I am seeking help in creating a program to transfer data from a Station PLC to an AGC PLC in each cycle using a CIP Data Table Write MSG instruction. With a new AGC entering the station in every cycle, the data must be written to the newly arrived AGC, each of which has a unique IP address with varying lengths such as XXX.XXX.XX.XX, XXX.XX.XX.XX, XXX.XXX.XXX.XXX, etc. In this project, a total of 200 AGC PLCs are communicating with a single Station PLC. Due to the large number of devices, I am unable to add all AGC PLCs in my IO tree and determine their paths via GSV. I require a solution to dynamically generate the IP addresses and modify the IP address path for the MSG instruction. I am encountering difficulties with the Length byte and the rack position byte. Any examples or ideas to resolve these issues would be greatly appreciated. Thank you in advance.
In order to ensure proper formatting, the MSG Path string should contain an even number of bytes and be padded with a 0 byte if required. A helpful resource for understanding this concept is the DLR AOI found in the Network Device Library of PCDC. Additionally, the PathToHex AOI can be utilized to convert any string path into a Hex-based path for use in MSG instructions. This tool is especially beneficial for ensuring compatibility and accuracy in data transmission.
In order to generate the message path, I calculated the length of each IP address string and then transferred the characters to the master string by concatenating them all together. Appreciate the assistance provided.
Sounds like you're dealing with quite a complex setup there! It seems like you may benefit from establishing a structured pattern within your PLC IP addresses for effective management. One possible approach is using a combination of FOR loop and an array. You could generate the IP addresses dynamically, looping over a range, and append the value to a base IP. This has the potential to resolve your issue of varying IP lengths. For the Length byte and Rack position byte issue, consider using a Union data type to store the IP address and split it into bytes to manage the different segments more effectively. This should allow for more dynamic allocation. Don't forget to deal with network byte order (big-endian) when you program the PLC as it can be one of the overlooked nuances causing issues. I hope this gives you a jump start in solving the problem. Always make sure to thoroughly test any new scheme to verify its efficiency.
This sounds like quite a complex setup, but I'm sure we can find a way through it. Assuming you're using an RSLogix/Studio 5000, you might consider using an ANSL TCP/IP command to send messages. This method would allow flexibility and dynamic IP addressing, bypassing the IO tree restrictions. Regarding the Length byte and the rack position byte issues, consider exploring the Distributed I/O over CommLinks. It allows remote rack and slot addressing via PLC code, which can be dynamically updated for each MSG instruction. Remember, it's all about creating a proper script that reads the IP format and adjusts the length and rack bytes accordingly. Good luck, and don't hesitate to ask if you need any more clarifications.
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Answer: Answer: You can achieve this by creating a program that utilizes a CIP Data Table Write MSG instruction and dynamically generates the IP addresses for the AGC PLCs as they enter the station in each cycle.
Answer: Answer: Yes, it is possible to handle communication with a large number of devices by dynamically generating the IP addresses and modifying the IP address path for the MSG instruction, thus avoiding the need to add all AGC PLCs in the IO tree.
Answer: Answer: To resolve these issues, you may need to implement specific logic in your program that handles the varying lengths of IP addresses and adjusts the rack position byte accordingly. Examples or ideas from experienced users could provide valuable insights to address these challenges effectively.
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