Samson 3374 Series User Manual

EB 8331-4 EN 16-15
Annex A (conguration instructions)
16.13 Applications
Application: Positioner (POSI)
The actuator stem's position directly follows
the input signal.
Application: PID controller (PID)
The set point adjustable at the actuator is
used to position the valve using a PID algo-
rithm. The input signal at IN1, IN2 or IN3 is
used as the process variable. The PID con-
troller is adjusted using the parameters: Pro-
portional-actioncoefcientK
P
, Reset time T
N
,
Derivative-action time T
V
and Operating
point Y
0
:
Theproportional-actioncoefcientK
P
acts as
gain.
The reset time T
N
is the time it takes for the
integral component during a step response
in a PI controller to produce a change in the
manipulated variable identical to the change
produced by the P component. Increasing
the reset time T
N
reduces the rate of change
in the output when the set point deviation is
constant.
The derivative-action time T
V
is the time it
takes the rise response of a PD controller to
reach a certain manipulated variable value
earlier than it would take the response with
the P component only. Increasing the deriva-
tive-action time T
V
causes an increase in the
manipulated variable amplitude when the
rate of change is constant. After ramped
changes of the set point deviation, a longer
derivative-action time T
V
causes the D com-
ponent to have a longer effect.
The operating point Y
0
determines the posi-
tioning value, which is fed to the controlled
system when the process variable is the same
as the set point. The operating point is nor-
mally only important for P and PD control-
lers, but it can also be set for control strate-
gies PI, PID and I due to the possible limita-
tion of the integral-action component. For
control strategies with integral-action compo-
nent, the operating point can also be used
as the initial value for a restart.
When the PID application is used for tem-
peraturecontrolwithaPt1000sensor,the
temperature sensor is connected at the IN3
input(seethe'Installation'section).Pt1000
sensors can also be connected to the IN1
and IN2 inputs. Their measured values can
be read out over the RS-485 interface as
Modbusdatapoints(seesection16.16).
Application: Two-step mode (2STP)
The binary input IN2 is used for this func-
tion. When the binary input is in the active
switching state, the actuator stem retracts
(100%oftheadjustedtravelrange).When
the binary input is in the inactive switching
state, the actuator stem moves to the closed
position(0%).
Application: Three-step mode (3STP)
The binary input IN2 is used for this func-
tion to retract the actuator stem and binary
input IN3 to extend the actuator stem.
Application: Temperature closed-loop con-
trol upon input signal failure (POSF)
The travel follows the input signal. Upon fail-
ure of the input signal, the set point deter-
mined in the actuator by the integrated PID
controller is used to position the stem.

Samson 3374 Series Specifications

General

Velocity Sensitivity	Yes
Aftertouch	No
Pitch Bend	Yes
Modulation Wheel	Yes
Control Knobs	8
Transport Controls	Yes
USB	Yes
MIDI Out	Yes
Type	MIDI Controller
Power Source	USB