Flow Accumulator

Site Summary component >Flow Accum. button

When flow is measured at a gate or meter, the accumulated volume is stored locally on the RTU, and also in the host database. The accumulated value is also accumulated in a separate tag on the host database.

If the RTU is replaced due to failure or maintenance, you can write the volume stored on the host to the RTU.

General Tab

Field	Description	Tag
Current Volume for Season (ML)	The flow volume accumulated on the host system since last reset. The tag name is FLOW_ACU_TOTAL.	FLOW_ACU_TOTAL
Total Volume Displayed on LCD (ML)	Volume as displayed on the site pedestal. This is calculated as the sum of the two tags on the Advanced tab: Volume Before Reset + Volume Since Reset

Synchronising the Accumulators

Click the Synchronise button if you need to synchronise the local value displayed on the pedestal screen with the correct accumulated volume stored in the host database. For example, you might do this if you replace the RTU.

This is what the process does:

• Writes the value of the Current Volume for Season (FLOW_ACU_TOTAL) from the host into the Volume Before Reset tag on the RTU
• Sets the Volume Since Reset tag value to zero.

Advanced Tab

Field	Description	Tag
Volume Before Reset (ML)	Sets the overall volume in the host accumulator at the last reset of the local accumulator. This is written to a local tag whenever the accumulators are synchronised.	FLOW_ACU_BR
Volume Since Reset (ML)	Volume accumulated since the local accumulator was last reset	FLOW_ACU_SR

Resetting the Volume Since Reset

You would typically use this function to set the locally displayed volume to zero, regardless of the accumulated value on the host. For example:

• For a FlumeGate, you could set both the FLOW_ACU_BR and the FLOW_ACU_SR to zero.
• For a gate or meter with an integrated flowmeter, the FLOW_ACU_SR value will be the same as the accumulated value stored in the meter, so to zero the local display you should set the FLOW_ACU_BR to the the negative of that value.

Click the Reset button to set the Volume Since Reset to zero. The Volume Before Reset is not changed. You can change the Volume Before Reset value with the setpoint button.

Note that this will not interfere with the correct accumulation of volume at the host, but it will make the volume shown on the LCD inconsistent with the value stored on the host in the Current Volume for Season (FLOW_ACU_TOTAL) tag.