User's Manual

Rev B
7
new environment (e.g., frequency scan or signal measurement) in which keys may be reassigned
and functions redefined. Navigation is guided by interactive menus and the
ESCape key.
PROM initialization
Operating system software is contained in one (SRX_400 ‘A’ models) or two (earlier models)
programmable read only memories (PROMs). The SRX_400 can run a variety of different
software versions which are specialized for particular applications. Although some options must
be factory installed (for extended memory, etc.), some version changes and most regular
upgrades may be made in the field. The general procedure for installing and initializing PROMs,
using the New_Prom routine, is given in Appendix C.
Although it should normally not be required, the New_Prom routine can be used as a general
low-level software reset in the event of catastrophic misbehaviour. Note that, unlike the
hardware reset (pressing SHIFT and ESC keys together), New_Prom will typically reset system
status variables (like communication port settings) and purge frequency tables and other data. If
you do need to use it, please report the circumstances to Lotek’s customer support department.
Warning: Changes or modifications not expressly approved by Lotek Engineering could void the
user's authority to operate the equipment.
The Keys and their Functions
All keys except
SHIFT have dual markings. The upper markings (above the line) represent
SHIFTed functions or commands. The lower markings include some commands but mostly they
are reserved for the numeric digits 0 to 9 and the decimal point (.). Any key can therefore be
referred to by two names, depending on which key function is being selected. This convention is
used in the discussion below.
Numeric values are normally entered as a specific number of digits, including leading zeros
as necessary.
The
SHIFT key selects the functions indicated on the upper half of the keys. When
SHIFT is activated the ^ symbol appears in the lower right corner of the display.
When the batteries are low, the ^ symbol is replaced by a small picture of a battery.
The
SHIFT key is also used as a "continue" or "confirm" operator in some routines (SEARCH mode
and RS232 configuration in
COMM) and to return from HELP.
The
DOWNARROW key is used to decrement the value of a selected variable
(normally frequency, gain or scan time) by a selected amount. The variable is
selected by whichever of the
SET G, SET F, or SET SCAN keys were most recently
activated. The decrement amount is the last value entered using the
SET ∆ function. In the SCAN
mode (see below), the arrow keys may also be used for manual scanning, frequency table editing
and control of signal window size. The
DOWNARROW also provides a line editing function
(backspace) for real number entry (e.g., to calibration tables).
The
SET G key activates the set_gain function, which first issues a prompt
SHIFT
SET G