Flowserve DFP17 - Manual (Page 17)

WCAIM2037 DataFlo Digital Electronic Positioner DFP17 Installation, Operation and Maintenance Instructions 17
4.3.14 Electronic Positioner Rotation Limits
(Electronic Travel Stops)
The display will alternately display yA and its position
value.
yA is the electronic lower rotation limit for shaft position
at the start of the signal range. It can be set to a value
from 0.0 to 100.0 in increments of 0.1 percent.
Press the UP switch to advance to the yE parameter
screen.
The display will alternately display yE and its position
value.
yE is the electronic upper rotation limit for shaft position
at the end of the signal range. It can be set to a value
from 0.0 to 100.0 in increments of 0.1 percent.
If yA were set at 20.0 then the actuator shaft would never
rotate further CW than 20 percent open. If yE is set to 70
percent then the actuator shaft would never rotate further
CCW than 70 percent open. These electronic limits
restrict the range of actuator shaft rotation.
yA must always be less than or equal to yE. yE must
always be greater than or equal to yA.
4.3.15 Tight Valve Shutoff
The display will alternately display yCLS and its setting.
yCLS is how we specify whether tight valve shutoff is
desired when the input signal reaches the low end of its
range. It is significant when the yA function is set to a
value other than 0.0 percent. The two choices are yES
and no. As an example, if the actuator/valve is controlling
fuel flow to a burner, yA might be set to 30 percent as a
low fire position, but between 4.1 and 4.2 mA the valve
would fully close if yCLS is set to yES to allow
maintenance to be performed on the burner.
4.3.16 Full Open Operation of Valve
with Open Travel Limit Set
The display will alternately display yOPn and its setting.
yOPn is how we specify whether the valve will fully open
when the input signal reaches the upper end of its range.
It is significant when the yE function is set to a value
other than 100.0 percent. The two choices are yES and
no. As an example, if yE is set at 70 percent and yOPn is
set to yES, then the actuator/valve would be 70 percent
open at 19.8 mA. but would open fully when the signal is
increased to 19.9 mA.
4.3.17 Brake on Time
The display will alternately display br and the brake time.
Actuator brake times from 0.10 to 0.99 seconds can be
selected in 0.01 second increments. The actuator brake
time begins after either the CW or CCW signal to the
actuator drive motors turns off.
Any control signal change will be ignored during the
brake ON period. The factory setting is .25 seconds, and
it is not recommended that this be changed. Ideally, the
brake ON time should be as short as possible to
minimize motor heating while at the same time
minimizing any overshoot caused by motor rotor inertia.
4.3.18 Restore Factory Default Values
The display will alternately display PrSt and no.
If yES is selected instead of no then the factory default
values for all parameters will be selected. This flag is not
a parameter but must be edited the same way to select
yES. This is a momentary function and values can be
altered after the default values have been selected. After
the factory default values have been reloaded, the display
will once again display no.
See Section 4.7 for a list of the default values.
4.3.19 Run Time Cycles for Maintenance
The display will alternately display CyS and the total
number of seconds for the valve to travel from full CCW
to full CW then back to full CCW. This cycle time is
measured in the cycle time calibration routine which is
performed after the feedback potentiometer calibration
routine.
The microprocessor converts run time into cycles.
The next screen displays accumulated cycles CyCn. The
number shown represents thousands of cycles. The
display can show up to 9.999 million cycles. Obviously at
higher cycles, less resolution is available on the display.
Only whole cycles are displayed.
With CyCn displayed, the user can press the SEL switch
and the total will begin flashing. At that point, holding
down the DOWN switch for four seconds will clear the
total.
Because the life of EEPROM is based on the number of
write operations, only every 100 cycles will cause the
total to be written to the nonvolatile memory.
4.3.20 Alarm Functions
The DEVIATION alarm becomes active if the valve does
not move to the desired position within a certain time
period. The time period is ten seconds plus either the
ramp time for the direction in which the actuator is
moving, or the open/close time from calibration,
whichever is greater.
A means to set UPPER and LOWER rotation alarm limits
on the actuator/valve shaft position is provided. An alarm
shall occur if the positioner rotates beyond either the
upper or lower set limit. The range of rotation limits is
from 0 to 100%. An example of typical alarm limits
would be 20% for LOWER and 80% for UPPER.
An opto-isolated open collector alarm output will be on
whenever any alarm condition exists.
Flow Control
Worcester Actuation Systems