GE Baker Hughes Masoneilan SVI FF, Installation And Operation Manual

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Masoneilan SVI FF Instruction Manual =
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115
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Initialization Manual (IMan) The block output is set in response to the back-calculation input
parameter status. When the status indicates there is no path to the
final output element, the control blocks must initialize to provide for
bumpless transfer when the condition clears. A back-calculation out
parameter is supported by all output and control class function
blocks. The setpoint can be maintained or initialized to the process
variable parameter value.
Out of Service (OOS) The block is not being evaluated. The output and setpoint are main-
tained at last value.
When the Transducer block is in OOS mode the output to the valve is
de-energized.
Multiple Modes and States
The Analog Output block (AO) must go to CAS mode to connect to a PID function block in
cascade. To prevent the setpoint signal out of the Analog Output block (AO) from setting the
valve position into the transducer block, the Analog Output block (AO) must go into OOS mode.
Table 22 shows several examples of mode operation.
When a block is in OOS mode its output status is bad. Any connected blocks know and
automatically change their modes. For example, when a PID block sees bad status in BKCAL
IN it goes to IMAN mode for initialization to the downstream block while awaiting the status to
return to good cascade.
Examples of Operational States
Examples of operational states that are combinations of block modes are shown in this
section. A new device or a newly configured device can start up in the out of service (OOS)
state (Table 22).
Table 22 Mode Operation
Operation (AI) PID AO TB
Configure the transducer block (Auto
tuning, travel calibration, etc.)
MAN
Configure transducer block (Chang-
ing position control parameters, etc.)
OOS
Manual valve positioning from Val-
Vue or other human interface.
MAN
Manual valve positioning from a PID
controller human interface.
Manual CAS Auto
PID single loop control Auto Auto CAS Auto
PID cascade loop control (setpoint is
published by another block)
Auto CAS CAS Auto