IVS Experiments
- Setting Up
- DBBC configuration

IVS Experiments

Setting Up

Mark5B

As oper@mk5ya, first check if the dimino program is running (ps -ef | grep dim). If not, start it with “dimino -m0&”. While your at the prompt, check that the ntp time is correct by running “ntpq -np” (for a non-interactive session). Alternatively, run ntpq and then issue the “peers” command. The offset and delay to tac32ho should be small (less than ~5 milliseconds). If it is not, then you will need to resynch the machine to the NTP server. As root, issue the commands

/etc/init.d/ntp stop
ntpdate cnsshb
/etc/init.d/ntp stop

After entering these commands, check the ntp status again. Once the NTP time is ok, you will need to run “fmset” on pcfshb, set the time (with “.”) and then sync the formatter (“s”, followed by “y”). Exit from fmset as soon as you have finished.

It's worthwhile making a test recording using the mark5b. To do this you can either use tstdimino on mk5ya or the fs. The instructions below are for the fs but to use them in tstdimino, omit the leading “mk5=”.

mk5=mode=ext:0x55555555:2 (For VSI recording, 1-bit sampling, 8 MHz BW) mk5=dot? (Check that the times reported are correct, that FHG_off and syncerr_eq_0) and that the final number is less than ~5 ms)
mk5=record=on
mk5=dot? (As before, but it should say FHG_on)
mk5=record=off
mk5=scan_check? (Check the last numbers are the correct date at the start of the scan, duration, the data rate (should be 256 for this mode) and 0 at the end for no problems)

If all seems ok, delete the recording from the disk using

mk5=protect=off
mk5=reset=erase

Make sure there are no other experiments on the module or you will erase those too with this command!!

Running the Schedule

Start the schedule with “schedule=r4447hb,#1” as usual. During the experiment, the following checks can be made.

onsource - Onsource reporting does not work reliably at the moment. Instead check the HMI controller for the current Az, El and the reported errors. The Az & El of the source at the start of the scan are listed in the printed snap file summary.

Clocks

Run “/usr/bin/xterm -name monit2 -e /usr2/fs/bin/monit2” on pcfshb to check pcfs time.
Check SNTP Server OK in the HMI
Run clkoff to check formatter-GPS time offset

Rx/IF system - Run systemp12 to check system temperature. The reported values should be ~25 CAL units for S-band (only one channel has the appropriate filter and will give consistent values) and 12-13 CALs for X-band. When scaled to Kelvin, expect values of ~85-90 K.

Mark5B

disk_pos 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.
decoder time - Check time offset in the formatter with “mk5=dot?” and check that it reports a small offset as the final value, than syncerr_eq_0 and that FHG_on or FHG_off depending on whether it is currently recording or not.
Check mode with “mk5=mode?”. The result should be “/mk5/!mode? 0 : ext : 0x55555555 : 2 : 2 ”; (where the last number is either 1 or 2, the number of disk modules loaded

Weather Conditions - wth as usual. Also log conditions as per 26m

End of experiment - The “source=stow” command does not currently work so please stow the dish using the HMI interface and the “Stow” button.

To run the status monitor, enter this command at the pcfshb prompt

/usr/bin/xterm -name monit2 -e /usr2/fs/bin/monit2

Common problems

clkoff reading is drifting or far from the maser-GPS offset - This usually is caused by the DBBC. First, go around the back of rack 14 and move the cable from the DOTMON output of the Mark5B to the “1 PPS Mon” output of the DBBC (left hand side, sixth SMA from the top). If the same offset is seen on the counter, then the problem in in the DBBC. A temporary fix can be achieved with pps_sync in DBBC Control but this did not reliably fix the problem on 13/10/10. Instead, try reconfiguring the DBBC with reconf - this will take ~two minutes in total and you will need to re-issue the dbbcifa=… commands, and resynch the mark5B with fmset.r at the prompt, check that the ntp time is correct by running “ntpq”, and then issuing the “peers” command. The offset and delay to tac32ho should be small (less than ~5 milliseconds). If it is not, then the best thing to do is to run “fmset” on pcfshb, set the time (with “.”) and then sync the formatter (“s”, followed by “y”). Exit from fmset as soon as you have finished.