Determining The Fail-Safe Position - Samson 3731-5 Mounting And Operating Instructions

WARNING
!
Risk of personal injury due to moving parts on the valve. Injury to hands or fingers is possi-
ble if they are inserted into the valve.
− While the process is running, do not insert hands or fingers into the valve yoke and do not
touch any moving valve parts.
− Before exchanging the lever or changing the pin position, disconnect the supply air and
electrical power (bus line).

7.4 Determining the fail-safe position

Define the fail-safe position of the valve (0 % travel) taking the valve type and the actuator's
direction of action into account.
− AIR TO OPEN (AtO):
Signal pressure opens the valve, e.g. for a fail-close valve.
− AIR TO CLOSE (AtC):
Signal pressure closes the valve, e.g. for a fail-open valve
The AIR TO OPEN (AtO) setting always applies to double-acting actuators.
The fail-safe position setting remains unchanged on restart after a power supply failure.
1. Turn until Code 0 appears.
. MAN appears and Code 0
2. Press
blinks.
3. Turn until Init appears. Press
4. Turn until the required fail-safe position
appears.
5. Press to confirm.
6. Turn until ESC appears.
7. Press to exit the entry or to start
initialization as described in section 7.5.
EB 8387-5 EN
.
Operating the positioner
Initialization
AIR TO OPEN
AIR TO CLOSE
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