Limitation to address in Vijeo Citect 7.4

By the way, I have one question. Is there any limitation to address in vijeo citect. Because I only can assign variable tag of string with address S510. But when I start to assign at S511 and above, it says unknown error. what happen?

hello Aimin, I do not know the answer to your question. But just a little bit of advice. The information in the thread subject will be more useful to whoever may be able to help you if you use something more specific than "Need help", because in general, whoever starts a thread does so because he or she needs help. In this case, something like "limitation to address in vijeo citect" may catch the eye of a CITECT experte and thus increase the probability that you will get a neaningful and useful answer.

Oh thank you for the advice sir. That's a good tips for me. I will edit it now. Thank you!

I found the following old document refering to Citect V3.00, but it seems it still applies today. The limit for String (S) is indeed S510.

I finded this for newer Citect versions. So there is no limit to PLC address anymore, but varible record number must be less than 511, Which limits overall string to 512 variables?



Q3401 Using Strings with Memory PLCs




I am using a memory device with the OPC protocol and getting a #MEM on some of my string data types. I only have a few strings Tags defined. Why is this happening?


Solution: The Memory I/O Device allows the user to configure Variable Tags with "real world" addresses for the chosen protocol (eg. OPC). However, reads and writes to the I/O Device are actually handled by a dedicated Memory Device driver. In Citect v5.21 you are restricted to 255 Tags of the STRING type when using memory devices. In Citect v5.30, you can have 510. In Citect v5.31 or later, the number has been increased significantly.
However, the OPC and other Citect Tag Based Drivers (TBDs) compile with the Tags address passed as the Variable.dbf record number. So if for example, you have one string as the 600th Tag in your Citect v5.30 project, then it will be passed with address 600 and so fall outside the maximum address of 510 and result in a #MEM error. To avoid this happening, the user may need to sort their Variable.dbf file to place all STRING Tags at the top of the file.


NOTE:
If you have a networked system using the OPC driver, every copy of the variable.dbf must be exactly the same.
Contact Citect Customer Service if you are unsure of how to sort the Variable.dbf file and ensure you make a backup before making any changes.

Oh I see.. Thank you so much both of you guys.. It was so helpful for me to know that. Thank youuu!! :site:

Aimin, great you got helpful answer!