This video gives basic information on Using the MRX "Modbus Network Read" instruction in the Do-more designer software. It presents information that is commonly missed by users. This WILL NOT be a complete tutorial for the instruction but rather a supplement to the help file and customer experience.
Our FREE Practical Guide to Programmable Logic Controllers eBook: https://go.pardot.com/l/548202/2018-08-06/7n3v42
This instruction works for both Modbus RTU and Modbus TCP When you select The Serial port, this will be Modbus RTU, and the Unit ID will address the slave’s node number. If you select an Ethernet port, this will be Modbus TCP, and you will have these addressing options. Typically the Modbus TCP Port is 502 and the unit ID is 255, consult your slave’s documentation if this does not work. The function code determines what addressing you can read. Notice when you select a function code this changes this part. So if you are trying to read 400001, select function code 3 and you will only need to enter the offset of 1 here. These are the ways that this instruction can be triggered. I usually set the instruction for the following settings with a constant time of 1 second until I can verify I have good Communications. For more information on this instruction click here