DSUB calculates the difference between daily values of an existing variable, without rollover.  This will return negative results when they occur. 

SYNTAX:

DSUB(Cx)
where :
Cx is a daily conditional variable x

DSUB calculates the difference between daily values of the variable defined by Cx.  It will then display the results as a new variable.  If the previous day's values is not present, the function searches back up to 7 days to fine a value for Cx to determine the difference.  If no previous entry is found within those 7 days, a value of zero (0) is assumed for the difference calculation.

This function will produce negative values if the current value is less than the previous value.  When calculating changes in values from a device on which rollover occurs (i.e., a runtime meter) you may consider using the DDIF function.

NOTES:

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

EXAMPLES:

V82 = DSUB(V70)

Variable 82 will contain a value which is the difference between today's value for variable 70 and yesterday's value for variable 70, as demonstrated below:

As we see above: 2.6758-2.4533 = 0.2225 which is rounded down to 0.22 because V82 is set to 2 decimal places.