Hot download: analysis

Apart from the exceptions described in the previous paragraph, it is therefore possible to change code 1131 and also add new variables, transferring the new program to the target without forcing stoppage.It must however be emphasised that this feature should be the prerogative of maintenance of systems that expressly require the continuation of the operating cycle to avoid prolonged and costly stoppages of production in continuously operating plants.Other than in these situations, it is always advisable to run a full download, also to guarantee the possibility to run hot downloads in future. GF Project VX Code processes the changes made by the user with the aim of maintaining the best possible compatibility with the previous code; for example the addition of new variables is carried out by adding them to the end of the existing memory, not positioning them in spaces left by the elimination of obsolete variables. This operation cannot be carried out indefinitely. Upon reaching the memory limit, the system has to reuse any empty spaces; the operation requires a sort of defragmentation of the declaration of the variables memorised and consequently a full download.Attention: the addition of new variables with hot download also implicates that these variables, even when global, are not available from the user interface. The update of the user interface database is only envisaged for the full download: the cost of this operation in terms of time contrasts with the immediacy of the code swap that the hot download provides.