Start by creating an Ethernet network in Unity. Go to Communication > Networks, Right click and choose New Network.
Choose Ethernet and name the network.
Next configure the network as needed for your application. Be sure to choose the correct Model Family for the Ethernet interface you will be using.
Don't forget to validate your changes.
Next link the network to the Ethernet port of your module by double clicking on the port in the configuration and then choosing the network name.
Once again don't forget to validate your changes.
Open the Variable Declaration and create the following variables.
The RD_Data & Slave_Addr variables are located.
The RD_Data variable is the memory location to where the slave data will be stored in the Quantum.
The Slave_Addr variable is an Array of 5 words where the high byte of the first word is the physical slot that the Ethernet module is in the backplane and the low byte is modbus mapping index.
The remaining 4 words are the IP address of the slave device. In this case 192.168.40.7
If using the embedded port of a Unity Quantum the high byte of the first word should be FE
Next create a new project section, choose a language, and name the section.
In this section add a READ_REG block and link the variables as shown.
The SLAVEREG pin is the starting address in the Slave device from which the data will be read. In this case %MW1500.
The NO_REG pin is the # of registers to be read.
If reading more than 1 register then the RD_Data
variable must be an located Array of INT with a length equal to the # of registers to be read.
Build, download and run the program.