VCIOM-05044
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DIgITal EPIC-2 TEChnICal Manual
InstallatIon and operatIng InstructIons
• PST I/O: the DEPIC-2 offers digital input to
activate the PST through an external dry
contact signal and provides the PST status
output on another digital output signal. This
setting can be enabled or disabled for this
functionality. Please read the DEPIC-2 IOM
for wiring and signal description.
FIguRE 46
accessing PST configuration menu
• auto PST: the DEPIC-2 offers a feature to
automatically perform a maintenance PST
on a regular time interval. The parameters in
this section allow the user to configure this
functionality in number of days.
• PST fail limits: this section has the
parameters that decides the pass/fail status
of the PST as explained below.
- Break pressure hysteresis: this parameter
is used to compare the maintenance PST
break pressure to the baseline PST break
pressure and if it is outside this hysteresis
limit, the DEPIC-2 considers the PST as a
failure. PST break pressure is the pressure
recorded when the DEPIC-2 observes
the initial valve movement from its fully
energized position during the PST.
- Travel-time hysteresis: this parameter is
used to compare the maintenance PST
travel-time to the baseline PST travel-time
and if it is outside this hysteresis limit, the
DEPIC-2 considers the PST as a failure. The
PST travel-time is the time recorded by the
DEPIC-2 when the valve start movement
from its fully energized position to the time
it reaches the travel-limit.
- Total-time limit: this parameter is OnlY
used in the case where the DEPIC-2 model
has the pressure sensors (Signature) option
disabled. In this case, this parameter is
used as a time limit for the PST. If the PST
doesn’t finish within this time, the DEPIC-2
considers the PST as a failure.
• PST travel-limit: this parameter (previously
known as PST Set-Point) defines the limit
DEPIC-2 cannot cross during the PST from its
fully energized position. For example, for 25%
travel limit on a fail closed valve, the PST will
fail if the valve travels more than 25% from its
energized position OR 75% actual position.
• PST travel-limit error: this parameter defines
the safe area during the valve movement.
For example, for 25% travel limit and 10%
travel-limit error setting, the DEPIC-2 will
make the valve move 15% and then energize
the solenoid to move the valve back to its fully
energized position to avoid surpassing the
25% hard travel limit.
• PST break-time hysteresis: this parameter
defines the hysteresis limit for the PST break
time parameter. During the maintenance
PST, the DEPIC-2 compares the break time
to the baseline PST’s break time and if it
is outside the hysteresis limit set in this
parameter, it generates an alert to warn the
user that the dynamics of the valve/actuator
package has changed.
• PST cycle limit: each time the DEPIC-2
perform a PST it keeps track of the number of
PST it has performed so far. The user can set
this parameter so that DEPIC-2 will generate
an alert to warn the user that the DEPIC-2
has performed certain number of PSTs on the
attached valve.
• PST cycle count: each time the DEPIC-2
perform a PST it keeps track of the number
of PST it has performed so far. This is a
parameter that provides this information
to the user. In addition, the user can reset
this parameter when the attached valve is
serviced or replaced with a new valve.
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