Fisher FIELDVUE DVC6200f Instruction Manual page 130

Detailed Setup—PID Function Block
July 2013
Modes
The PID function block supports the following modes:
D Manual (Man)—The block output (OUT [9]) may be set manually.
D Automatic (Auto)—The SP [8] may be set manually and the block algorithm calculates OUT [9].
D Cascade (Cas)—The SP [8] is calculated in another block and is provided to the PID block through the CAS_IN [18]
connection.
D RemoteCascade (RCas)—The SP [8] is provided by a host computer that writes to the RCAS_IN [32] parameter.
D RemoteOutput (ROut)—The OUT [9] is provided by a host computer that writes to the ROUT_IN [33] parameter.
D Local Override (LO)—The track function is active. OUT [9] is set by TRK_VAL [39]. The BLOCK_ERR [6] parameter
shows Local override.
D Initialization Manual (IMan)—The output path is not complete (for example, the cascade-to-slave path might not be
open). In IMan mode, OUT [9] tracks BKCAL_IN [27].
D Out of Service (OOS)—The block is not processed. The OUT [9] status is set to Bad: Out of Service. The BLOCK_ERR
[6] parameter shows Out of service.
You can configure the Man, Auto, Cas, and OOS modes as permitted modes for operator entry.
Mode Handling
Shed Options—RCAS Mode Only
Shed from or climb to a remote mode is determined by the parameter SHED_OPT [34]. A block climbs and sheds
through the same path. For example, if SHED_OPT [34] specifies that a block should shed to Auto, then, if the block
target mode is set to RCas, the block goes through Auto on the way to RCas. You can configure the shed option as
follows:
Shed With Return Options
Remote cascade or remote output connection failure shifts actual mode but keeps trying to restore remote cascade or
remote output (in other words, the remote cascade or remote output target mode stays in effect).
Normal—On failure of a remote connection, the block attempts to attain the highest permitted non‐remote mode
until the remote connection is restored. Cas is the highest permitted non‐remote mode and Auto is is the next highest
permitted non‐remote mode. If Cas or Auto are not available, the block will shed by default to Man.
Retained Target—The retained target mode is the mode the block was in before changing to one of the remote target
modes. On failure of a remote connection, the block attempts to attain the retained target mode.
Auto—On failure of a remote connection, the block attempts to attain Auto, if permitted, until the remote connection
is restored.
Man—On failure of a remote connection, the block sheds to Man until a remote connection is restored.
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Instruction Manual
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