I am developing a power monitoring system for our substation and aiming to transfer the data to a PLC. The system lacks proper documentation since its installation a few years ago. At present, the PanelView utilizes Modbus communication through Kepware to showcase substation data, along with Ethernet communication for PLC communication. All communication is managed through a Stratix 5700 switch. The PLC model 1756-L7 currently does not have access to real-time substation data, only an Ethernet card. An example of the Modbus tag used in the HMI is: Building_2578_Sub84_Channel1C.Janitza_1C.II841C-L1. Is it feasible to extract data from the HMI or ethernet network to the PLC? Does the PLC require a Modbus card for the rack? I have conducted research and found references to a Modbus AOI for the PLC but have not found detailed information on it.
Update: Through my investigation, I have discovered that the PanelView is utilizing Kepware to collect data from the power substation. The substation itself employs Janitza power analyzers for data collection and transmission. After some persistence, I successfully accessed the Kepware file and identified the Modbus codes for the transmitted data. I am currently delving into the Rockwell Modbus AOI to explore the possibility of capturing the data on the network. With a total of 12 Janitza power analyzers sending data, it appears that I will require 12 AOIs to accommodate them all. These AOIs appear to be quite extensive in size. Despite the challenges, I am determined to make this solution work. Interestingly, the installer opted for a 1756-L74 controller which seems to have minimal information available, only featuring tags from a few remote direct inputs.
It's absolutely feasible to extract data from your HMI and inject it into your PLC. The 1756-L7 can indeed benefit from a Modbus card if you're planning direct Modbus communication. The Modbus AOI (Add-On Instruction) you mentioned can be implemented without the need for an extra card. It is an instruction set that you incorporate into your PLC's ladder logic, enabling your PLC to decipher and utilize Modbus communication. Nonetheless, it's worth noting that this method might require a level of programming familiarity. Rockwell Automation's website provides some good resources and tutorials to better understand this if you need help there. Double-check your system's specific needs before investing in additional hardware, as this may not be necessary in all cases.
Absolutely, you can extract data from the HMI or Ethernet network to the PLC. In your setup, you will likely need to utilize a Modbus TCP/IP protocol given that your Ethernet and Modbus communication are already established. For your PLC model - the 1756-L7, while a Modbus card is an option, it isn't strictly necessary. If your system is not overly congested, you can communicate directly through the Ethernet card using the Modbus TCP protocol. As for the Modbus AOI you mentioned, it's a pre-defined logic block designed to make Modbus communication simpler in a PLC. Rockwell Automation provides a great AOI solution for their PLCs, and I'd recommend looking up their literature for the exact implementation. So, while it may look complicated, you've already done much of the foundation work. Start exploring the Modbus AOI's, and you'll find a pathway to achieve your goal.
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Answer: - Yes, it is possible to extract real-time substation data from the PanelView to the PLC using Modbus communication. The PanelView currently uses Modbus communication through Kepware to display substation data.
Answer: - The PLC model 1756-L7 has an Ethernet card but does not have access to real-time substation data. It may require a Modbus card for the rack to enable communication with the substation data.
Answer: - References to a Modbus AOI for the PLC have been found, but detailed information on it might be needed for successful implementation of data extraction from the HMI or Ethernet network to the PLC.
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