Emergency Action - Samson 3730 Series Mounting And Operating Instructions

9.2 Emergency action

Fail-safe action is triggered by the i/p con-
verter or solenoid valve and upon supply air
failure. The positioner fully discharges its
pneumatic output to the atmosphere, causing
the pneumatic actuator to be vented. As a
result, the valve moves to the fail-safe posi-
tion. The fail-safe position depends on how
the springs are arranged in the pneumatic
actuator (air-to-close or air-to-open).
When the supply air fails, the optional sole-
noid valve or forced venting is triggered and
after reaching the shutdown signal, all posi-
tioner functions, except open/closed loop
control, remain active (including diagnostics
as well as position and status feedback).
Table 9-2: Further troubleshooting
Error description
No reading on the display
Actuator moves too slowly
Actuator moves in the wrong direction.
Air leaks from the positioner.
EB 8384-4 EN
Tip
Emergency action in the event of valve or ac-
tuator failure is described in the associated
valve and actuator documentation.
Î Plant operators are responsible for emer-
gency action to be taken in the plant.
Measures
Î Check electrical connection and electrical power.
Î Check the ambient temperature (the display's operat-
ing range is from –30 to +65 °C).
Î Check the supply pressure.
Î Deactivate software restriction.
Î Check the cross-section of the piping and screw fit-
tings.
Î Check the configuration of the mounting parts.
Î Check the characteristic setting.
Î Check the piping.
Î Check the configuration of the mounting parts.
Î Check attachment.
Î Check the seals in the connecting plate.
Malfunctions
9-3