DDIF Today - Yesterday = Todays Flow

Calculates the difference between daily values of an existing variable, VX.

SYNTAX:

DDIF(VX, Optional Rollover)

NOTES:

If the previous day's value is not present, the program searches 32 previous days to find a value for VX to determine the difference.  If no previous entry is found within thirty two (32) days, a value of zero (0) is assumed for difference calculation.  The optional Rollover specifies the Rollover point.  If the optional parameter is not specified, the system assumes the rollover point is at the next power of 10.  The system assumes rollover occurs if today's value is less than the last previous value and makes the appropriate entry.

EXAMPLES:

V53 = DDIF(V52)

Calculates daily difference of values stored in variable 52, and records them as variable 53.  Consider the following example illustrating rollover and lookback.

 

V55 = DDIF(V52,990)

Calculates daily difference of values stored in variable 55, and records them as variable 53.  Meter rollsover at 990. Consider the following example illustrating rollover and lookback.

NOTE:  The DDIF function can be used with Daily Detail variables (Hourly, 15 minute...) to calculate a daily result.  The DDIF function will use the last Daily Detail reading of the day minus the last Daily Detail reading from yesterday.

 V57 = DDIF(V56)       'V56 is an hourly entry, V57 would calculate 15.