Bkcal_In - Emerson Oxymitter 5000 Instruction Manual

Oxymitter 5000
Table E-1. PID Function Block
System Parameters
Parameter Number
ACK_OPTION
ALARM_HYS
ALARM_SUM
ALERT_KEY
ALG_TYPE
BAL_TIME
BIAS
BKCAL_HYS

BKCAL_IN

BKCAL_OUT
E-2
The block supports two forms of the PID equation: Standard and Series. You
can choose the appropriate equation using the FORM parameter. The
Standard ISA PID equation is the default selection.
Series Out = GAIN
Where
GAIN: proportional gain value
r: Integral action time constant (RESET parameter) in seconds
t
s: laplac e operator
d: derivative action time constant (RATE parameter)
a
:
F: feedforward control contribution from the feedforward input (FF_VAL parameter)
e: error between setpoint and process variable
To further customize the block for use in your application, you can configure
filtering, feedforward inputs, tracking inputs, setpoint and output limiting, PID
equation structures, and block output action. Table E-1 lists the PID block
parameters and their descriptions, units of measure, and index numbers, and
Figure E-1 illustrates the internal components of the PID function block.
Index
Units
46 None
47 Percent
45 None
04 None
74 None
25 Seconds
66 EU of OUT_SCALE
30 Percent
27 EU of OUT_SCALE
31 EU of PV_SCALE
x x
Standard Out = GAIN
x x
e
fixed smoothing factor of 0.1 applied to RATE
Description
Used to set auto acknowledgment of alarms.
The amount the alarm value must return to within the alarm limit before the
associated active alarm condition clears.
The summary alarm is used for all process alarms in the block. The cause of
the alert is entered in the subcode field. The first alert to become active will
set the Active status in the Status parameter. As soon as the Unreported
status is cleared by the alert reporting task, another block alert may be
reported without clearing the Active status, if the subcode has changed.
The identification number of the plant unit. This information may be used in
the host for sorting alarms, etc.
Selects filtering algorithm as Backward or Bilinear.
The specified time for the internal working value of bias to return to the
operator set bias. Also used to specify the time constant at which the integral
term will move to obtain balance when the output is limited and the mode is
AUTO, CAS, or RCAS.
The bias value used to calculate output for a PD type controller.
The amount the output value must change away from the its output limit
before limit status is turned off.
The analog input value and status from another block's BKCAL_OUT output
that is used for backward output tracking for bumpless transfer and to pass
limit status.
The value and status required by the BKCAL_IN input of another block to
prevent reset windup and to provide bumpless transfer of closed loop control.
Instruction Manual
IM-106-350, Rev 2.2
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July 2008
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