Geo1000

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About Geo1000

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  • Country United Kingdom
  1. Function Block addressing

    Hello all.  I have a program which has 8 function blocks. I recently added extra functionality to one of the programs (not the function blocks). I added the new variables to the global symbols table and added the new code, but when I compiled the new code, the variable addresses in three of the function blocks had changed. This is a problem, because we use memory cassettes to download new versions of code, so when the new version is downloaded to a machine in some far flung part of the world, these variables will be overwritten (they are hours run variable, so are important for servicing purposes).   My understanding is that CX assign's variable addresses in Function Blocks and we have no control over this. Bit if I only added variables to the Global symbol table, why are the FB addresses affected??   Any input appreciated. 
  2. Internal function block variables

    Ah, but the problem is that address H1420 in the old code holds a value I don't want to delete (it's an Installation Date variable). The address in the new code needs to be  H1420 as well otherwise when I download it, the display shows a meaningless variable as the original H1420 has been overwritten. The other problem is that the code is being downloaded using a memory cassette, so there is no way we can change the variables as the field operatives don't have CX one.........
  3. Internal function block variables

    Thanks Michael. I tried that, but it threw up a compile error saying 'This address is reserved for Function Block use'........ I've spoken to my service team and they are okay with the values being over written, but it's annoying me.  Thanks again
  4. Internal function block variables

    I have a function block where the first internal variable is showing as address H1420 in the Global Symbol table. When I add another retained variable to the function block then save and compile the code, the variable address in the global symbol table shifts from H1420 to H1488.  I need to retain the address as I will be downloading code and I need to ensure the address if H1420 stays with that variable.    Can anyone help with this?
  5. Omron Function Block variables

    Hello all.  I posted earlier in the week regarding downloading new code to an Omron PLC, but I think the question was a bit vague. As a follow up, and hopefully to clarify, I have the following query. I have created an upgraded program which will be downloaded by field techs using memory cassettes. The revised area of code is essentially a Function Block which amends service lamp behaviour, and in creating it, I have amended the existing function block and added new Internal variables. Is there any way I can ensure that the new variables don''t over write or move the existing  variables in the PLC, because this is what is happening when I download it.    HELP!!!!!!!!!
  6. Geo1000

    Hello all, I have a problem with PLC at work. I am working on historical code with a view to upgrading it for a roll out program to all site based PLCs. The code is to be downloaded using memory cassettes, and there is data on the PLC's which needs to be retained. I have re-worked the code and it performs as I would expect as per the following: 1) I download original code (V2.01) to PLC using CX1 2) The PLC simulates a cycle and various values are stored (the key variables are Installation Date and Service Due date). 3) I then download my code to the PLC and the variables have been retained. All so good so far.   The problem is that the factory production line uses PLC code saved using the PLC Backup Tool. When I download the original code to the PLC using this tool, I encounter various issues, but the main one is to do with real time PLC clock values. When I download the code direct from CX one developer,  I use the MOVD(083) instruction on A352 through four to give me a variable with the date, month and year. This morning (29/01/2019) the BCD values read as 41, 1 and 25, which translates to 29 (0010 1001), 1 and 19 (0001 1001). When I download the backed up code using the PLC  Backup tool, the values are totally different. I have run the backup files for both codes through a comparison program and there are no differences between them at all....... Can any one advise if they have experienced this before??   Thanks.