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operations:documentation.clock_and_delay_check [2014/09/12 00:36] Warren Hankey |
operations:documentation.clock_and_delay_check [2015/06/17 23:28] Lucia McCallum [Maser to GPS, Formatter to GPS delays and difference] |
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<code>fmset</code> | <code>fmset</code> | ||
The Field System and Computer times should agree. Press the <esc> key to exit fmset. | The Field System and Computer times should agree. Press the <esc> key to exit fmset. | ||
+ | |||
+ | If fmset if not successful (persistent clock differences), it might be wirth to (a) reboot the Mk5, (b) check the DBBC and/or reconfigure/reboot the DBBC. | ||
===== Maser to GPS, Formatter to GPS delays and difference ===== | ===== Maser to GPS, Formatter to GPS delays and difference ===== | ||
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If one or both counters are not responding to these commands, you will see an error message like this <code>ERROR sp -4 GPIB Device time-out on response c2</code> To fix this, try re-setting the counters. In the Operator Input window, type <code>counter</code> and try the ''maserdelay'' and ''clkoff'' commands again. | If one or both counters are not responding to these commands, you will see an error message like this <code>ERROR sp -4 GPIB Device time-out on response c2</code> To fix this, try re-setting the counters. In the Operator Input window, type <code>counter</code> and try the ''maserdelay'' and ''clkoff'' commands again. | ||
- | =====GPIB communication with counters trobleshooting ===== | + | |
- | 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. Symptomatic is the ddiff counter showing random large offsets and/or changing rapidly; <code>fmset</code> working OK, sync_error=0, but <code>counter</code>, <code>clkoff</code>,<code> maserdelay</code> commands not working. Restarting the field system should bring the ddiff counter back to a steady several microseconds. | + | **Be sure that mk5=dot? returns FHG_off before you run fmset. Sometimes if a power glitch occurs while the Mark5 is recording, it can get stuck. If FHG_on, end with disk_record=off and then run fmset again |
+ | |||
+ | During the observation, it is useful to monitor the delay difference on a plot. to do it, you can start a terminal on ops2 (or ops1hb at MtPleasant) and <code>cd /vlbobs/ivs/logs</code> Then start gnuplot: <code>gnuplot</code> You shall start and/or refresh the plot window for each station by hand each time you wish to see the plot: | ||
+ | |||
+ | <code> | ||
+ | set term 'wxt' 0 ; plot "hb_ddif.txt" | ||
+ | set term 'wxt' 1 ; plot "ke_ddif.txt" | ||
+ | set term 'wxt' 2 ; plot "yg_ddif.txt" | ||
+ | </code> | ||
+ | |||
+ | |||
+ | =====GPIB communication with Agilent counters ===== | ||
+ | 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. Symptomatic is ''fmset'' working OK, sync_error=0, but ''counter'', ''clkoff'','' maserdelay'' commands not working; the ddiff counter showing random large offsets and/or changing rapidly. Restarting the field system should bring the ddiff counter back to a steady several microseconds and enable GPIB comms. | ||