Mode Shedding On Computer Failure; Shed_Opt Of Ao Block - GE FVP110 Maintenance Manual

Mode Shedding on Computer

Mode Shedding on Computer Failure

When the data status of RCAS_IN falls to Bad while the block is running in RCas
(remote cascade) mode, mode shedding occurs in accordance with the setting in
SHED_OPT. Table 39 shows the available selections for the AO block SHED_OPT
setting.
Bit Available Setting for
SHED_OPT
Normal shed, normal return
1
Normal shed, no return
2
Shed to Auto, normal return
3
Shed to Auto, no return
4
Shed to Manual, normal return Sets MODE_BLK.actual to Man, and leaves MODE_BLK.target
5
6 Shed to Manual, no return
Shed to retained target,
normal return
7
Shed to retained target, No
return
8
Table 39 SHED_OPT of AO 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).
unchanged.
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
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, too.
If Cas is not set in MODE_BLK.target, sets:
❑ MODE_BLK.actual to Auto(*2),
and
❑ MODE_BLK.target to Cas.
137
Actions upon Computer Failure
AO Function Block