GE Baker Hughes Masoneilan SVI FF, Инструкция по установке и эксплуатации

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Transferring Modes
Once the PID and an Output block are scheduled, the PID can command the setpoint. Which
further is translated as a Final_Value to the Transducer block. All blocks must be in service
mode.
RCas Mode
When the positioner is receiving it's position setpoint from a remote computer system, such as
a DCS, then the normal state for the positioner is RCas. In this example, the level control valve,
LV201, is receiving it's signal from a DCS. The Analog Output block (AO) is shown in RCas mode.
RCas mode cannot be manually switched to, it is automatically switched to after being
configured. For example:
Configure the set point of the positioner in DCS to receive remote data, when the
positioner turns to Normal mode, the mode of AO block shows RCas in the
Block Actual
Mode field.
PID in RCas Mode
If an internal PID is used in a cascade where the PID receives a setpoint from a remote
computer system, then the normal state has the PID in RCas mode and the Analog Output
block (AO) is in Cas mode.
The Foundation Fieldbus Application Process specifies the mode handling for inter-operable
function blocks. It also specifies which mode a block must be in when each parameter is
written. SVI FF provides an intelligent, optimized, process for managing configuration and
calibration changes. It does not place blocks into Out Of Service mode unless the parameter
requires OOS. It analyzes the requested changes and then sets the correct mode for each
affected function block.
The Foundation Fieldbus specifies a mechanism for transferring between function block
modes. The user declares a target for the block mode but the actual mode is set by the block
in accordance with rules. The rules allow modes based on the state of input data. Function
blocks comply with the Fieldbus Foundation rules. SVI FF sets target modes for individual
function blocks as required by configuration, calibration, diagnostics and other services. It
sets target modes for a group of function blocks to achieve three operational states of the
positioner: Out of Service, Manual, and Normal.
The PID block remains in Out of Service mode or IMAN when
configuration changes are made. After returning to Normal
operating state, change the PID block mode. If the AO block is left
in Auto mode the valve cannot be moved. Refer to you DCS
manual.
CAUTION