Samson 3730-3 Operating Instructions Manual page 86

Tests
the 'Delay time after step' before performing
a second step change in the opposite direc-
tion from the fail-safe position to the start
position of the first step.
After the 'Delay time after step' has elapsed,
the valve moves back to its operating point.
The 'Tolerance limit of step response' param-
eter defines the permitted valve positions for
the start value and the end value for the step.
The 'Scan rate' defines the time interval be-
tween which the measured values are re-
corded during the test.
Test cancellation conditions
Various cancellation conditions provide ad-
ditional protection against the valve slam-
ming shut or moving past the end position.
The positioner cancels the full stroke test
Operating point + Tolerance limit
Operating point – Tolerance limit
Fig. 15: Course of the full stroke test with step response (left) and ramp function (right)
86
x [%]
100
Op. point
Settling time
before test start
Delay time
after step
when one of the following cancellation con-
ditions is fulfilled:
− 'Max. test duration': The test is canceled
when the maximum permissible test du-
ration is reached.
− 'Max. breakaway time' (Types 3730-4/-
5 only): The test is canceled when the
valve has not yet moved away from the
open position after the entered time has
elapsed.
This cancellation condition only becomes
effective after it has been activated ("Ac-
tivation 'Max. breakaway time'" = Yes).
− 'Allowed time to reach full closed posi-
tion' (Types 3730-4/-5 only): The test is
canceled when the valve has not yet
reached the closed position after the en-
tered time has elapsed.
Settling time
before test start
Delay time
after step
Delay time Delay time
after step after step
Ramp time Ramp time
falling rising
EB 8389 EN
t [s]