trevorb

Hello, I am using MQTT communication to send and recieve data. I subscribe to a topic and recieve a JSON Payload. The key corresponds to a variable on the controller and the value is the new value the variable is to be set to. My application may have 10, or 100, or maybe 1000 variables that need to be updatable from the UI. Is there a way to use the key (which is a string) as a reference to the variable that is to be updated so i can keep to code concise. Currently my only method of updating the...

Yeah wow. That doesn't look like it will simplify things so will not go down that path. The reason I ask is because AB has an alias option for tags which are a direct reference to the same tag or structure just with a different name. Hoping there was a similar solution here too. Thanks for your response

Hi All, Thanks in advance for any advice you can offer. We use the SEW-Eurodrive MoviC controller using the CodeSys platform. SEW in their wisdom have very long naming convention for their devices. For example. The bit to activate their velocity profile is Interface_Axis1.ProfileGeneration.Velocity.In.xActivate We would like to improve the readability by having a condensed version such as Axis1.PG.Vel.In.xActivate Any thoughts on how we could alias all or parts of their axis structure?

Thanks for the reply. I wasn't aware of the Ethernet/IP using retains by default. Good idea with regard to using the recipes to store the retains in the event of download. It wouldn't be a big deal to detect the loss of power and trigger the save command. Thanks for the tips

Yes I indeed have done this on many occasions to defragment the memory. However, the issue lies in trying to assign 11kB of data into a 2kB memory area.

In concept I understand the approach you are taking to reduce the use of persistent to only that is required. That is a good approach to reduce the usage. The basis for the original question is because my experience is with asked Bradley PLC which by default all tags are non volitile and the smallest storage in the compactlogix range is 600kB program and data storage. I was running out of persistent memory at 2kB so it didn't make any sense that this could not be increased. After discussing further...

Hi Thanks for the response. Using the attribute you have suggested should indeed help utilising all the available data however, for this project it will still be inefficient.

Hi All, I am looking for support for my Codesys application. I am using persistent variables however I am no longer able to add more due to an error when trying to upload changes. The error is below [ERROR] Default: PersistentVars [PCT_Assem_Mach: PLC Logic: Application](Line 229): C0415: Out of persistent memory: Variable 'R314TPEdges1', 1208 bytes (Largest contiguous memory gap 488). Editing persistant variable lists may produce fragmented memory. Perform "Declarations, Reorder list and clear gaps"...