2 loop error indicators – Honeywell VRX180 User Manual

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Diagnostic and error messages

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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

(Failsafe)

Flashing
symbols

Action needed

(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

Mode = Suspend Auto*

Output = Failsafe

SP2
AUTO
MAN**
PV

Select SP1 then SP2
Select Manual then
Auto

Manual & SP2

SP2 & PV Failure

Working SP = SP1

Mode = Manual

Output = Last value

SP2
PV

Select SP1 then SP2

Auto & SP1/SP2

PV Failure or

Force Remote Manual
Failure or

Output Tracking
Failure or

Feedforward Failure

Mode = Suspend Auto*

Output = Failsafe

AUTO
MAN**
PV

Select Manual then
Auto

Manual & SP1/SP2

PV Failure

Mode = Manual

Output = Last Value

PV None

required

Auto & SP1/SP2

See below***

Mode = Suspend Auto*
Output = Back Calc. Value

AUTO
MAN

None required

Auto & SP1/SP2

Force Remote Manual

Mode = Suspend Auto*
Output = Tracking value

AUTO None

required

*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.

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