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Manual
00809-0500-4880
Tracking
You can enable the use of output tracking through the control options. You can
set control options in Manual or Out of Service mode only.
The Track Enable control option must be set to True for the track function to
operate. When the Track in Manual control option is set to True, tracking can be
activated and maintained only when the block is in Manual mode. When Track in
Manual is False, you can override the tracking function when the block is in
Manual mode. Activating the track function causes the block's actual mode to
revert to Local Override.
The TRK_VAL parameter specifies the value to be converted and tracked into the
output when the track function is operating. The TRK_SCALE parameter specifies
the range of TRK_VAL.
When the TRK_IN_D parameter is True, and the Track Enable control option is
True, the TRK_VAL input is converted to the appropriate value and output in units
of OUT_SCALE.
Output selection and limiting
Output selection is determined by the mode and the setpoint.
In Automatic, Cascade, or RemoteCascade mode, the PID control equation
computes the output. In Manual or RemoteOutput mode, the you may enter the
output manually. You can limit the output by configuring the OUT_HI_LIM and
OUT_LO_LIM parameters.
Bumpless transfer and setpoint tracking
You can configure the method for tracking the setpoint by configuring the
following control options (CONTROL_OPTS):
•
SP-PV Track in Man: Permits the SP to track the PV when the target mode of
the block is Man.
•
SP-PV Track in LO or IMAN: Permits the SP to track the PV when the actual
mode of the block is Local Override (LO) or Initialization Manual (IMAN).
When one of these options is set, the SP value is set to the PV value while in a
specified mode.
You can select the value that a master controller uses for tracking by configuring
the Use PV for BKCAL_OUT control option. The BKCAL_OUT value tracks the PV
value. BKCAL_IN on a master controller connected to BKCAL_OUT on the PID block
in an open cascade strategy forces its OUT to match BKCAL_IN, thus tracking the
PV from the slave PID block into its cascade input connection (CAS_IN). If the Use
PV for BKCAL_OUT option is not selected, the working setpoint (SP_WRK) is used
for BKCAL_OUT.
You can set control options in Manual or Out of Service mode only. When the
mode is set to Auto, the SP will remain at the last value (it will no longer follow the
PV).
Rosemount OCX8800A
F
Fieldbus
™
OUNDATION
December 2022
179
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