Walkerok Posted September 1, 2011 Report Share Posted September 1, 2011 I was faced with a problem yesterday on a different PLC brand where certain pieces of data were lost after the unit had been sitting on a shelf as a backup for the customer for too long. This brought me to think about what I need to do for Unitronics products to avoid the same fate at some point in the future. Lets take an easy scenario. I have a PLC that I am using to monitor different limit inputs on a machine. For each of these limit inputs I have a fixed amount of time I want to wait to avoid nussance shutdowns and alarms. I do not want the user to have access to the delay times so that the times can not be extended from what I have set. I typically block the ability of the useer to get to info mode so that they can not change data in my program through that particular doorway so info mode will not be available to manually re-enter the times to key limit delay timers. In its simplest form I have a net that says that if I0 is true for 3 seconds then make MB0 true to trigger an alarm or shutdown depending on a decision set that is enterable by the user. When the battery dies (hopefully 7 years into the future and not sooner) I am assuming that this information will be lost with no user ability to re-enter all of the appropriate time delays. The question is what is my best way to protect key pieces of data even after a battery failure so that only the user enterable variables would need to be re-entered after a battery failure? Flash burned table, loading values into MIs and T variable on first scan every time, other solution? I am looking at this for Jazz, M91, and V series controllers. Quote Link to comment Share on other sites More sharing options...
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