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IVS Monitor

Monitoring IVS Experiments

During an experiment there are several things that should be checked in order to make sure that the data is being correctly recorded. These maintenance items are provided on an IVS checklist which should be located on a clipboard near the Hobart computer or the clipboard rack just left of the receiver control laptop.

Periodically check all the items on the checklist each hour, and complete the check list once every four hours.

Checking Clocks

Check to make sure that all the clocks:

  • Drive PC,
  • Formatter,
  • Decoder and
  • the AT Maser

are synchronized to the GPS clock located above the Hobart computer. There is a 1 PPS pulse town switch located on rack one which can help check that the clock are synchronised.

Check that the clkoff procedure is being correctly logged in the field system, this can be done by looking at the most recent output in the Field System Log window, or by issuing the command

clkoff

in the Operator input window on the Hobart computer.

Checking the VC power levels

The Mark5 rack, (two racks to the left of the Hobart computer) contains VC units, each of these units has a rotary switch allowing you to check the frequency (freq), the Upperside band power (USB) and the Lowerside band power (LSB). To check the VC power levels, make sure that all the units being used in the experiment are set to display the USB power (most of them will be already set to this display mode)

The power levels should still be between 0.1 and 1.

Checking the VC phase stability

There should be a coax cable plugged into a USB coax ports on one of the VC units, check that the phase tone is stable plugging this cable into each VC’s USB output and check to see if the tone is visible by looking at the oscilloscope (one rack to the right of Hobart, near the top). If you see the tone (sinewave) then the tone is present. Note that not all VC’s are used in every experiment. Unused VC will not show a tone. If a tone is not present in a VC unit that IS being used in the experiment please contact the telescope manager.

Disk position

In order to make sure that the correct amount of data has been recorded to the Mark5, you will need to check that the data volume is approximately the correct size. To check this, issue the command

disk_pos

in the operator input window in Hobart and check that the number of bytes which will be listed in the log windows, matches the expected number of GB listed in the schedule at the given time. The observing schedule will be located on the clipboard below the checklist.

Checking the system temperature

One of the windows located on Hobart will be the System Temperature window, make sure that the listed system temperature are between 50 and 70 K.

Checking the logging procedure

During the experiment the weather, clkoff and cable values will be logged, scroll back through the log and check to see that these commands have been issued and that the results displayed are reasonable.

The commands to look for are:

wth
clkoff
cable

If you cannot find one of these command in the log simple issue the command in the operator input window and check that the output is reasonable.

The wth command outputs a list of numbers, Temperature, pressure and humidity.

Cable and clkoff given time results in microseconds, the outputs should approximately match the values on the timing units located below the Hobart computer.

Logging the weather

In the operator output window enter the following note: (don’t forget the quote symbol)

“Weather: (cloudcover)% Cloud cover, Wind (Speed) km/h (direction).

Where (cloud cover) is you best guess at the percentage of sky which is covered by cloud, estimate by walking outside and having a good look around.

The wind speed and direction can be read from the two dials located on the top of the drive panel.

Checking Stalm

Check that the station alarm window is displayed on Hobart, it’s a grey windows which outputs all the alarms and controls the alarm tone. If the station alarm is not running start it by left clicking the background, moving the mouse to Field System, and then clicking Stalm.

Checking the Field System Monitor

The field system monitor sounds an audiable alarm if it detects that the field system has crashed. You can check that the field system monitor is running by looking for the green monitor window on Smerd, the windows should be listing all the times that it has checked the field system and it should update once every 61 seconds. If the field system monitor isn’t running, select Fsmon from the blue launch panel at the top of smerd’s display. A green window should appear in the lower left corner of the screen. You’ll need to log into this window with the oper account:

Username: oper
password:

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Page last modified on December 01, 2010, at 11:58 PM