Device Communications

Project or System


When an enabled device fails to respond to a read or write request from a device communications driver for several consecutive attempts, it is said to be down and will be polled at the Retry interval rate until it responds.

By default, a device communication driver tries all down devices at each Retry interval. You can use this global parameter to change the behavior so that the driver will retry only one down device per Retry interval. The down devices are retried using a Round Robin algorithm (at the first Retry interval, the first down device is retried, at the next interval, the second down device is tried, etc.). This reduces the elapsed time for the Retry interval and is useful when many enabled devices are down.


Enter one of the following:



Poll one device per Retry interval



Poll all devices at each Retry interval

Default Value




More information

Global parameters.