RKI Instruments M2 Series - Manual (Page 57)

M2 Transmitter Operator’s Manual 52
Termination Jumper
The M2 includes a 2-pin termination header (see Figure 9) that is used when the M2 is
used in a Modbus system. Every M2 is supplied with a termination jumper (a jumper
block) installed onto this header. If the M2 is not used in a Modbus system, this jumper
has no function. When the M2 is installed in a Modbus system, this jumper must be
installed in an M2 that is at the end of a Modbus line. Any M2 in a Modbus system that is
not at the end of a line must have the termination jumper removed (see Figure 29 &
Figure 30 below).
Figure 29: Multiple M2s in a Daisy Chain Configuration
Figure 30: Multiple M2s in a Two Branch Configuration
Modbus
Master
M2
Termination
Jumper
Installed
M2
Termination
Jumper
Not Installed
M2
Termination
Jumper
Not Installed
M2
Termination
Jumper
Not Installed
M2
Termination
Jumper
Not Installed
ID = 128
ID = 127 ID = 126 ID = 125 ID = 1
Up to 128 M2s can be connected without a repeater.
RS-485 RS-485
Modbus
Master
M2
Termination
Jumper
Installed
M2
Termination
Jumper
Not Installed
M2
Termination
Jumper
Not Installed
M2
Termination
Jumper
Not Installed
M2
Termination
Jumper
Not Installed
ID = 1
ID = 2 ID = 3 ID = 4
M2
Termination
Jumper
Installed
ID = 128
ID = 127
Up to 128 M2s can be connected without a repeater.
RS-485 RS-485