Modbus Client

When Logo is a client, then it must know the server. This means:

  1. IP address and the Modbus port number if it does not have the default value

  2. All information to be accessed what and where.

There are two way to operate:

  1. Add a network analog input or network input. Then set parameter read from remote device and select Modbus with all its properties. 16bit wide holding registers can be directly read. Larger might not work well since the external modbus might to refuse sending value fragments.

  2. Add a network analog input or network input. Then set parameter read from local variable memory (VM) and select address of the local memory. Now the virtual memory needs to be configured to get the modbus data. This is done via Tools > Ethernet connection. This way also wider than 16bit values can be read, however they got split into different 16bit wide registers and LOGO!8 can just process 16bit wide values. Mathematical instructions (+-/*) might be added to get some useful results out of such fragmented values.


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