Fisher FIELDVUEDVC6200f Instruction Manual page 75

Instruction Manual
D103412X012
Figure 4‐7. Time Series Representation of Minimum PST Pause Time
NORMAL
OUTGOING
RAMP RATE
j
SETPOINT
OVERDRIVE
MINIMUM PST PAUSE TIME
j
MINIMUM TRAVEL MOVEMENT
k
MAX. ALLOWABLE TRAVEL
VST Outgoing Pressure Threshold defines the actuator pressure at which a partial stroke test will abort during the
outgoing stroke (see figure 4‐6). This prevents the DVC6200f from exhausting (or building) excessive pressure from/to
the actuator in an attempt to move a stuck valve. During PST Calibration, the Partial Stroke Outgoing Pressure
Threshold will be set automatically as follows:
Single Acting Actuators - For those actuators that exhaust pressure from the partial test start point, the Outgoing
Pressure Threshold will be a minimum value. For those actuators that build pressure from the partial test start point,
the Outgoing Pressure Threshold will be a maximum value.
Double Acting Actuators - The Outgoing Pressure Threshold will be set to a negative value for actuators where the
partial stroke start point is opposite of the Zero Power Condition (e.g., Partial Stroke Start Point = Open and Zero
Power Condition = Closed) and to a positive valve for actuators where the partial stroke start point is the same as the
Zero Power Condition.
The pressure signal used to determine this parameter depends on relay type and is summarized below.
Relay Type
A - Double-acting actuator
A - Single-acting actuator
B
C
B Special App.
C Special App.
To manually set the partial stroke Outgoing Pressure Threshold, you must examine current partial stroke test results
using ValveLink software. The following steps will guide you through the process:
INCOMING
RAMP RATE
RETURN
LEAD
TIME
PAUSE TIME
DISABLED
Pressure Signal
Port A - Port B
Port B
Port A
Port B
Port A
NORMAL
j
SETPOINT
OVERDRIVE
k
BREAKOUT
TIMEOUT TURNAROUND
MINIMUM PST PAUSE TIME
DVC6200f Digital Valve Controller
Detailed Setup - Transducer Block
REDUCED
PST TIME
RETURN
LEAD
EARLY
ENABLED
February 2017
TIME
75