Worked examples of the MP-5 calculator:
The information in the article refers to:
Monitor-Pro MP-5
Applies to:
| Product: | MP-5 |
| Reported Version: | MP5.0.1 |
| Applies to: | All MP-5 versions |
| Area of effect | Admin tool |
Overview
Worked examples of the MP-5 calculator
Details
Generic calculations
Worked example 1: Static water level
This is a very simple calculation to calculate the head of liquid in a borehole.
Preparation
Your data needs to be stored as a variable, in this case Liquid Level AOD (m). You will need to check that the destination variable is available, or create it.
Likewise, all data has to have a source assigned to it. This is your choice but as calculated data has no "real" source, we suggest that you create one called "Calculated", "Derived" or similar.
Creating the calculation
First go to tools... calculations... calculations, and double click on "add new generic calculation".
1. On the Overview tab, give your calculation a name and tick "active"
2. On the calculation tab, start by selecting "Variable" from the drop-down list.
3. Find your datum variable and double click on it. It will appear on the right pane. Next, place a "-" sign and double click your dip variable. Press the "Check Syntax" button.
4. Assign the destination (result) variable and source.
5. Set interpolation options
Interpolation needs some explanation. By default the calculator will only
calculate records that have the same date/time stamp. It would be
dangerous for it to make any other assumptions. However, in this example,
the datum will probably have been measured months ago. Therefore it has
been set to "previous". Now, for each sample point dip reading, the
calculator will track back to the previous datum recorded at this sample point,
and use this reading. Other options are:
- Next
- Nearest (backwards or forwards)
- Presume 0 (some systems require a 0 to be stored where no corresponding
value has been recorded.
- Presume 1 (as above)
- Always use previous (forces the use of previous result, even when there
is a corresponding reading at the same date/time)
- Always use next (as above).
6. Choose the sample points that the calculation applies to.
7. Set Periodicity
Periodicity is the times of day, days of week etc. that the calculator will run
on. It is normally set to "always" - i.e. all dates & times.
However, there are examples where you will need to be more specific - maybe
recording pollution levels only in the rush hour, or energy use in a factory
Monday to Friday.
8. Recalculate
For accuracy and efficiency, all data already in your database has been marked
"don't calculate me". Therefore, calculations when created will only act
on new data. If you need to apply the calculation retrospectively (or have
changed the calculation and want to recalculate historical data), choose the
recalculate tab and select those sample points to be marked "calculate me" next
time the calculator runs (next import of data).
Worked example 2: Weight of rubbish
A variation of example 1.
Worked example 3: % Methane change
This example differs from 1 & 2 in that it is subtracting a variable from itself
and creating a % difference. This is useful as subsequently a threshold
level can be set on the difference. A similar calculation is often
applied to pumps & flow meters to determine volumes.
Key here is interpolation. In this case, of course you have a matching record of the same date & time (the first most recent reading). The previous interpolation gets overruled by this match. Therefore you need to force previous as below...
