Device Variables - Fisher FIELDVUEDVC6200f Instruction Manual

DVC6200f Digital Valve Controller
Viewing Device Variables and Diagnostics
February 2017
•VST State (VST_STATE [125.1])
•VST Result (VST_RESULT [121])
•Test Abnormal Cause (VST_DETAILED_CODE[126])

Device Variables

TB > Device Variables
Field Communicator
TB Block Modes
Block Mode: Target (TARGET [5.1]) is the mode requested by the user or host system. Generally, only one mode is
allowed to be set, and it must be a permitted mode as defined by the permitted attribute of the mode parameter.
Additionally, all cascade targets (Cas, Rcas) must have AUTO set.
Block Mode: Actual (ACTUAL [5.2]) is the current mode of the block. The actual mode may differ from the target mode
due to operating conditions of the block.
Note
Block Mode:Actual drops the AUTO bit for the cascade targets. For example, target mode might have Cas and Auto set, but actual
mode will only have Cas set.
Block Mode: Permitted (PERMITTED [5.3]) defines the modes allowed for the block. This is set by the user or host
system but is restricted by the instrument to modes supported by the instrument for the particular block. Any change
request to the Target or Normal attribute is checked against the permitted attribute to ensure the requested mode is
permitted. When setting the Permitted mode, there is no check against any of the other attributes (Normal or Target
modes). Therefore, the normal or target mode attributes may have a value that is not permitted because the
permitted attribute was modified after the Normal or Target mode was set. This will have no effect on the instrument
until the user attempts to modify the Target or Normal mode. At this time these attributes are tested against the
Permitted modes, thus the user cannot change the Normal or Target modes to what was formerly permitted.
Block Mode: Normal (NORMAL [5.4]) is the mode the block should be in during normal operating conditions. The
normal mode is set by the user or host system and can only be set to a permitted mode (see permitted mode). The
user or host system can compare the actual mode to the normal mode and, based on the results, determine if the
block is operating normally.
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Instruction Manual
D103412X012