Checklist Parameter Descriptions
Note: In case of a power outage, you cannot assume that anything is safe! Use the pre-observation checklist.
Below is an explanation of the current list of items to check during an observation:
- Antenna: drives OK
Check the antenna status display in the system monitor window for the antenna. If Drive Status is green then all is well.
- Antenna: Time OK (i.e. SNTP server OK)
Check the Controller Clock status display in the system monitor window for the antenna. If it's green and “OK” then the controller knows the time. If not, the antenna probably doesn't know where its pointing, there's a problem. Check the HMI display on the time[hb|ke|yg] VNC session for more information. If HMI isn't running or you want to restart it here are some notes on Starting HMI.
- Antenna: on source and tracking
In eRemoteControl, type
onsourceand check the antenna is tracking, which it should be provided a new source command hasn't recently been issued.
- Data: LO Locked
In the System monitor, in the RF section, check that the LO Status is Locked. If not, no valid data will be recorded.
- Data: Autocorrelations OK
At the end of every scan, the postob procedure will run a script to extract some Mark5 data and plot the autocorrections. They can be viewed shortly after on the Autocorrelation web page. This page is updated every minute and also tells you how long ago the data were taken. If it's been too long, check the PCFS VNC to see if they're being updated locally. Good data should contain quite flat bandpasses and zero phase. See autocorrelation spectra plots for an example and what problems to look out for. If there's a problem, the DBBC may need reconfiguring.
- Time: delays OK, stable and within 1us (clkoff, maserdelay)
In the eRemoteControl, issue the commands
maserdelay. These values should be within 1 microsecond of each other and stable (i.e. similar results if you issue the commands again). The monitoring software will calculate the difference for you and should ring an alarm if the difference is not acceptable. Typical values for the three sites are
- Hb -0.6 ± 0.1
- Ke -0.15
- Yg -0.3 |
- Time: Maser status OK
Check the “Standard VCH-1005A Manager” display on the Windows PC (to view it, start a VNC session via the Applications menu to time[hb|ke|yg]). Green numbers are good, red are bad. Here's an example of how it should look:
Report any red numbers to Brett ASAP. if you see mention of 'Battery', the maser has lost mains power and is running on it's UPS. If so, tell Brett immediately.
- Mark5: mk5=mode? correct
Check mode with this command in the oprin:
mk5=mode?. The result should be, ( where the last number represents the number of disk modules loaded, either 1 or 2 ),
/mk5/!mode? 0 : ext : 0xffffffff : 2 : 2 ;for special 2-bit R1/R4 experiments,
/mk5/!mode? 0 : ext : 0x55555555 : 2 : 2 ;for most R1 and R4 experiments,
/mk5/!mode? 0 : ext : 0x55555555 : 4 : 2 ;for OHG, APSG, T2 and some CRF observations
/mk5/!mode? 0 : ext : 0xffffffff: 1 : 2 ;for AUA, AUM and most AOV experiments
More information may be found on the Mark5 mode page.
- Mark5: mk5=dot? response nominal
This is a check of the Mark5 decoder time. Check the time offset in the formatter with this command in econtrol:
mk5=dot?. Make sure it reports a small offset (~<10ms) as the final value, that
FHG_offdepending on whether it is currently recording or not.
- Mark5: disk_pos OK
Also see disk_pos.py. The command
disk_posin eRemoteControl should report three values - the current number of btyes recorded, bytes at start of previous scan and bytes at start of current scan. If not currently recording, the first and third values should agree. It is normal for
disk_posto lag its expected value slightly, but the discrepancy should be< 1%. The Log Monitor also reports disk usage. Compare amount of bytes recorded with that listed in the summary file (e.g. r4000hb.sum). Snap-file summary is located in /vlbobs/ivs/sched/, and according to current practice, should be open in the favourite text editor on the screen (for all monitored antennas) (don't forget to ssh to ops8 if you're not already there). Feel free to edit and add your comments.
- If the recording lags the summary file significantly (e.g more than 1% and/or several 10s of gigabytes and growing), it might be an rfpic issue wheret he recording does not start in time because it is waiting for the report from Monica. In this case you shall restart the Rxmon, at it is described in the Other things to watch out for: "rfpic" problem
- Meteorology: Weather (wth) being logged
Look through recent messages in the field system log for output from the
wthcommand, which will look like this:\\/#wx#/16.1,1007.9,58.6
- If the weather is either not updating, or not returning anything see this page
- Meteorology: Sky conditions logged
Make a note in the entry box of present weather conditions like cloud cover and wind e.g. “weather 50% cloud, light winds”.
- Tsys: S-band Tsys OK
Check recent output from a systemp12 command (don't execute it unless the Mark5 is NOT recording) to see if the S-band Tsys is within the expected range (an indication will be given in brackets, but 80 to 100 K is typical). The monit3 window shows the most recent values and here is how to interpret them. Note that at Ke, continuous Tsys measurements are made during scans and the monit3 window updates every 30s with these values. However you can obtain a Tsys value at any time at ke with the systemp12 command (see also these notes on Continuous Calibration). Make a note in the log if it is outside this range. If it persists, or the values vary wildly, there may be a problem.
- Tsys: X-band Tsys OK
Check recent output from a systemp12 command (don't execute it unless the Mark5 is NOT recording) to see if the X-band Tsys is within the expected range (an indication will be given in brackets, but 80 to 100 K is typical). The monit3 window shows the most recent values and here is how to interpret them. Note that at Ke, continuous Tsys measurements are made during scans and the monit3 window updates every 30s with these values. However you can obtain a Tsys value at any time at ke with the systemp12 command (see also these notes on Continuous Calibration). Make a note in the log if it is outside this range. If it persists, or the values vary wildly, there may be a problem.
- Log Monitor audio check button sounds audible beep. Make sure you can hear the alarms
- System: Any problems or concerns logged
If there are any other issues or unusual behaviour, report it in the log by typing in the comments box at the end of the dialog.