Honeywell HC900 - Electrical Considerations

Function Blocks
AI Function Block
Revision 11 HC900 Hybrid Control Designer Function Block Reference Guide 45
2/07
Failsafe rules
If the controller is unable to access the physical channel or the sensor is faulty, and:
• If Failsafe is “Use Value” Then OUT = Configured Failsafe value
• If Failsafe is enabled and downscale Then OUT = Range Lo (linear)
Low Range Value of input type (T/C and RTD)
• If Failsafe is enabled and upscale Then OUT = Range Hi (linear)
High Range Value of input type (T/C and RTD)