Device Operational States And Block Modes; Block Modes - GE Baker Hughes Masoneilan SVI FF Installation And Operation Manual

The Heat Exchanger Reference Model segment consists of a Heat Exchanger Host in a control
center with a Foundation Fieldbus trunk connected to two junction boxes. One junction box
has spurs to the flow and temperature control devices and the other connects to the devices
controlling tank level. A power supply with isolation electronics and two terminators
completes the configuration. Configure the ValVue maintenance computer interface cards
(NIFBUS) so as to not interfere with the Heat Exchanger Host.
CAUTION

Device Operational States and Block Modes

SVI FF manages the operational states of the positioner and its embedded PID controller by
controlling the target modes for each of the function blocks. The actual mode of each block
can be different from the target mode. The actual mode is controlled by the block itself in
accordance with mode rules based on the quality of the data and modes of the linked blocks.
A brief summary of modes follows, a thorough discussion of modes is beyond the scope of
this instruction manual. You can refer to the Fieldbus Foundation specification that specifies
the formal rules for mode changing.
Three operational states are set by SVI FF. Out Of Service (OOS) forces all of the blocks to Out
Of Service mode. The outputs remain at the values prior to the state change, but their status
indicates that the block is OOS. All output calculation is suspended. Back calculation values
are passed to other linked blocks to enable initialization. The PID block remains in OOS after
configuration changes unless it is put into one of its allowed modes from the PID dialog box.

Block Modes

All blocks (function/transducer/resource) have operating modes. There are eight modes
defined in the Foundation Fieldbus specification. Not all modes are supported by every block.
For example, the Discrete Input block (DI) supports Auto, Man and OOS. The action of the
modes are described in the following paragraphs. Transfers between modes are managed by
the function blocks in response to manual commands that in turn responded to changes in
the modes of linked blocks and responded to changes in the quality of the parameters that
are transmitted. Control and status options can be set to manage mode changing behavior.
BLOCK_ERR_DESC_1 often can provide information as to why the block is not switched to the
TARGET mode.
© 2019 Baker Hughes, a GE company, LLC. All rights reserved.
Never connect a PC to an operating segment unless it is
configured as a Basic Device. See Figure 50 to view the
configuration options.
Do not cause a short circuit in a working segment while
connecting or disconnecting any device.
Masoneilan SVI FF Instruction Manual
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