Specifications

Tritech International Ltd SeaKing System Options OM
Issue 3 TIL – Eng – Spec – 040 Page 35 of 44
OPTION 8: SETTING SCU CLOCK VIA SERIAL NMEA MESSAGE
This option is available in SeaKing surface software V1.53 onwards and now supports a number of
NMEA 0183 message formats;
1. 'ZDA'
2. 'RMC'
3. 'GGA'
4. 'GLL'
Note: 'RMC', 'GGA', 'GGL' formats are primarily used for GPS position inputs and to enable these
message types, an Application with a GPS panel must be selected (see earlier Option)…
Click on 'Menu' ->
Choose 'AppSetup' ->
In drop-down list, select Application that includes 'GPS' (e.g. 'S_GPS' = Sonar + GPS).
The 'ZDA' message format does not require a GPS Application to be running but does require the
serial COM port to be enabled in the 'Remote' panel Setup menu (spanner icon). Note, that the
'Remote' panel does not appear in certain "single device" Applications such as Sonar only (App =
'S') where an 'S_GPS' would need to be alternatively selected in any case.
The 'Set SCU Clock' option will become active by configuring a command line within the software
initialisation file on the Surface Control Unit. Edit the C:\Windows\Sonv3so.ini file and move down
to the following section…
[NEMA]
;;Set clock via NMEA "ZDA" GPS Time
;;0=Off, 1=1 minute update interval, 2 = Max update Interval
MIN_TIMER=0
The last line (MIN_TIMER=x) sets the option;
1. To disable and SCU Clock setting via NMEA messages, set MIN_TIMER=0. Note, this will not
disable the other SCU Clock setting via the ':SB' V4 serial command.
2. To set the SCU clock with NMEA messages received at 1 minute intervals after 1
st
received
message, set MIN_TIMER=1. For instance, if NMEA messages were received every second,
59 of these messages would be disregarded and the 60
th
would be processed to set the SCU
clock.
3. To set the SCU clock with every NMEA message that is received, set MIN_TIMER=2.
Updating the SCU clock periodically is recommended to keep in synchronisation with other devices
on the system. Every time that the SCU clock is set, this will also have the affect of updating the
onboard clocks in Profilers, Sonars, Bathys and Sidescans, as data time-stamping is handled in
each of these devices.