Calculations

Allows the execution of JavaScript functions based on the value of points or SQL queries to the database. This functionality must be enabled in your license.

Screenshot

Configuration

This screen allows defining calculations for points whose Type has been set to Calculation

• Select the display to which the calculated point belongs from the dropdown list located in the upper left area of the window
• The list of points will update according to the selected display
• Fill in the following fields

  Field	Description
  Function	Function to be used in this calculation
  Period (secs)	Period in seconds between calculation executions
  Data source	Source data for performing the calculation

• Click “Save”.

Data source format

Enter text in JSON format containing an array of key:value objects with the following format:

[
  {"key":"value_1"},
  {"key":"value_2"},
  {"key":"value_3"}
]

You must specify as many {“key”:“value”} pairs as the parameters accepted by the selected function.

Data source examples

Taking data from other points by pointId

The Ids of the points whose values will be passed to the selected function are specified. Example:

**
[
  {"pointId":"2000"},
  {"pointId":"2001"},
  {"pointId":"2002"}
]

Since three pointIds have been specified, the selected function must accept three arguments: function(a,b,c) { … }

Taking data from other points by pointName

The Names and Sub-names of the points whose values will be passed to the selected function are specified. Example:

[
  {"pointName":"TANK 1:LEVEL"},
  {"pointName":"TANK 2:LEVEL"},
  {"pointName":"TANK 3:LEVEL"},
  {"pointName":"TANK 4:LEVEL"}
]

Since four pointNames have been specified, the selected function must accept four arguments: function(a,b,c,d) { … }

Taking data from SQL queries to the database

SQL statements whose results will be passed to the selected function are specified. Example:

[
  {"sqlQuery":"SELECT colName FROM table WHERE colId=10"},
  {"sqlQuery":"SELECT colName FROM table WHERE colId=11"},
  {"sqlQuery":"SELECT colName FROM table WHERE colId=12"}
]

Combinations of the previous examples

The pointId, pointName and sqlQuery types can be combined. Example:

[
  {"pointName":"PUMP 1:STATUS"},
  {"pointId"  :"1002"},
  {"pointId"  :"1013"},
  {"pointId"  :"1024"},
  {"pointName":"TANK 3:LEVEL"}
]