Fault Finding; Site Visits - Siemens ST950 Plus+ User Manual

ST950 Plus+ User Manual
F F
AULT INDING
9
This section contains information to assist in location and diagnosis of faults.
Equipment Replacement
When replacing any components (including cards) only approved spares may be used. Use of
any other components may invalidate the Type Approval of the equipment.

Site Visits

This section provides a reminder of considerations to be made before visiting a site, and actions
to be taken on site and before leaving.
For the tools and essential spares required when making a site visit, see section 1.4.2.
9.1.1 On Receipt of a Fault Report
When a fault report is received it is recommended that the following are checked:
a) Is the fault a repeat one; i.e. is the fault and its cause known from previous visit. Why
was the controller left faulty? Can it now be cleared? I.e. are the resources now
available to clear it; if so go to site. If not, make an appropriate note in the fault
recording system, or on your fault report.
b) If the report is DFM, i.e. detector fault, check to see if a fault is known to exist on the
site, especially if the fault is reported by an OMU as it may be a repeat alarm for a
reported fault. Because, unlike the controller, most OMUs cannot be made to ignore
faulty loops which have already been reported and, therefore, continue to raise the
alarm.
c) If the controller is under UTC control, check with UTC centre to ensure that the fault
report is not a result of any problem with the UTC, e.g. OTU may be out of action or
faulty.
d) If the Signal State is reported as being All Out, All Red or not giving right-of-way to
one approach try and check with the local authority/police as to whether they know
of a requirement for the signals to be in this state.
e) Check that after clearance of the fault the controller may be re-commissioned and
switched on again; in some cases the local authority may require the signals left off.
9.1.2 Before Going to a Site
Before leaving for a site visit, it is recommended that the following be checked:
a) Check that you have the correct equipment and sufficient spares to do the job you are
going out to do. See the spares list Appendix A.
b) Check that all your spares are good; i.e. check that the replacement cards have labels
with test and inspection stamps on them. Ensure that none of the cards have labels
on them that would indicate they are suspect or have been removed from a faulty site.
ST950 Plus+ User Manual Page 136 of 176
667/HE/53000/000
Issue 2
Unrestricted