Amount

This is a function of the LagCorrection class.

Description

This function is used to calculate a data-driven lag time based on a counter.

Use this if the source of your lag is being counted or totalised instead of being measured as a rate. Note that in many industrial applications, field-based counters or totalisers are more accurate than performing calculations on rates.

For example, you might have a conveyor system measuring how many meters you've moved. If Sensor X is 50m away from Sensor Y, you can calculate the time lag between Y and X by going backwards and finding out how long it took for 50m of conveyor to pass.

Parameters

ParameterTypeMeaning
serverARDI API ServerThe ARDI server to query
querystringThe AQL Query to send
amountfloatThe amount to lag the time by
origindatetimeThe ending/reference time (default=now)
secondsintThe maximum number of seconds to search (default=1 day)
expectedintThe average amount of time in normal operation (default=10 minutes)

Returns

The number of seconds of lag between the origin time and when amount has been counted.

Notes and Behaviour

The expected time should be the maximum amount of lag you'd expect to have during normal operation (ie. if your machines didn't stop in the mean-time).

The seconds time should be the maximum amount of lag you're willing to search for.

Example

    srv = ardiapi.Server('demo.optrix.com.au/s/pl')
 
    lc = samplestream.LagCorrection()
    diff = lc.Amount(srv,"'Paint Line' ASSET 'Distance' PROPERTY VALUES",25)
 
    print("Roller 2 Lag Correction - " + str(dt))