Nesis III — Installation Manual
9. Service Port
main bus
Nesis Airu
Nesis master
Daqu
120 Ω
Figure 25:
Topology of Nesis basic kit – Daqu also serves as a bus terminator.
Because the main bus is very short, second terminator is not really
needed.
main bus
Seru
J
Figure 26:
Devices with only one CAN connector require T-junction.
8.2.2
Terminator Plug
Nesis usually works together with Daqu and special terminator plugs are not
required. But there are some occasions (to run Nesis as a standalone device,
for example), when the terminator plug is needed.
The terminator is nothing but a simple 120 Ω resistor between CAN high and
CAN low leads – pins 4 and 5 on Figure 22 and Table 4. A standard 1/4 Watt
resistor will do.
9
Service Port
The service port consists of a D-SUB 9 pin connector and it is a multipurpose
port. The port supports several roles: terminal communication with the built-
in computer, auxiliary RS-232 port for general use, autopilot release command
and alarm output signal. All functions can be used in parallel, although this
is seldom needed.
Figure 27 and Table 5 define role of individual pins.
9.1
Terminal Communication
Terminal connection is used for communication with the main Nesis computer.
This is a classic RS-232 connection at 115200 bit/s, 8 bits data, no parity bit,
35
©
Kanardia
2018
