Understand the Accumulator's Input Rollover volume

Each accumulator device has a point at which it reaches its maximum limit and resets to zero to start again. This limit should be larger than the Maximum Reasonable Flow Rate (vol/h). This change in the value (for example, going from 10,000 to 200) needs to be accounted for. When a counter value was previously near its rollover value and is now near (or at) zero, we assume a rollover. The device's maximum value was reached and then reset to zero.

When the input counter reaches the Input Rollover, the counter starts over again at zero (so the counter is always less than or equal to the Input Rollover).

There is a configurable rollover field in both the rate and accumulator records. For Virtual Flow Computer (VFC) calculations, the accumulator record’s Input Rollover will be used. The rate record's Roll-over value is still used for the rate record’s own internal processing.

The number configured for the Input Rollover field on the accumulator record should match the Roll-over value configured on the rate record associated with the accumulator. There are three possible scenarios for this:

• If the rate is using a Hardware Rollover (that is, it is configured as a Pulse-Input Rate) it should match the number configured in the Roll-over value field of the rate record.

• If the rate is using a Software Rollover (that is, the Enable Software Accumulator checkbox has been selected) the Input Rollover on the accumulator should be configured to use the same value as the Software Accumulator. Currently, the Software Accumulator used by the rate record defaults to a value of 1,000,000.

• If the rate has both a Roll-over value entry and an Enable Software Accumulator selected, the Software Rollover value should be used for the accumulator’s Input Rollover value.