Modnet communication

Q1: I think it should be no problem to create multiple units at the same address.  Just configure them as different I/O Devices and give them each a unique number.  They will all be associated with a single Port that has the IP Address in its configuration. 

Q2: Yes. See the "Driver Reference Help" for the MODNET Driver.  There is a link to it from the Topology > I/O Devices page of Citect Studio.   See MODNET Driver > MODNET Parameters and you will see a parameter called MaxBits.  You can either set this universally, or if needed you can set a different value for each I/O Device. 

Q1: For this to work, you have to define an I/O device for every slave ID within the device. You can then specify the different slave address numbers in the "Address" field of these I/O devices. All I/O devices can point to the same Citect Port definition which contains the IP address and TCP port (502) in the "Special Options" field.

If you leave the "Address" field of a Modnet I/O device blank, or set it to 0, the driver will send messages to all slaves in the device (default behavior).

Q2: The Modnet driver groups data into blocks of 2000 bits by default. This can be made smaller by setting the Citect.ini parameter [MODNET]MaxBits to a lower value. It cannot be made higher than 2000. Maximum message length is dictated by the official Modbus protocol (253 bytes) I believe.

Thank you for your reply. It was very good to know. I will try it by myself too.

Thank you for your detail answer. Easy to understand. I will try it by myself too.