6
4.2 Posit
The Logix 320
instrument. F
installed on a
action.
The Logix 320
mA input signa
communication
signal: Analog
signal is used f
level of the inp
sent via HART
command sou
the HART 375
Whether in An
as the valve cl
the valve open
signal is conve
the signals cor
The input sign
characterizatio
longer uses C
characterize th
done in softwa
adjustment. T
Equal Percent
Figure 1: Logi
tioner Oper
00MD positione
igure 1 shows
double-acting
0MD receives p
al. However, sin
ns, two sources
and Digital. In
for the comman
ut 4-20 mA sign
T, is used as the
rce can be acce
communicator,
nalog or Digital
losed position a
n position. In A
erted to a perce
rresponding to
nal in percent p
on/limits modifi
CAMs or other m
he output of the
are, which allow
The positioner h
t
(= %) and
Cu
ix 3200MD Dig
ation
er is an electric
a Logix 3200M
linear actuator
power from the t
nce this position
s can be used fo
Analog source,
nd source. In D
nal is ignored an
e command sou
essed with Valv
, or other host s
Source, 0 % is
and 100 % is al
Analog source, t
entage. During
0 % and 100 %
passes through
ier block. The
mechanical me
e positioner. T
ws for in-the-fie
has three basic
ustom
characte
ital Positioner S
Use
c feedback
MD positioner
for air-to-open
two-wire, 4-20
ner utilizes HAR
or the command
the 4-20 mA
igital source, th
nd a digital sign
rce. The
veSight software
software.
always defined
ways defined a
the 4-20 mA
loop calibration
% are defined.
a
positioner no
eans to
This function is
eld customer
c modes:
Linea
rization.
Schematic (air-
er instructions –
n
RT
d
e
nal,
e,
d
as
n,
ar
,
In
Linea
to the c
(= %) m
rangeab
enabled
output c
curve.
defined
addition
(Minimu
The act
any cha
called t
The Log
algorith
control
again to
measur
Comma
deviatio
inner-lo
upon th
spool p
stem be
deviatio
This pro
r-to-open config
– Digital Positio
ar
mode, the in
control algorithm
mode, the input
bility = % curve
d, the input sig
curve or a cust
The custom us
d using a handh
n, two user-def
um Position Cu
tual command
aracterization o
the
Control Com
gix 3200MD us
hm. The two st
and an outer-lo
o Figure 1, a st
rement of the s
and is compare
on exists, the c
oop control to m
he deviation. T
position. The a
egins to move.
on between
Co
ocess continue
guration)
oner 3200MD
nput signal is pa
m in a 1:1 trans
t signal is mapp
e. If
Custom
ch
nal is mapped
tom, user-defin
ser-defined 21-
held or ValveS
fined features,
utoff), may affe
being used to
or user limits ha
mmand.
ses a two-stage
tages consist o
oop, stem posi
tem position se
stem movemen
ed against the
control algorithm
move the spool
The inner-loop t
ctuator pressu
The stem mo
ontrol Comman
es until the dev
LGENIM0059-
flowse
assed straight
sfer. In Equal
ped to a standa
haracterization
to either a defa
ned 21-point ou
-point output cu
ight software.
Soft Limits
and
ect the final inpu
position the ste
ave been evalu
e, stem-positio
of an inner-loop
ition control. R
ensor provides
nt. The Contro
Stem Position.
m sends a sign
up or down, d
then quickly ad
res change an
ovement reduce
nd
and
Stem Po
viation goes to z
-04 09/11
erve.com
through
Percent
ard 30:1
n is
ault = %
utput
urve is
In
d
MPC
ut signal.
em, after
uated, is
oning
p, spool
Referring
a
l
If any
nal to the
epending
djusts the
d the
es the
osition
.
zero.
