Honeywell HC900 Reference Manual page 64

Function Blocks
ALM Alarm Function Block
[(PV-CV)>SP] High Deviation Alarm
OUT = ON
•
OUT = OFF
•
[(CV-PV)>SP] Low Deviation Alarm
OUT = ON
•
OUT = OFF
•
⏐PV-CV⏐>SP
OUT = ON
•
OUT = OFF
•
Inputs
PV = Process Variable
CV = Compare Value
RSP = Remote Setpoint
DISABLE = On disables alarm action.
Output
OUT = Output
Block properties
50
If the PV input minus the CV input is greater than the Local Setpoint
If the PV input minus the CV input is less than the Local Setpoint minus Hysteresis
If the CV input minus the PV input is greater than the local Setpoint
If the CV input minus the PV input is less than the Local Setpoint minus Hysteresis
Band Deviation Alarm
If the absolute value of (PV–CV) is greater than the Local Setpoint
If the absolute value of (PV–CV) is less than the Local Setpoint minus Hysteresis
HC900 Hybrid Control Designer Function Block Reference Guide Revision 11
2/07