Emerson Exchange 365

Tricky discussion....but "typically" you don't have to reset the parameters. If the phase unloads then the parameters will be as the initial phase configuration when it loads again but if the phase doesn't unload then your parameters will remain as they currently were left at. This situation occurs if you run a phase back to back in an operation so if you never have recipes do this...then you don't have to worry about resetting parameters. If you do run phases back to back from an operation then you may have to do "something". If a transition below a phase becomes true in an operation and the next phase is exactly the same phase, the phase doesn't run stop, reset and reload, it actually just sets a parameter DOWNLOAD_REQ and continues doing what it was doing. It is up to the phase configuration to watch this parameter, get the new parameters by setting REQUEST code 1000 and starting the Run logic over. This IS NOT automatic and has to be programmed! This was done for recipe execution speed to not have to unload and reload the phase but does put some design and configuration on the engineer.

If you are running Unit Procedures back to back that ultimately have the same phase in it...the phase will unload, this DOWNLOAD_REQ is only when the same phase is back to back within an operation. If you do reset parameters you have to be careful because we have seen people do this in the phase and if the phase goes to hold just before being complete...the phase logic was actually re-executed because of the parameter and the logic within the phase on restart. So long story short, I suggest you don't reset the parameters unless the DOWNLOAD_REQ is true and then get the new recipe parameters, reset any default phase parameters, start the run logic all over again and clear the DOWNLOAD_REQ parameter is the only time you should reset the phase parameters.