<Appendix 5. PID Block>
291
IM 01E21A02-03EN
A5.17.1 SHED_OPT
The SHED_OPT setting stipulates the specifications of mode shedding.
Available Setting for
SHED_OPT
Operation Contents
Normal shed, normal return
Sets MODE_BLK.actual to Cas(*1), and leaves MODE_BLK.target unchanged.
Normal shed, no return
Sets both MODE_BLK.Actual and MODE_BLK.Target to Cas (*1).
Shed to Auto, normal return
Sets MODE_BLK.actual to Auto(*2), and leaves MODE_BLK.target unchanged.
Shed to Auto, no return
Sets both MODE_BLK.actual and MODE_BLK.target to Auto(*2).
Shed to Manual, normal
return
Sets MODE_BLK.actual to Man, and leaves MODE_BLK.target unchanged.
Shed to Manual, no return
Sets both MODE_BLK.actual and MODE_BLK.target to Man.
Shed to retained target,
normal return
1. If Cas is specified in MODE_BLK.target, sets MODE_BLK.actual to Cas(*1),
and leaves MODE_BLK.target unchanged.
2. If Cas is not specified in MODE_BLK.target, sets MODE_BLK.actual to
Auto(*2), and leaves MODE_BLK.target unchanged.
Shed to retained target, no
return
1. If Cas is specified in MODE_BLK.target, sets both MODE_BLK.Actual and
MODE_BLK.Target to Cas (*1).
2. If Cas is not specified in MODE_BLK.target, sets MODE_BLK.actual to
Auto(*2), and MODE_BLK.target to Cas.
The modes to which a PID block can transfer are limited to those specified in MODE_BLK.
permitted.
The priority of block modes is as shown below.
For this reason, in fact, (*1) transitions to Cas, Auto, or MAN, whichever is set permitted in
MODE_BLK.Permitted and has the lowest priority level.
FA0105.EPS
Higher priority
level
Lower priority
level
ROut RCas
Cas
Auto
Man
(*2) is only when Auto is set as permitted mode by MODE_BLK.Permitted.
Note: Due to initialization of the cascade connection, if the upstream is a control block, the
transition to the Cas mode occurs in the following sequence:
RCas/ROut -> Auto -> Cas
