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User name Eric Voutier
Log entry time 04:51:25 on October11,2000
Entry number 50061
This entry is a followup to: 50054
keyword=Target problem/parameters
-# 1st the target loss...
At the shift change over, it was noticed that the target was constantly beeping
yellow on two temperature sensors forbidding us to reach the target 70uA. After
checking with Kathy that all important parameters of the target were okay as well
as those from the refrigerator and the ESR, we conclude that these sensors
(L1_CT_HX_in_R and L1_AT_HX_in_R) known to be inaccurate were
meaningless. Then we start increasing the current and the pressure rapidly reaches
about 240 psi. We conclude that something was wrong with the IOC and decide to
reboot it while the beam was off.
When rebooting IOC the target vents. The understanding of the vent is explained
in Jo's entry 50054.
It seems that the diagnostic which led us to reboot the IOC was okay (that needs to
be confirmed by Kathy's tracking of the event): the temperature controller was not really working and CT97/CT96 were always reading constant values; when increa-
sing the current, part of the heat excess was not extracted from the loop and the
pressure goes up.
The error is after the IOC reboot when going back too early in PID mode: the
combination of a slow communication and a set of "rainbow" alarms "distract" me from the TV screen of the temperature readings and... the target vents!
-# The target parameters at 70uA after recovery are :
PT267 = 232.1 psi
CT97 = 5.80 K
CT96 = 5.79 K
Fan = 60 Hz