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3.2 MODBUS SLAVE ADDRESS
• A single Modbus network may have a number of slave units attached and these
units MUST have each a unique slave address.
• The 3155 NMEA2000 to Modbus Gateway Slave Address can be set from 16 decimal
to 1 decimal by using the small rotary switch on the front panel labeled “Addr” as
per the following table:
3.3 MODBUS TERMINATION RESISTOR
Please note that this unit does NOT include any Modbus network termination resistor as the
master normally includes this. If this is not the case then a RS485 termination resistor MUST be
included in the Modbus Communication line
3.4 NMEA DEVICE INSTANCE
NMEA2000 requires a unique Device Instance for each 3155 NMEA2000 to Modbus Gateway on
a single network. This is settable from device instance 0 to Device Instance 15 using the lower
small rotary switch on the front panel labeled “Addr”. This can be set at any time regardless if
power is on or off. The switch counts from 0 – 9 then A – F being equivalent to Device Instance
0 – 15.
Please note that this switch also controls the Modbus Slave Address so a compromise address
that suits both interfaces should be chosen.
Switch Position
Decimal Address
Hex Address
0
16
0x10
1
17
0x11
2
18
0x12
3
19
0x13
4
20
0x14
5
21
0x15
6
22
0x16
7
23
0x17
8
24
0x18
9
25
0x19
A
26
0x1A
B
27
0x1B
C
28
0x1C
D
29
0x1D
E
30
0x1E
F
31
0x1F
