Emerson Oxymitter 5000, Instruction Manual

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Oxymitter 5000
E-2
Instruction Manual
IM-106-350, Rev 2.2
July 2008
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.
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.
Table E-1. PID Function Block
System Parameters
Standard Out = GAIN e
x x
1
r
s 1
+
d
s
d
s 1
+
1 + F
+
Series Out = GAIN e
x x
1
1
r
s
+
d
s 1
x
+
d
s 1
+
F
+
Where
GAIN: proportional gain value
r: Integral action time constant (RESET parameter) in seconds
s: laplac e operator
d: derivative action time constant (RATE parameter)
fixed smoothing factor of 0.1 applied to RATE
F: feedforward control contribution from the feedforward input (FF_VAL parameter)
e: error between setpoint and process variable
+
t t
t
t t
+
a
t
a :
t
38730128
Parameter
Index
Number Units Description
ACK_OPTION 46 None Used to set auto acknowledgment of alarms.
ALARM_HYS 47 Percent The amount the alarm value must return to within the alarm limit before the
associated active alarm condition clears.
ALARM_SUM 45 None 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.
ALERT_KEY 04 None The identification number of the plant unit. This information may be used in
the host for sorting alarms, etc.
ALG_TYPE 74 None Selects filtering algorithm as Backward or Bilinear.
BAL_TIME 25 Seconds 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.
BIAS 66 EU of OUT_SCALE The bias value used to calculate output for a PD type controller.
BKCAL_HYS 30 Percent The amount the output value must change away from the its output limit
before limit status is turned off.
BKCAL_IN 27 EU of OUT_SCALE 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.
BKCAL_OUT 31 EU of PV_SCALE 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.