STI DigitalTrak2 - 7 Fault and Maintenance; Trouble Shooting; Maintainance

INSTRUCTION MANUAL
DigitalTrak2™
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STI S.r.l. – Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 4054 – rev.00 02/2021 – DT2 - 24 -
7. FAULT AND MAINTENANCE
7.1 Trouble shooting
When positioner failed, follow these steps to eliminate fault,
If you cannot solve the fault according to steps as bellow, please contact STI.
Fault
Reason
Action to be taken
Actuator no action in
manual /auto state
Air pressure too low
Air pressure adjustment > 0.14MPa
Actuator jammed
Solve problem of actuator jammed
Actuator does not move
or moves slowly
Air pressure low
Regulate the air pressure to above
0.14MP
Exit initialization before finish
Re-initialize
Move frequently (not
oscillation)
Leakage in air loop
Check the air pipes
Oscillation
User configuration incorrect
Contact manufacturer if positioner
leak
Set larger dead band, larger setpoint
ramp
Volume of actuator is too
small
Set larger dead band, larger setpoint
ramp
Return difference is large
Adjust installation of bracket and
feedback position.
Re-initialize, if need.
Valve cannot be fully
opened or closed
Air pressure too low
Increase air pressure
Initialization data incorrect
Re-initialize
Position limit is set
Check user configuration
Tighten close not set
Active tighten close function
No display
Signal too small(<3.6mA)
Check input signal
Electrical connection terminal
screws loose
Tighten the terminal screws
Main board failed
Change the main board
Exhaust not smooth
Exhaust plug
Clean exhaust
No position feedback
current
Position feedback module
failed
Change the module
No external power, position
feedback module doesn’t work
Provide 24V power to the module
Polarity reversal of external
connection
Rewire
Feedback current
mismatch actual position
Position feedback module
failed
Change the module
Zero or Span drift
Tune the zero or span trimmer of
module
Position display on LCD
mismatch actual position
Actuator travel range
mismatch the scale
Manual initialize
7.2 Maintainance
1) Positioner is an instrument which should be regularly maintained. The air supply of positioner should be kept
dry and clean. Regularly exhaust water and pollution of the regulator connecting the positioner in order to keep
the positioner normally.
2) Feedback connection may be loose due to long term work. Check the feedback connection regularly. If loose,
tighten at once and decide whether to initialize or not according error of zero and span.
3) In order to see whether the positioner is normal, keep the pressure gauge clear.