Using CitectSCADA > Communicating with I/O Devices > Scheduled Communications > Specifying a schedule

Specifying a schedule

To configure scheduled communications with an I/O Device, you need to flag it as a "Scheduled" device. This is done using the Express Communications Wizard. If your I/O Device is not capable of scheduled communications, the scheduling options will not be presented by the wizard.

Note: Scheduled communications will not work for drivers that are designed to handle Report-By-Exception protocols. For communicating with your I/O Device outside of schedule use the IODeviceControl function.

To schedule communications with an I/O Device:

  1. Select the Project Editor (or press the Project Editor icon).
  2. Choose Communication | Express Wizard or open Citect Explorer.
  3. Double-click the Express I/O Device Setup icon in the Communications folder of the current project.
  4. Follow the instructions to work through the screens, selecting the relevant I/O Device, and so on. When the scheduling screen displays, check the Connect I/O Device to PSTN box, even if your I/O Device is not connected via a modem (but leave the Phone number to dial and Caller ID fields blank).
  5. Fill out the schedule fields to achieve the desired schedule. For example (all based on a Synchronize at time of 10:00:00).
  6. If you enter 12:00:00 in the Repeat every field, and start your project at 9 a.m., the I/O Server will communicate with the I/O Device at 10 a.m., then once every 12 hours after that, i.e. 10 p.m., then again at 10 a.m. of the following day, etc.

  7. Select On Startup for a persistent connection. To disconnect a persistent connection, you need to call the IODeviceControl() function with type 8.
  8. If your I/O Device is not connected via a modem, you need to go to the Ports form (select Ports from the Communication menu) and change the Port number to the actual number of the COM port.

See Also