Modicon M340 PLCs Addressing
Examples of Modicon M340 Modbus and Character Mode Addressing
At a Glance
The following examples deal with:
Modbus addressing
Character mode addressing.
Modbus Addressing Rules
The syntax of Modbus addressing is ADDM (’r.m.c.node’) . The meaning of the string parameter is as follows:
r: rack address. The processor’s rack address is always 0.
m: module address. The Modicon M340 processor’s slot number in the rack is always 0.
c: channel address. The Modicon M340 processor’s serial port is always channel 0.
node: slave number to which the request is being sent. The range for configured slave numbers is from 1 to 247.
NOTE: In a Modbus Slave configuration, an additional address, number 248, is used for a pointto-point serial communication.
Serial Link Using Modbus Protocol
The diagram below shows two Modicon M340 processors connected via a serial link and using
Modbus protocol:
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The address settings of the slave processor number 8 are ADDM(’0.0.0.8’).
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Modicon M340 PLCs Addressing
Character Mode Addressing Rules
The syntax of Character mode addressing is ADDM (’r.m.c’) or ADDM (’r.m.c.SYS’) (SYS can be omitted). The meaning of the string parameter is as follows:
r: rack address of the connected device.
m: module address of the connected device.
c: channel address of the connected device.
SYS: keyword used to stipulate the station server system. SYS can be omitted.
Serial Link Using Character Mode Protocol
The diagram below shows a Modicon M340 processor linked to a data entry/display terminal
TM8501:
The address settings of the TM8501 terminal are ADDM(’0.0.0’) or ADDM(’0.0.0.SYS’).
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