Emerson Rosemount OCX8800 Instruction Manual page 167

Instruction Manual
IM-106-880C, OI
The MODE parameter is a switch that indicates the target and actual mode of operation. Mode
selection has a large impact on the operation of the PID block:
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Abrupt changes in the quality of the input signal can result in unexpected loop behavior. To
prevent the output from changing abruptly and upsetting the process, select the SP-PV Track in
Man I/O option. This option automatically sets the loop to Manual if a Bad input status is
detected. While in manual mode, the operator can manage control manually until a Good input
status is reestablished.
Application
Information
Manual mode allows the operator to set the value of the loop output signal directly.
Automatic mode allows the operator to select a setpoint for automatic correction of
error using the GAIN, RESET, and RATE tuning values.
Cascade and Remote Cascade modes use a setpoint from another block in a cascaded
configuration.
Remote Out mode is similar to Manual mode except that the block output is supplied by
an external program rather than by the operator.
Initialization Manual is a non-target mode used with cascade configurations while
transitioning from manual operation to automatic operation.
Local Override is a non-target mode that instructs the block to revert to Local Override
when the tracking or fail-safe control options are activated.
Out of Service mode disables the block for maintenance.
Section 7: Foundation
Fieldbus
April 2017
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