Issue
Process to setting up IO scanning in the M340 to communicate to other devices

Product Line
Modicon M340

Enviroment
Control Expert
Unity Pro

Resolution
Note: In M340 IO scanning can only be done through the NOE module. The embedded Ethernet port on the processors does not support IO scanning.

Open you Unity M340 project and in the Project Browser under Communications right Click on Networks and choose New Network...





For the List of available Networks pick Ethernet and give the network a name (default is Ethernet_1)
Note: If the NOE is not in the configuration or the chosen M340 PLC does not have and Ethernet port then Ethernet will not be and available network in the list.




Next open the Ethernet Network to configure it. Make sure the Model Family lists the NOE module not the PLC. Under Module Utilities choose YES for IO Scanning.
Configure the IP parameters according to your network topology.



Click on the IO Scanning tab to fill out the IO Scanning table. The M340 IO Scanner Table is modeled after Premium not Quantum therefore all read/write address need to be consecutive.

1) Under the Master %MW Zone choose the Read and Write Ref start points. These will be the starting register addresses (Master Objects) in the M340 to which data will be Read to or Written from.
2) Fill out the slave IP address, Unit ID, Health Timeout, and Rep rate according to your specifications.
3) Fill out the Slave Indexes and Read/Write length. Note that as you fill out the Length the To field of the Master %MW zones is automatically updated.

The Example below show that the NOE will be Reading 10 consecutive words from %MW0 in the slave to %MW0 in the M340 as well as Writing 10 consecutive words from %MW100 in the M340 to %MW55 in the slave. Note: Because the Read and Write are on the same line the NOE will perform a Function Code 23. If the slave device does not support function code 23 then the device should send an exception back to the NOE. The NOE will then break up the message to Function Code 3 and Function Code 16 for separate read and write requests. It is still recommended best practice to separate the reads and writes into different IO scanner lines if it is know that the device does not support Function Code 23.



Next the Network needs to be linked to the NOE. To do this first open the configuration and Double Click on the NOE module.



Finally in the NOE configuration click on Channel 0 chose ETH TCP IP as the function and Your Network Name (default Ethernet_1) as the Net Link.



Build and download the project to the PLC.