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Chapter 8: RS-485 Modbus Output
M2A-XL Transmitter Operator’s Manual
Termination Jumper
The M2A-XL includes a 2-pin termination header (see Figure 10) that is used when the M2A-XL
is used in a Modbus system. Every M2A-XL is supplied with a termination jumper (a jumper
block) installed onto this header. If the M2A-XL is not used in a Modbus system, this jumper has
no function. When the M2A-XL is installed in a Modbus system, this jumper must be installed in
an M2A-XL that is at the end of a Modbus line. Any M2A-XL in a Modbus system that is not at
the end of a line must have the termination jumper removed (see Figure 34 & Figure 35 below).
Figure 34: Multiple M2As in a Daisy Chain Configuration
Figure 35: Multiple M2As in a Two Branch Configuration
Modbus
Master
Up to 128 M2As can be connected without a repeater
RS-485
RS-485
ID = 126
ID = 127
M2A
Termination
Jumper
Not Installed
M2A
Termination
Jumper
Not Installed
ID = 128
M2A
Termination
Jumper
Installed
ID = 125
ID = 1
M2A
Termination
Jumper
Not Installed
M2A
Termination
Jumper
Not Installed
ID = 128
RS-485
M2A
Termination
Jumper
Installed
Modbus
Master
Up to 128 M2As can be connected without a repeater
M2A
Termination
Jumper
Not Installed
M2A
Termination
Jumper
Not Installed
M2A
Termination
Jumper
Not Installed
M2A
Termination
Jumper
Not Installed
ID = 2
ID = 3
RS-485
ID = 1
M2A
Termination
Jumper
Installed
ID = 127
ID = 4