Time estimation for store-and-forward data

The actual time taken to forward store-and-forward snapshots depends on the amount of data accumulated and the bandwidth limit. HCAL typically waits for about 30 seconds to attempt the forwarding process after reconnection. It may need to wait for a longer time if the Historian is busy.

To simplify the calculation, the following is assumed:

• HCAL can start forwarding immediately without interruption

• The bandwidth is 30% above the data rate before disconnection

The time taken to forward is as follows:

TimeForwarding = TimeInStoreforward * RatioForwardingDataSize / 0.3

Where RatioForwardingDataSize = Forwarding data Size / Streaming data size

For example, the date rate is 1 Mbps and the bandwidth is 1.3 Mbps. Assume you have simple replication for analog tags and store-and-forward data has been accumulating for 1 hour.

RatioForwardingDataSize = 8 / 34 = 0.235

TimeForwarding = 60 (minutes) * 0.235 / 0.3 = 47 minutes