Rate Limit function block parameters

The following table lists the system parameters for the Rate Limit function block:

Table: Rate Limit function block system parameters
Parameter	Units	Description
DECR_LIMITED	None	When 1, indicates that OUT is not equal to IN due to a decreasing rate of change exceeding (being less than) DECREASE_MAX. Otherwise, the value is 0.
DECREASE_MAX	EU of IN per TIME_UNITS	The maximum decreasing rate of change allowed for OUT. DECREASE_MAX must be a negative number.
ENABLE	None	The discrete input that activates rate limiting.
IN	Determined by source	The analog input value and status.
INCR_LIMITED	None	When 1, indicates that OUT is not equal to IN due to an increasing rate of change exceeding (being greater than) INCREASE_MAX. Otherwise, the value is 0.
INCREASE_MAX	EU of IN per TIME_UNITS	The maximum increasing rate of change allowed for OUT. INCREASE_MAX must be a positive number.
LIMITED	None	When 1, indicates that OUT is not equal to IN due to an excessive rate of change. Is the logical OR of DECR_LIMITED and INCR_LIMITED. Otherwise, the value is 0.
OUT	EU of IN	The analog output value and status.
ROC	EU of IN per TIME_UNITS	The filtered rate of change of the IN parameter. ROC is an indication that is independent of the scan-to-scan rate of change used by the block algorithm to determine OUT.
TIMECONST	Seconds	The time constant of the first order filter applied to the scan-to-scan rate of change calculation for the ROC parameter.
TIME_UNITS	Selectable time unit - seconds, minutes, hours, or days	Determines the time units for the ROC parameter. Also used to convert INCREASE_MAX and DECREASE_MAX to units of EU/sec.

Note

Default values and data type information for the parameters are available by expanding the Parameter View window.