Simrad SC90, Installation Manual

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419050/B
Synchronization using Clear To Send (CTS) and Request To
Send (RTS) signals
In many applications, the synchronisation interface is based on an RS-232 serial port.
Only the Clear to Send (CTS) and Request to Send (RTS) connections of the RS-232
interface are then used.
According to the standard specifications for RS-232, an output must generate a voltage
level of +5 to +15 VDC (logic "low"), and -5 to -15 VDC (logic "high") into a load of 3
to 7 kΩ. An RS-232 receiver must present a 3 to 7 kΩ load , converting an input of +3 to
+25 VDC to logic "low", and an input of +3 to +25 VDC to logic "high". With a positive
trigger pulse, the offset voltage does not have any significance. Even small variations
(flutter) over and below 0 VDC will not trigger the interface.
A
Local connection
B
Connection on remote device
C
Female 9-pin D-connector
D Male 9-pin D-connector
Note
RS-422 communication ports can not be used for
synchronization purposes. The port you wish to use must
be set to RS-232.
Serial line 1 (COM1) is used to communicate with the Operating Panel.
Synchronization sequences
In many applications, the synchronisation interface is based on an RS-232 serial port.
When you connect two systems for synchronisation using Clear to Send (CTS) and
Request to Send (RTS), one system must set up as a "Master" and the other as a "Slave".
When the SC90 is "Master" in a system, the synchronization can either take place in
Free
running mode, or in Wait for slave mode.
Slave mode
When the SC90 is set up in Slave mode, it must receive a trigger signal from a peripheral
system every time the SC90 shall transmit. This trigger signal is connected to a serial
port on the Processor Unit, and the Clear To Send (CTS) pin is used to give the SC90 an
Simrad SC90 Installation Manual