The Display Window
- The B3 microcomputer is connected to the terminal server
in the receiver cabin. This permits remote monitoring and control of the
receiver.
Most commonly, the TSS will use this feature to bring up the
status screen on a window of his/her VAX operating terminal. Without
recourse to the ttrecon utility, it is not at present possible to
have more than one monitoring window open at once.
In general, to open the B3 status window, login to MWTTEL and
open a DECterm Applications window. Alternatively, can run the status window
on a separate VT terminal set up for the purpose, which is currently
the way things are configured. At the $ prompt type
set term/device=vt100/perm lta150
set host/dte lta150
If the connection succeeds, it will do so immediately to the first of
these commands. To refresh the display type Q. To get the PF keys (see
below) to work Choose Options from the menu bar at the window top,
then General and select VT100, APPLY and OK.
To exit from the B3 screen, type
cntrl
The display consists of four screens showing schematic diagrams
that represent the main components of the receiver and the demand
values of the controllable parameters associated with each component.
It is especially important to check the Display after tuning the
receiver as any improperly set parameters will be displayed in reverse
video mode beside or underneath the correct value.
The Display screens also contain menus that permit changing the demand
settings of each of the remotely controlled receiver components. This
Display terminal talks directly to the microcomputer and bypasses the
normal VAX control procedure. To change a particular parameter, the
appropriate menu for that component is selected by returning to the
Executive Menu from a lower menu through a series of (Q)uit commands.
Note:
The
Executive Menu differs from the others in that e(X)it, not (Q)uit is
displayed as the command needed to exit from the Display task. You should
not e(X)it from the Display task unless you want to "fly blind"
with B3, not usually a very good idea.
Once in the Executive
menu, respond to the menu options to select the component with the
parameter to be changed. Once a component is selected, you will be prompted
to enter the new value for its parameter.
Under normal use, it should not be
necessary to use the Display terminal to enter parameter values.
The Four Display Screens
- There are four schematic display screens selected by pressing
the PF1, PF2, PF3 and PF4 keys.
The PF1 Display - the LO Window
This window shows the LO chain including the Gunn oscillator, the Modulator,
the Half-wave Plate and the Multiplier. Note that if you wish to use the
menu to change the Gunn tune or backshort positions to known values you must
toggle the (M)icrometer from (H)old to (A)djust mode
The PF2 Display - the Optics Window
This window shows the chopper positions and the dual beam interferometer.
It is useful for watching the progress of a calibration sequence and to
check that the DBI is not in motion (as it might be after a reboot procedure).
The Display menu can be used to switch remotely between the different
loads.
The PF3 Display - the Mixer/IF Window
This window shows a schematic of the two mixers side-by-side with the
settings of the backshorts, the bias voltages and junction currents
displayed between the mixer schematics. Also shown are the IF power levels
and the attenuator settings. Note: These IF
levels may appear "Hi" or "Lo" immediately following a tuning. They
do not affect the tuning itself and will be set correctly during the
first calibration procedure.
The PF4 Display - Miscellaneous
This window contains a display of miscellaneous data including the
temperatures of the radiation shields, the cold station and the status
of the various power supplies.
Note: When the receiver is on-line the HEMT amplifiers'
status values are not read and will appear uniformly as zeroes. These
quantities are only monitored and correctly displayed when the receiver
is on standby or if the LO is out of lock. The correct values may be read
at all times on the
electronics rack in the receiver cabin. Conversely, the shield and
cold station temperatures displayed on the electronics rack are incorrect
at present. The PF4 values for these temperatures are correct.
-
The VAX Receiver Status Window
- The receiver status may also be monitored through the VAX. There are
a number of key status parameters that are continuously monitored and
are flagged in the event of receiver failure and written to a status window
that can be continuously displayed. A window may be opened on the
TO's terminal by typing
ICL> put_screen rxb
To bring up the status screen on another server (e.g. iiwi), login to the
server and type
xhost+
then on the TO's terminal
put_screen rxb3 iiwi
This receiver status screen may also be displayed by choosing the s1 screen
at the TO's terminal, but this will temporarily overwrite the s0 (telescope)
screen.
