165
STATUS_OPTS
PID Function Block
STATUS_OPTS
Table 50 shows the options in STATUS_OPTS.
Auto Fallback
Auto fallback is when a PID block changes mode from Cas to Auto and continues
automatic PID control with the user-set setpoint. To enable the auto fallback action to
take place:
❑ The Target to next permitted mode if BAD CAS IN option must be preset to true
in STATUS_OPTS.
AND
❑ Auto must be preset in MODE_BLK.permitted.
If the above settings are made, auto fallback takes place automatically when the
following condition is met:
❑ CAS_IN.status (data status of cascade setpoint) is Bad except when the control
action bypass is on.
Table 50 STATUS_OPTS of PID Block
Bit Options in CONTROL_OPTS Description
0
IFS if BAD IN Sets the sub-status component of OUT.status to IFS if IN.status
is Bad except when PID control bypass is on.
1
IFS if BAD CAS IN Sets the sub-status component of OUT.status to IFS if
CAS_IN.status is Bad.
2
Use Uncertain as Good Does not regard IN as being in Bad status when IN.status is
Uncertain (to prevent mode transitions from being affected
when it is Uncertain).
5
Target to Manual if BAD IN Automatically changes the value of MODE_BLK.target to Man
when IN falls to Bad status.
9
Target to next permitted mode
if BAD CAS IN
Automatically changes the value of MODE_BLK.target to Auto
(or to Man if Auto is not set in Permitted) when CAS_IN falls to
Bad status.
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