Although the elements that are monitored by the Monitor service are generally referred as signals, there are 2 types of real signals:

  • Counters: they are read periodically (indicated in the 'Check status every' field of the Monitor tab) by the Monitor service. No matter how frequently these signal change, the amount will be aggregated.  
  • Signals: they are read whenever they change. By this, we get sure that every value of the signal is stored into the system.

Apart from the real signals, the user can also define virtual signals that will be calculated upon the need of the project:

  • UDL signals: this signals are managed into the UDL module, or User Defined Logic, useful to develop new functionality on top of the system.

WARNING: to use Pulses signals instead of Counters signals to count results or consumptions it is not recommended since the system might not read these signals fast enough or possible failures in the conexion with the OPC Server could result in an information lost.