User’s Manual INNOMAR Parametric Sub-Bottom Profilers / SESWIN 81
Innomar Technologie GmbH (2023-01) 81
6 SBP Synchronisation (Trigger modes) / 1-PPS
There are two BNC connectors (“Sync IN” and “Sync OUT”) at the
INNOMAR SBP front panel that can be used for the synchronisation of the
SBP with other acoustical equipment to minimize inferences.
This must not be mixed up with time-syncing the INNOMAR system clock or
data acquisition time-stamp to an external time source. For this you may
feed a 1-PPS pulse into the topside unit, see section 6.5 on page 88.
The different modes for the INNOMAR system synchronisation
Internal (INNOMAR SBP stand-alone or “master” device)
External (INNOMAR SBP “slave” device, triggered by other equipment)
Alternating (INNOMAR SBP master device, pinging alternating with external device)
have to be set in the dialog “System Setups – General – Synchronisation”, see section 5.11.3 on
page 60. These settings are described in the following subsections.
The actual trigger mode is indicated in the SESWIN status bar: INT / EXT / ALT
6.1 Internal Synchronisation
For this the “Synchronisation Mode” in “System Setups – General –
Synchronisation” has to be set to "Internal Trigger". INNOMAR SBP runs
free and may be used as master device to trigger other devices. The
optimal ping rate, depending on the range settings, is calculated by
the INNOMAR SBP.
“Sync Out” outputs a RS232 signal that can be used to trigger any other devices. Voltage levels
are up to -±10 V (typ. ±6 V). Make sure these voltages can be applied to the device to be
synchronized.
The “Sync OUT” pulse is active (high) for about 1ms and the system pings at the falling edge
(high to low transition) of the “Sync OUT” signal, see figures below.
Any signal at “Sync IN” is ignored in this mode. But voltage levels applied to this input must not
exceed ±15 V as higher voltage levels may destroy the electronics.
The ping rate can be estimated as follows. Between subsequent pings there is a dead time of
approx. 10 ms. Supposing a sound velocity of 1,500m/s, the resulting ping rate in “normal”
ping mode (internal trigger) is:
The trigger pulse at the “Sync OUT” connector can be set to be longer than 1 millisecond, but the
INNOMAR SBP will still ping after 1 ms from the rising edge. This feature can be used to get a
Transducer Ping
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