument settings of these functions can be displayed by pressing the SPCL key a
second time while the Special Display is still active. This display is called the Special Special Display.
Both displays can be disabled by pressing any key except the Blue Key, LOCAL, or S (shift) key. (While
either display is active, pressing the SPCL key selects the other display.)
A summary of User Special Functions is provided at the end of this instruction. Also included in this
instruction are procedures for initiating special functions and for obtaining the Special Display and
the Special Special Display.
Special F'unctions 3-237