Fault Finding Starting From The Fault Indications - Siemens ST950 Handbook

If the visit is to investigate a reported fault, on arrival at the site proceed as follows:
Check all signal heads to see what signals are being shown to the road users, if
any. Open the controller door. Now check the controller `visit log book' to see if any
previous visits/faults are similar, as previous actions may have a bearing on this
visit. Make a visual inspection of all of the wiring and cards.
Check for any entries in the Controller fault table and System Log.
Now proceed with the fault diagnosis.
10.2

Fault Finding Starting from the Fault Indications

The following is a list of indicators in the ST950 controller that assist in the location
and diagnosis of a fault. The state of each of these indicators should be noted on
arrival at a site before doing anything else.
10.2.1 Cabinet Alarm Indicator
The LED (behind the manual access door) is normally lit when the controller has
identified a detector fault, and flashes when the Controller has detected a red lamp
fault.
In some installations, the Cabinet Alarm may be lit for other reasons - refer to the
Works Specification.
10.2.2 Master Switch
This removes the mains supply from the entire controller when opened, i.e.
switched off. Depending on cabinet installation this is normally mounted on a panel
at the bottom of the controller.
10.2.3 Controller Switch
This is normally included in the MDU and removes power from the equipment rack
and equipment powered from it. This is a single pole switch so does not provide
safety isolation. Also note that the maintenance socket is still powered when the
controller switch is off.
10.2.4 CPU Card LEDs
When the controller is initially powered up, it performs various internal checks
before starting normal operation. While these checks are being performed, the
green heartbeat LED flickers and the red system error LED remains illuminated on
the CPU Card.
If these tests fail, it would point to a serious fault on the CPU Card and it should be
replaced. The error message is repeatedly written to the handset display at 1200
baud, and no other handset operations can take place. See the ST950 Family
Handset Handbook for full details.
If the SE (System Error) light is on, then the processor will have shut the system
down and logged a fault – check the fault log.
Security classification
Version
Last Editor
Document Name
Copyright © Siemens Mobility Limited 2018. All Rights Reserved.
Unrestricted
5
Neil Atkinson
ST950 ICM Handbook
Intelligent Traffic Systems
Sopers Lane, Poole, Dorset, BH17 7ER
Page 88 of 125
Status Issued
Date 18-Dec-2018
Document No. 667/HE/46950/000