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