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Clock offsets and Delays

Field System and station time agreement

The fmset program can be used to confirm that the Field system time agrees with the station time. Open a terminal on pcfs[hb|ke|yg], and type


The Field System and Computer times should agree. Press the <esc> key to exit fmset.

Maser to GPS, Formatter to GPS delays and difference

Now check the maser-GPS and delay through the DBBC and Mark5 (Formatter minus GPS) with the




commands respectively which read the Agilent counters. Log these values in the checklist. They should bethe same to within 0.5 microsec. The Log Monitor should report the difference whuch should be less than +/- 0.5 us.

Issue the maserdelay and clkoff commands a few times to check that they aren't drifting. A drift in the formatter-GPS time is usually an indication of a DBBC problem, usually requiring a reconfig to fix.

If one or both counters are not responding to these commands, you will see an error message like this

ERROR sp   -4 GPIB Device time-out on response c2

To fix this, try re-setting the counters. In the Operator Input window, type


and try the maserdelay and clkoff commands again.

If the GPIB has been restarted (via the PDU internet power switch, or a power outage) a field system restart is probably required to re-establish communications with the counters connected to the GPIB. The ddif counter may be showing random large offsets, and/or changing rapidly. Restarting the field system should bring this counter back to a steady few microseconds.

/home/www/auscope/opswiki/data/attic/operations/documentation.clock_and_delay_check.1410481879.txt.gz · Last modified: 2014/09/12 00:31 by Warren Hankey