Mode Shedding On Computer Failure - GE FVP110 Maintenance Manual

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Mode Shedding on Computer Failure

Mode shedding occurs in accordance with the SHED_OPT setting when:
❑
(1) the data status of RCAS_IN, which is the setting received from a computer as
the setpoint SP, falls to Bad while the PID block is running in the RCas (remote
cascade) mode,
or
❑
(2) the data status of ROUT_IN, which is the setting received from a computer as
the remote output signal, falls to Bad while the PID block is running in the ROut
(remote output) mode
Available Setting
for SHED_OPT
Normal shed, normal return
Normal shed, no return
Shed to Auto, normal return
Shed to Auto, no return
Shed to Manual, normal return Sets MODE_BLK.actual to Man, and leaves MODE_BLK.target unchanged.
Shed to Manual, no return
Shed to retained target,
normal return
Shed to retained target, no
return
Table 51 STATUS_OPTS of PID Block
Sets MODE_BLK.actual to Cas(*1), and leaves MODE_BLK.target unchanged.
Sets both MODE_BLK.actual and MODE_BLK.target to Cas(*1).
Sets MODE_BLK.actual to Auto(*2), and leaves MODE_BLK.target unchanged.
Sets both MODE_BLK.actual and MODE_BLK.target to Auto(*2).
Sets both MODE_BLK.actual and MODE_BLK.target to Man.
If Cas is set in MODE_BLK.target, - sets MODE_BLK.actual to Cas(*1)
and
❑ leaves MODE_BLK.target unchanged.
If Cas is not set in MODE_BLK.target,
❑ sets MODE_BLK.actual to Auto(*2)
and
❑ leaves MODE_BLK.target unchanged.
If Cas is set in MODE_BLK.target, sets:
❑ MODE_BLK.actual to Cas, and
❑ MODE_BLK.target to Cas(*1), too.
If Cas is not set in MODE_BLK.target, sets:
❑ MODE_BLK.actual to Auto(*2), and
❑ MODE_BLK.target to Cas.
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FVP 110 Fieldbus Valve Positioner Manual
Actions upon Computer Failure