Calculation

Description

The Calculation is a Xentara element which calculates the overall equipment effectiveness on the system. Calculation requires at least one factor and optionally a result.

Calculation Tasks

Sample task

The sample task must be called at regular intervals to sample the values from the factors.

The sample task executes the following processes:

1. reads the input samples for all the assigned factors
2. preforms calculations on each factor
3. updates the intermediate values of the factors
4. calculates the product of all the factors
5. updates the Result Rate

Update task

The update task must be called when a measurement period has finished and starts new period.

The update task executes the following processes:

1. reads the input samples for all the assigned factors
2. preforms calculations on each factor
3. updates the intermediate values of the factors
4. calculates the product of all the factors
5. updates the values of the factors
6. updates the Result Rate
7. resets the intermediate values for all the factors

The period between two updates is defined as sampling period.

Xentara Downtime

Apart from the input factor measurements on sample task, each factor evaluates also the duration of time that Xentara is off-line.

Downtime Evaluation

In case Xentara is off-line an unspecified amount of time for any reason, when Xentara is on line again, the Xentara downtime is calculated and added as downtime for the calculations.

Depends on how long the Xentara was off-line, the quality and the error message updated accordingly.

• If the total Xentara Downtime is less than 2% of the total sampling period, the quality drops to acceptable.
• If the total Xentara Downtime exceeds 2% of the total sampling period, the quality drops to unreliable.

For example, if the input values of the factor is always good with no error for the total sampling period, we can have two different cases:

1. With total sampling period 480 minutes (8 hours) and there Xentara was off-line for 5 minutes for all the measured period, the Xentara downtime is less than 2%, the quality drops to acceptable.
2. With total sampling period 480 minutes (8 hours) with Xentara Downtime 20 minutes for all the measured period, the Xentara downtime exceeds 2%, the quality drops to unreliable.

On the update task, the quality and the error of the individual factors is updated accordingly.

Accessing Calculation

See also

Accessing Xentara Elements in the Xentara user manual

In addition to the standard members of Xentara I/O points, Calculation has the following attributes:

Attributes

sampleTime	The timestamp containing the last time the sample task called.
updateTime	The timestamp containing the last time the update task called.

Calculation have the following tasks:

Tasks

sample	The sample task preforms a sample from the input values and calculates the intermediate values.
update	The update task preforms a sample, calculates and updates the values and resets the intermediate values