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Event script language (ESL)

ESL is an easy procedural language adapted to work in D2000 System environment. It allows to implement a wide scale of algorithms, which are necessary when creating the system application in a technological environment.

Basic features:

  • own algorithm is expressed in text form, as a source text (script),
  • basic (and integral) executive unit of the language is action,
  • allows to implement and call procedures within one script,
  • calling other scripts by means of the procedural method,
  • error state handler,
  • starting external processes,
  • declaration and use of global and local variables (within the frame of procedure),
  • work with values of objects, using them in expressions, changing them,
  • according to the context of script usage (Script, Active picture), it provides additional possibilities ,
  • use of system objects in a specific way:
    • Historical value - work with the archive (read, block read, write),
    • Database - access to SQL database (read, write, delete),
    • I/O tags - reading, writing,
    • Pictures, Graphs, Compositions - to open, and close on the D2000 HI process's desktop,
    • HI process - communication with operator - text messages, queries,
    • Structured variable - work with structure items,
    • Alarms - to block or to acknowledge,
    • External function - calling external functions implemented in DLL libraries,
    • Process - communication with a process by means of text messages (COMMAND).
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