StatusStatus
100%100%
30%30%
100%100%
STATUS REPORT onSTATUS REPORT onElectromagnetical Perturbations on the Electromagnetical Perturbations on the Hardwired Safety AlarmsHardwired Safety Alarms
The investigations to understand the causes The investigations to understand the causes of hardwired alarm level 3 induced by of hardwired alarm level 3 induced by electromagnetic perturbations in electromagnetic perturbations in correspondence of the 18kV power breakdown correspondence of the 18kV power breakdown indicated two actions:indicated two actions:
Implementation of a low-pass filter on the input of the hardware-triggering unit,
Revision of the shielding and grounding of the existing hardwired network.
Implementation of a data logger on the main hardwired links.
StatusStatus
OKOK
OKOK
OKOK
OKOK
STATUS REPORT onSTATUS REPORT onElectromagnetical Perturbations on the Electromagnetical Perturbations on the Hardwired Safety AlarmsHardwired Safety Alarms
Implementation of a low-pass Implementation of a low-pass filter on the input of the filter on the input of the hardware-triggering unithardware-triggering unit
Designed using MATLAB and test field measurements
Installed, tested and in operation since May 2001
NO spurious alarms due to Electromagnetical Perturbations have been recorded
Inspected by TIS and their EMC consultant
Triggering unit’s equivalent circuit: with and without the input filter.
Comparison between the experimental data and the simulations
Note that the input voltage of
the triggering units follows
closely the perturbation in
case A
Note that the presence of the
input filter avoids that short-
lived events trigger alarm
while long-lived events trigger
alarm
StatusStatus
OKOK
OKOK
PlannedPlanned
PlannedPlanned
STATUS REPORT onSTATUS REPORT onElectromagnetical Perturbations on the Electromagnetical Perturbations on the Hardwired Safety AlarmsHardwired Safety Alarms
Revision of the shielding and Revision of the shielding and grounding of the existing grounding of the existing hardwired networkhardwired network..
Review of the existing cable paths and rack location
First TIS and EMC consultant audit Recommendations by TIS expected
middle October 2001 Work on the cable connections,
terminations and shielding start middle October 2001
StatusStatus
OKOK
STATUS REPORT onSTATUS REPORT onElectromagnetical Perturbations on the Electromagnetical Perturbations on the Hardwired Safety AlarmsHardwired Safety Alarms
Implementation of a data logger Implementation of a data logger on the main hardwired links.on the main hardwired links.
Design, installation and testing of a LabVIEW data logger
Photos of the InstallationPhotos of the InstallationFilters
Data Logging
HW Alarm Terminal blocks