Filter
Top Products
Reference Manual
IP2030/RM, Rev AA
Section 4: Getting started
June 2014
Section 4: Getting started90
The calculation assumes that liquid continues to enter the well or tank at the rate just prior to
the relay energizing (pump starting).
The control unit continuously calculates the rate of change, sampling a new control unit PV
every 5 seconds (as described in Section “Rate of Change mode relay” on page 83).
Over the next 9 pump starts, a further 9 change of RoC values are stored such that the control
unit can then calculate an average value in change of RoC. This average value, “RoC100” is then
taken as being equivalent to the pump operating at 100% efficiency. A value of 100% is then
stored in D86*.
Each subsequent pump start, and change in RoC thereafter, is used in a rolling average
calculation for a new average value in change of RoC, RoCnew, which is then compared to the
previous value “RoC100” and a new PE percentage value calculated using:
PE % = (RoCnew / RoC100) * 100
If the resulting PE is greater than 100%, the RoC100 is updated to the new value and the PE is
re-stated as 100% based on this new value.
If the resulting PE is less than 100%, then the PE is calculated as above and stored in D86*
If the PE is below the limit set (P495), the PE alarm condition is true. To indicate an alarm by
Relay or Current Output, a method must be selected (see “Set-up alarms” on page 91).
Note
The alarm condition is automatically cleared if the calculated PE rises above the limit
(P495) by 5% or more
Pumped volume totalizing
(Totalizer Option – see Table 4-5 on page 73 for a full list of auxiliary relay functions)
This function is for calculating the total throughput in a contents volume application.
The control unit monitors the change in volume when no pumps are running i.e. when any
Assist or Standby mode relay is de-energized. It calculates the rate of change (RoC) of the
control unit PV (D800) every five seconds and then converts it to a rate of change per minute for
displaying as parameter D809.
When a pump is turned on, the control unit assumes that the rate of inflow remains the same as
it was just before starting the pumps. The RoC value (D809) is frozen while the pumps are on i.e.
when any Assist or Standby mode relay is energized.
To totalize pumped volume, the control unit PV (D800) must be in volume units so that the RoC
value (D809) is in units of volume per minute. The control unit integrates this volume every
second and increments the totalizer for every integer unit.
If the RoC value (D809) is 12 m
3
per minute and the Total factor parameter (P530) is set to
1.0 (m
3
), the Totalizer count (D828) increments every five seconds (
1
/
12
th of a minute).
Note
The Totalizer Wizard can be used to set-up pumped volume totalizing.