Function Blocks
Function Block Reference Guide
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2.55 ROC Function Block,
continued
Example
Figure 2-57 illustriates various responses for the Rate Of Change Function Block. You can also use the
ROC block to alarm if Rate exceeds the Preset Setpoint Limit.
HI rate SP (INC)
HI RC = ON
HI rate SP (INC)
HI RC = OFF
HI rate SP (DEC)
HI RC = ON
HI rate SP (DEC)
HI RC = OFF
LO rate SP (INC)
LO RC = OFF
LO rate SP (INC)
LO RC = ON
LO rate SP (DEC)
LO RC = OFF
LO rate SP (DEC)
LO RC = ON
High Rate SP (INC )
LOW Rate SP (INC)
HI rate SP (INC)
HI RC = OFF
HI rate SP (DEC)
High/Low Rate SP (Both)
LO rate SP (DEC)
High Rate SP (DEC )
LOW Rate SP (DEC)
LO rate SP (INC)
LO RC = OFF
HI rate SP (INC)
HI RC = OFF
HI rate SP (DEC)
LO rate SP (DEC)
LO rate SP (INC)
LO RC = ON
Figure 2-57 ROC Function Block Responses
Place in Alarm group for
Alarm detection/annunciation
Place in Overview Display
group to view rate
Signal Tags
Figure 2-58 ROC Function Block Example