Transmission Intervals; Sensor Data Input Port; Figure 53 Input Port Schematic - Raymarine AIS950 Installation Instructions Manual

Technical reference

6.2 Transmission intervals

The IEC61162 sentences are in general output in response to a specific event, such as initiation of a binary
message via the user interface. Certain messages are output over the ports at regular transmission intervals.
Table 11lists each sentence type and the transmission interval.
Output sentence
type
VDO
ALR (inactive)
ALR (active)
ABK, ACA, LR1,
LR2, LR3, LRF,
LRI, TXT,
VDM,RTCM
Table 11 IEC61162 transmission interval for periodic sentences

6.3 Sensor data input port

The sensor data input port schematic is shown in Figure 53. The optional 120 Ohm termination is selectable
via a jumper in the junction box and should be fitted in the 'R' position when long cables connecting to the data
source are required - see section 4.4.4. Each sensor data input port is isolated from other data port inputs and
from the transceivers internal power supply.
In junction box
B
Jumper
Data input
port
120 Ohms
A
GND

Figure 53 Input port schematic

A logical low input is defined as: A-B < -0.2V.
A logical high input is defined as: A-B > +0.2V.
The input impedance is approximately 54 kOhms without the junction box jumper fitted, and 120 Ohms with the
jumper fitted.
Page 56
Transmission interval
once a second
once a minute
once every thirty seconds
Only transmitted when specifically
initiated by an external event
Input B
Input GND
Input A
Comments
Own vessel VDL reports. When a
report is not generated by the
transceiver a 'dummy' VDO is gen-
erated in its place.
An ALR sentence for each internal
alarm is output as a single block
once every minute whilst all alarms
are inactive
Once an alarm becomes active the
transmission interval switches to
once every thirty seconds. The
active alarm is not reported as part
of the block of inactive alarms dur-
ing this period.
Isolated
supply +
Isolated
supply -
To UART