Specifying a Schedule

Topology > 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 Device 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:

Navigate to the Topology activity | I/O Devices.
Click New Device on the Command Bar. The
Double-click the Express I/O Device Setup icon in the Communications folder of the current project.
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).
Fill out the schedule fields to achieve the desired schedule. For example (all based on a Synchronize at time of 10:00:00).

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.

If you enter 12:00:00, and start your project at 4 p.m., the I/O Server will communicate with the I/O Server at 10 p.m., then again at 10 a.m. of the following day, etc. i.e. it will assume that communications were established at 10 a.m., so it continues as if they had been, communicating once every 12 hours after 10 a.m.
If you enter 3 days, and start your project at 9 a.m. on a Wednesday, the I/O Server will communicate with the I/O Device at 10 a.m., then once every 3 days after that, i.e. 10 a.m. on the following Saturday, then at 10 a.m. on the following Tuesday, etc.
If you enter the 6th of December in the Repeat every, and start your project during November, the I/O Server will communicate with the I/O Device at 10 a.m. on December 6, then again on December 6 of the following year, and so on.

Select On Startup for a persistent connection. To disconnect a persistent connection, you need to call the IODeviceControl() function with type 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.