The following are things to consider when configuring write
confirmation:
- Each protocol behaves differently. The scan times vary based on each
of the following, the impact of which varies based on the selected protocol.
- The number of logical devices on a specific physical device. Note
that different physical devices can have different scan times.
- The total number of physical and logical devices configured on
the controller
or EIOC
affects communication time.
- The frequency of output changes. Outputs are typically only
driven on demand which increases the time of a scan that includes a write.
- With the 61850 protocol, the configuration of an SBO or SBOw
output affects communication time. In this case, two messages are required to
drive the output which increases the total time needed.
- All communications occur over Ethernet which can have time delays
causing a retransmission of the packet. Any timeouts associated with retries
impacts the scan time. Confirmation times must allow for these normal retry
delays.
- Do not make the write confirmation time unrealistic for your
scenario.