There is no scan rate directly associated with the script processing itself. In fact the execution is instant, as soon as the value has changed. The script expression will be checked whenever any of the points are updated (a value is input, or the value is changed in some way).

CX-Supervisor is an "event-driven, object-oriented" system meaning that it is actually the points changing that force the script code to re-evaluate the expression. They do this whenever a point changes value, or is re-evaluated (e.g. a value is received from the PLC at the point's usual scan-rate). This removes any sampling error associated with polling and also makes CX-Supervisor very efficient.