33
4.10 PID Control Block Parameter List
Parameter
Rel.
Index Description
Type Store Size
byte
RO /
R/W Min. Max. Default
ST_REV
1
The revision level of the static data associated with the func-
tion block. To support tracking changes in static para meter
attributes, the associated block’s static revision parameter
will be incremented each time a static parameter attribute
value is changed. Also, the associated block’s static revision
parameter may be incremented if a static para meter attribute
is written but the value is not changed.
Un-
signed
16
SRC
2
RO
0
TAG_DESC
2
The user description of the intended application of the block.
Octet
String
SRC
32
R/W
spaces
STRATEGY
3
The strategy field can be used to identify grouping of blocks.
This data is not checked or processed by the block.
Un-
signed
16
SRC
2
R/W
0
ALERT_KEY
4
Contains the identification number of the plant unit. It helps
to identify the location (plant unit) of an event.
Un-
signed
8
SRC
1
R/W
1
255
0
MODE_BLK
5
Contains the current mode and the permitted and normal
mode of the block.
DS-69
Mix
4
Mix
O/S
BLOCK_ERR
6
This parameter reflects the error status associated with the
hardware or software components associated with a block. It
is a bit string, so that multiple errors may be shown.
Bit
String
D
2
RO
PV
7
Either the primary analog value for use in executing the
function, or a process value associated with it. May also be
calculated from the READBACK value of an AO block.
DS-65
D
5
RO
SP
8
The analog setpoint of this block.
DS-65
N
5
R/W PV_SCALE
±10%
OUT
9
The primary analog value calculated as a result of executing
the function.
DS-65
N
5
R/W
OUT_SCALE
±10%
PV_SCALE
10
The high and low scale values, engineering units code, and
number of digits to the right of the decimal point to be used
in displaying the PV parameter and parameters which have
the same scaling as PV.
DS-68
SRC
11
R/W
0-100%
OUT_SCALE
11
The high and low scale values, engineering units code, and
number of digits to the right of the decimal point to be used
in displaying the OUT parameter and parameters which have
the same scaling as OUT.
DS-68
SRC
11
R/W
0-100%
GRANT_DENY
12
Options for controlling access of host computer and local
control panels to operating, tuning and alarm parameters of
the block.
DS-70
SRC
2
R/W
CONTROL_OPTS
13
Options which the user may select to alter the calculations
done in a control block.
Bit
String
SRC
2
R/W
0
STATUS_OPTS
14
Options which the user may select in the block processing of
status.
Bit
String
SRC
2
R/W
0
IN
15
The primary input value of the block, required for blocks that
filter the input to get the PV.
DS-65
N
5
R/W
PV_FTIME
16
Time constant of a single exponential filter for the PV, in
seconds.
Float
SRC
4
R/W
Positive
0
BYPASS
17
The normal control algorithm may be bypassed through this
parameter. When bypass is set, the setpoint value (in percent)
will be directly transferred to the output. To prevent a bump
on transfer to/from bypass, the setpoint will automatically be
initialized to the output value or process variable, respective-
ly, and the path broken flag will be set for one execution.
Un-
signed
8
SRC
1
R/W
1
2
0
CAS_IN
18
This parameter is the remote setpoint value, which must
come from another Fieldbus block, or a DCS block through a
defined link.
DS-65
N
5
R/W
SP_RATE_DN
19
Ramp rate at which downward setpoint changes are acted
on in Auto mode, in PV units per second. If the ramp rate is
set to zero, then the setpoint will be used immediately. For
control blocks, rate limiting will apply only in Auto. For output
blocks, rate limiting will apply in Auto, Cas, and RCas modes.
Float
SRC
4
R/W
Positive
+INF
SP_RATE_UP
20
Ramp rate at which upward setpoint changes are acted on in
Auto mode, in PV units per second. If the ramp rate is set to
zero, then the setpoint will be used immediately. For control
blocks, rate limiting will apply only in Auto. For output blocks,
rate limiting will apply in Auto, Cas, and RCas modes.
Float
SRC
4
R/W
Positive
+INF
SP_HI_LIM
21
The setpoint low limit is the lowest setpoint operator entry
that can be used for the block.
Float
SRC
4
R/W PV_SCALE
±10%
100
SP_LO_LIM
22
The setpoint high limit is the highest setpoint operator entry
that can be used for the block.
Float
SRC
4
R/W PV_SCALE
±10%
0
Parameter
Rel.
Index Description
Type Store Size
byte
RO /
R/W Min. Max. Default
GAIN
23
Dimensionless value used by the block algorithm in calculat-
ing the block output.
Float
SRC
4
R/W
0
