Samson 373 Series - Drive Signal Diagram Steady-State (D1)

3.1 Drive signal diagram
steady-state (d1)
As described in detail in section 2.5 on the
drive signal diagram, the drive signal y plot
-
ted versus valve position x allows the follow
-
ing changes at the control valve to be recog
-
nized (and an alarm issued):
4
Air leakage in the pneumatics
4
Spring force reduced
4
Changes in the supply pressure
This test (
tESt d1 ) causes the valve to move
through the travel range to allow the results
and alarms issued in automatic mode to be
accurately checked.
After starting the test, the valve is moved to
various fixed valve positions x distributed
over the full range of the valve.
The drive signal y is measured for each
valve position x and stored in the positioner
memory. The necessary data set for the ref
-
erence graph is automatically plotted and
stored directly after initialization. The start
time for the reference graph is stored with a
reference time stamp in the positioner’s
non-volatile memory.
Any further measurement is stored as a re
-
peated measurement. Previously recorded
repeated measurements stored in the
positioner are overwritten. However, note
that you can upload previous repeated mea
-
surements to a PC before starting a new test.
While the test is active,
d1 and tESt appear
on the positioner display in alternating se-
quence and indicates manual operating
mode.
22 EB 8388 EN
Tests MAN
Fig. 11 · Drive signal diagram steady-state