Honeywell VRX180 user manual Loop Error Indicators, Abnormal Loop Conditions And Indicators

Diagnostic and error messages

9.2 Loop Error Indicators

When a loop's PV, SP2, or other parameter fails, the loop switches to its default/failsafe condition, indicated by certain display symbols flashing. To return the loop to its desired condition, correct the failure. Then, if the loop's LATCHING is NO, the loop will return to normal automatically. If LATCHING is YES, also perform the action needed to return the loop to normal.

Table 9-3 Abnormal Loop Conditions And Indicators

Desired Condition		Abnormal Condition		Default condition		Flashing	Action needed
				(Failsafe)		symbols	(if LATCHING = YES)
Auto & SP2		SP2 Failure		Working SP=SP1		SP2	Select SP1 then SP2
Manual & SP2	SP2 Failure		Working SP=SP1		SP2		Select SP1 then SP2
Auto & SP2		SP2 & PV Failure		Working SP=SP1		SP2	Select SP1 then SP2
				Mode = Suspend Auto*		AUTO	Select Manual then
						MAN**	Auto
				Output = Failsafe		PV
Manual & SP2	SP2 & PV Failure		Working SP = SP1			SP2	Select SP1 then SP2
				Mode = Manual		PV
				Output = Last value
Auto & SP1/SP2		PV Failure or		Mode = Suspend Auto*		AUTO	Select Manual then
		Force Remote Manual		Output = Failsafe		MAN**	Auto
						PV
		Failure or
		Output Tracking
		Failure or
		Feedforward Failure
Manual & SP1/SP2		PV Failure		Mode = Manual		PV	None required
				Output = Last Value
Auto & SP1/SP2	See below***			Mode = Suspend Auto*		AUTO	None required
				Output = Back Calc. Value		MAN
Auto & SP1/SP2		Force Remote Manual		Mode = Suspend Auto*		AUTO	None required
				Output = Tracking value

*Due to the abnormal condition the loop cannot be in Auto and therefore is in a temporary mode which forces the output as indicated.

**If loop feedback is not connected to an AO, or if loop type is ON/OFF, then MAN will be steady, not flashing.

***Status from a downstream function block indicates that there is no path to final output element. For example, the secondary control loop of cascade configuration was changed to manual mode.

254 Video Recorder – User Manual