Flex SCADA will automatically detect an input that is jittering (producing an unexpected high and prolonged change in value) and suspend that input so that changes are no longer sent to NMS for processing.

Once a jittering input is detected, any changes in value are no longer processed and the measurement is applied a Jittering quality in NMS. An alarm is raised to notify that the input is jittering. The Jitter State column in the IED Inputs tool updates to indicate the input is jittering.

Once the input is jittering, the system will monitor the rate of change of the input. If it falls below the jitter rate, then the input is deemed to be recovering from jittering. The Jitter State column in the IED Inputs tool updates to indicate the input is recovering. Flex SCADA continues to suspend change of state reporting for the input and a recovery timer is started.

If the inputs rate of change remains normal during the recovery period, then the input is deemed to have returned to normal service. An alarm is raised to indicate that the input has recovered from jittering. The Jitter quality is removed from the measurement in NMS. The input is set to Never Scanned Quality and the IED is force polled to retrieve the latest value for the input. The Jitter State column in the IED Inputs tool updates to indicate the input is in a normal state. Flex SCADA processes any changes of state for the input as normal.

If during the recovery period Flex SCADA detects that the input has started to jitter again, then the recovery period is canceled and the Jitter State column in the IED Inputs tool updates to indicate the input is jittering again.

The SRS rule Jitter Recovery Period defines the length of the jitter recovery period.