Flowserve 3400IQ Digital Positioner - Manual (Page 25)

Logix 3400IQ Digital Positioner FCD LGENIM3401-00 – 06/06
flowserve.com
Auto Tune
This switch controls whether the positioner will auto tune itself every time the RE-CAL button is
pressed or use preset tuning parameters.
On On enables an auto tune feature that will automatically determine the positioner gain settings
based on the current position of the adjustable GAIN switch setting and response parameters
measured during the last RE-CAL. The GAIN switch is live, meaning the settings can be adjusted at
any time by changing the rotary switch position. (Note that there is a small black arrow indicating the
selection. The slot in the switch is NOT the indicator.)
Figure 10: Adjustable GAIN Switch
A
GAIN
B
C
D
E
F
G
H
If the adjustable GAIN selector switch is set to “E” with the auto tune switch on, a Flowserve standard
response tuning set will be calculated and used based on response parameters measured during the
last RE-CAL.
If the adjustable GAIN selector switch is set to “D”, “C”, “B”, or “A” with the auto tune switch on,
progressively lower gain settings will be used based on response parameters measured during the
last RE-CAL.
If the adjustable GAIN selector switch is set to “F”, “G”, or “H” with the auto tune switch on, progres-
sively higher gain settings will be calculated and used based on response parameters measured
during the last RE-CAL.
Off Off forces the positioner to use one of the factory preset tuning sets determined by the
adjustable GAIN selector switch. Settings “A” through “H” are progressively higher gain predefined
tuning sets. The GAIN selector switch is live and can be adjusted at any time to modify the tuning
parameters.
NOTE: “E” is the default adjustable GAIN selector switch setting for all actuator sizes. Raising or
lowering the gain setting is a function of the positioner/valve response to the control signal, and
is not actuator size dependent.
Stability Switch
This switch adjusts the position control algorithm of the positioner for use with low-friction control
valves or high-friction automated valves.
Low-Friction Valves Placing the switch to the left optimizes the response for low-friction, high-
performance control valves. This setting provides for optimum response times when used with most
low-friction control valves.