Test started automatically according to
schedule (ESD Auto)
ESD operating mode
parameter = “ESD
Auto“
Partial stroke tests are conducted at regular
intervals. The
Time until the next automatic
ESD test
parameter indicates when the next
test is scheduled (countdown).
Partial stroke test
The course of the partial stroke test depends
on the parameters listed under Settings in
TROVIS-VIEW 3. Depending on the param
-
eter settings, the partial stroke test is con-
ducted either in steps or in a ramp function
of the valve position (see Fig. 2).
After being triggered, the test does not start
until the
Settling time before test start
(t
1
) has
elapsed. This waiting period ensures that the
valve has reached the position defined by
the
Step start
parameter (pos. 2, see Fig. 2)
before the test starts.
Starting from the
Step start
position (pos. 2),
the valve moves to the defined end position
(
Step end
parameter, pos. 3). The valve re
-
mains in this position for the time defined by
the
Delay time after step
(t
2
) before perform
-
ing a second step change in the opposite di
-
rection from
Step end
(pos. 3) to
Step start
(pos. 2).
After the
Delay time after step
(t
2
) has
elapsed, the valve is moved back to its initial
position (=
Required manual reference vari
-
able w
, pos. 1)
The
Step tolerance limit
(range: 0.1 to
10.0 %) sets the permissible tolerance limit
for the step’s start and end values.
The
Scan rate
(range: 0.2 to 30.0 s) defines
the interval at which the measured values
are recorded during the test. The positioner
stores a maximum of 100 measured values
per measured variable (valve position x, ref-
erence variable w, setpoint deviation e,
drive signal y and the time when they were
recorded). After 100 measured values per
EB 8388-1 EN 9
ESD functions
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