Cla-Val X117C - Manual (Page 2)

After loosening the setscrew, move the spool by hand (up and
down) to check that the roller and spool are in alignment throughout
entire valve stroke. The actuating arm should not be moved more
than 30 degrees up or down from horizontal centerline of knurled
shaft. The centerline of the roller should not be past the lower lip
or rim of the spool at any valve position. You may have to adjust
the length of the actuating arm when doing this.
You will feel the spring restoring force of the transmitter as you do
this step. This restoring force allows the roller to maintain contact
with the lower lip of the spool throughout the entire valve stroke.
The spool must now be adjusted into place by moving the spool
slightly (approximately 1/4") upward to engage this spring force.
Tighten spool setscrew when the actuating arm is angled about 30
degrees downward.
6. Remove transmitter cover and temporarily connect calibration
wiring equipment (milliamp meter and power supply or portable
instrumentation calibrator/tester to transmitter screw terminals.).
Refer to calibration equipment and adjust potentiometer marked
“NULL” until the meter reads 4 mA. A clockwise turn increases
output. Use care in adjusting the potentiometer by not pressing in
on the adjusting stem while turning the screwdriver. This will affect
the reading.
ALTERNATE METHOD: Loosen setscrew on spool and adjust
until its centerline is lined up with centerline of transmitter actuating
arm pivot centerline (actuating stem and actuating arm should be
at 90 degrees to each other). Mark top and bottom of spool location
on stem at this ‘halfway’ position. Determine valve stroke by mul-
tiplying .281 times the valve seat diameter. Measure half the valve
stroke down from bottom of the spool and mark the stem. Move
the spool down until the bottom of the spool is aligned with the new
mark on the stem. Tighten the spool setscrew. Loosen the screw
that holds roller arm in place and move roller arm end into spool.
Adjust location of transmitter on bracket so that roller is in place
inside spool and slightly touching the bottom lip or rim of spool.
The transmitter spring restoring force helps locate the roller on the
lower lip of the spool throughout the entire valve stroke. The roller
arm should be at an angle of between 30 and 40 degrees below
the horizontal centerline of the pivot arm.
7. For the most accurate calibration it is necessary to open valve
fully. CAUTION: This will either allow a high flow rate through the
valve, or the downstream pressure will quickly increase to the inlet
pressure. In some cases, this can be very harmful. Where this is
the case, and there are no block valves in the system to protect
the downstream piping, it should be realized that steps should be
taken to remedy this situation before proceeding further. Normally,
block valves are to be used to protect downstream piping while the
valve is in the open position. Close downstream block valve. Vent
cover chamber to atmosphere. Slightly open inlet block valve.
Allow valve to open while fluid is vented from cover chamber.
When flow stops valve is in the fully open position. Note: continuous
leakage from cover chamber could mean additional troubleshooting
of the main valve or pilot system must be done.
8. With valve in fully open position, inspect position of spool and
roller arm. Actuating arm roller should be making good contact
with the lower lip or rim of the spool and the centerline of the roller
should not be past the lower lip or rim of the spool (see Step 5).
Adjust if necessary.
Refer to calibration equipment (see Step 6) and adjust potentiometer
marked “SPAN” until the meter reads 20 mA. A clockwise turn
increases output. Use care in adjusting the potentiometer by not
pressing in on the adjusting stem while turning the screwdriver.
This can affect the reading.
ALTERNATE METHOD: If it is not possible to cycle valve position
without damage, then with valve remaining in the “valve closed”
position loosen the spool piece setscrew and slide spool upward
to the original “halfway” marks on the stem. Adjust the “SPAN”
potentiometer until the meter reads 12 mA. Slide the spool piece
down until the meter reads 4 mA and tighten setscrew on spool.
This method is less accurate than fully cycling valve but will work.
9. There is some interplay between: 1.) The “span” and “null” settings,
2.) The 4 to 20 mA signal and, 3.) The actual valve open and
closed positions. Repeat steps above. Cycle valve from open to
closed positions and check settings as necessary to achieve
desired valve position signal accuracy.
10. Remove all calibration equipment and attach permanent
wiring. Recheck wiring and output signals at remote location. See
Wiring section. Reinstall housing on transmitter. Recheck and
tighten all fasteners. Bleed air from main valve cover through
small bleed screw and washer located on one wrench flat of
adapter.
ADJUSTING OPTIONAL LIMIT SWITCHES
These switches are supplied with X117CLS models and are factory
set to operate at valve closed position.
1. Lift cam follower arm.
2. Move cam wheel axially to disengage teeth on wheel from teeth
on shaft disc.
3. Turn cam wheel to desired position. Turning in direction of shaft
rotation advances operate point. Pretravel decreases and overtravel
thereby increases. Each notch on the cam wheel represents an
operating point change of 7 degrees 20 seconds arc. The symbols
on the cam wheel simplify changing rotation from clock wise to
counterclockwise to center neutral, or vice versa.
The switch operates on clockwise and counterclockwise rotation,
the pointer on the cam follower lines up with symbol [ l\ ] or symbol
[ /l ] on the cam wheel. Maximum pretravel of 15 degrees occurs
when symbol [ /l ] lines up. Maximum pretravel of 80 degrees
occurs when symbol [ l\ ] lines up. Operation is in the direction
of the inclined surface of the symbol when [ l\ ] or [ /l ] lines up
with the pointer on the cam follower.
4. When cam wheel has been rotated to desired location, release
cam wheel to engage with mating shaft disc.
5. Release cam follower arm.