Siemens Mobility, Traffic Solutions
Sopers Lane, Poole, Dorset
BH17 7ER
GPS CLOCK Facility Quick-start Guide
Need for GPS Clock
In locations where the mains supply is irregular and CLF is implemented GPS clocks allow a good standard of site
co-ordination to exist without constant clock maintenance.
The GPS clock Facility is available for the ST800, ST900, ST700 and ST750 families of Traffic and Pedestrian
controllers.
The Clock Kit consists of the following parts:
Antennae with 30M cable (The Antennae cable must not be extended without consulting Engineering at Poole).
Connector set including Antennae cable adaptor
GPS module and fixings
GPS Kits.
There are two styles of GPS kit the main difference is the style of connector to CPU card. It can clearly be seen in
the images (Figure 1 & Figure 2) below that the CPU connectors are different.
The Kit part numbers are:
667/1/27014/000
Suitable for ST800, ST900, ST900ELV, ST750ELV
667/1/27014/750
Suitable for ST700, ST750
The Kits are dispatched with a drawing indicating the position to fit the GPS module. If local conditions dictate the
GPS modules location may be changed. However in all instances the GPS module must be secured to suitable
metalwork and the cables secured to ensure no strain is placed on the connectors or module.
The Antennae should be mounted on a signal head or it’s bracket, on a pole adjacent to the controller but free from
close obstructions such as buildings or trees.
The Power for the GPS module is obtained through the lead supplied and the lead should not be shortened or
otherwise modified due to the risk of incorrect assembly or poor connections to the IDC header
Position of interface cable on ST800, ST900 ST900ELV and ST750ELV
The cable set from the GPS Clock plugs into the CPU card (ST900 CPU card shown but the connector is in the
same position on the ST800 CPU). The Connector is shown marked X8 in the bottom middle of Figure1.
Figure 1
Version
Last Editor
Document
Name
1
Page 1 of 2
Mike Tonkin
GPS CLOCK Facility QS guide
Copyright © Siemens plc 2011 All Rights Reserved
Status
Issue 1
Date
07 June 2011
Doc. No. 667/HQ/33900/000
Siemens Mobility, Traffic Solutions
Sopers Lane, Poole, Dorset
BH17 7ER
Position of interface cable on ST700/ST750
The cable set from the GPS Clock plugs into the CPU card PL12 shown in Figure 2 marked MODEM.
Figure 2
Controller Setup for GPS
It is recommended that the Controller be set to run on crystal clock. CTS=2
The Clock date/time should be set up in accordance to the appropriate handbook.
Other than that no other set up is required for the GPS clock to operate however see the note below:
The Controller will not consider synchronization if its clock has not been set-up, e.g.
• fault ‘FLF 7:255 RTC’ is set.
Time zones where half hour zones are implemented
If the local time zone is not a full number of hours offset from GMT then the clock should be set 30 minutes
retarded. The GPS clock does not correctly synchronise to the half hour. The Cableless linking plans and other time
switch functions should take account of these 30 minutes when the time switch is being configured.
Clock synchronisation operation
The Controller only synchronizes its minutes and seconds from the GPS Clock. The date and hour are not ‘adjusted’
because the GPS Clock returns ‘UTC’ time (Coordinated Universal Time), which does not take time zones or
daylight saving into account. The user is responsible for setting the clock to approximately local time, which the
controller will then adjust using the minutes and seconds from the GPS Clock. If daylight changes to the controller’s
clock are required, the controller must still be set-up as normal, see the handset commands BSA and CKA.
The Time displayed with the CKM command shows GPS time corrected to UTC which is formatted as follows:
CKM:$GPRMC,hhmmss,status The Status is either a letter V or A where A means available and V not available.
The command CKS will respond with the date and time that the clock was last synchronized with the GPS clock.
Once the clock has synchronized it will not attempt to synchronies for a 1 Hour.
The Controller will not attempt to synchronies the clock if the change in time will take the clock through a full hour.
This is to prevent problems with day/date.
Associated Documents
667/HH/32900/000
Handset Handbook for the ST900 and ST750 Families of Traffic Controllers.
667/HH/27000/000
Handset Handbook for the ST800 and ST700 Families of Traffic Controllers
667/CH/27014/000
GPS clock kit modification (Supplied with GPS Kit).
The /CH/ document is supplied with the GPS Kit.
The /HH/ documents can be found on the Siemens Traffic Solutions Downloads Webpage.
Version
Last Editor
Document
Name
1
Page 2 of 2
Mike Tonkin
GPS CLOCK Facility QS guide
Copyright © Siemens plc 2011 All Rights Reserved
Status
Issue 1
Date
07 June 2011
Doc. No. 667/HQ/33900/000