Flowserve 90 Series Controller - Manual (Page 2)

2 Positioner/Controller for Series 90 Modular Accessory System WCAIM2045
d. The M.A.S. circuit board can be set up in several ways for normal
operation, however, the board is designed to control over a 90°
swing only (a 180° swing with the appropriate actuator and pinion
gear). The adjustment trimpots on the board were not set up to
reduce actuator travel for a 4-20 mA input span. For example,
trying to adjust the board such that 4 mA is closed and 20 mA is
only 60% open is just not possible with the standard setup.
The standard setups are:
1) 4 mA for full clockwise rotation – i.e., 0° or 180° and 20 mA
for full counterclockwise rotation – i.e., 90°.
2) Split range where 4 mA would be full clockwise and 12 mA
would be full counterclockwise or 12 mA would be full
clockwise and 20 mA would be full counterclockwise.
3) Each of the above standard setups can also be made
reverse-acting.
e. Quite often when we receive an M.A.S. unit for repair at
Flowserve we find that the only thing wrong with the unit is that
the feedback potentiometer is out of calibration. It is very
important that the feedback potentiometer be properly calibrated
for correct operation of the positioner board. It is also very
important that the M.A.S. shaft not be rotated out of the quadrant
for which the feedback potentiometer has been calibrated.
Whenever you have a problem with positioner calibration, always
check the feedback potentiometer calibration first. This must be
done with the M.A.S. unit mounted to the 39 series actuator and
no power applied to the circuit board. If the actuator is in the full
clockwise position, check the resistance between the purple and
white/black potentiometer leads. The reading should be 80–90
ohms. If it is not, rotate the face gear until the proper reading is
achieved. If the actuator happens to be in the full counterclockwise
position, then check the resistance between the green and
white/black potentiometer leads. If necessary, adjust the face
gear for an 80–90 ohm reading.
Note: It is not necessary to loosen or remove face gear snap ring
to rotate gear; it is a friction fit.
2. ENVIRONMENTAL CONSIDERATIONS
a. General
CAUTION: The Worcester/McCANNA M.A.S. positioner/
controller circuit board is relatively insensitive to electrical
noise on signal and/or supply lines, and from noise in the
environment. Follow installation, calibration, and adjustment
guidelines carefully and use shielded wire as stated in
paragraph 2.d.
Flowserve recommends that all products which must be stored
prior to installation be stored indoors, in an environment suitable
for human occupancy. Do not store in areas where exposure to
relative humidity levels above 85%, acid or alkali fumes, radiation
above normal background, ultraviolet light, or temperatures above
120 degrees F or below 40 degrees F may occur. Do not store
within 50 feet of any source of ozone.
Temperature and humidity are the two most important factors that
determine the usefulness and life of electronic equipment.
b. Temperature
Operating solid state electronic equipment near or beyond its
high-temperature rating is the primary cause for most failures. It
is therefore very important that the user be aware of, and take
into consideration, factors that affect the temperature at which the
electronic circuits will operate.
Operating an electronic device at or below its low-temperature
rating generally results in a unit operating poorly or not at all, but
it will usually resume normal operation as soon as rated operating
temperatures are reached. Low-temperature problems can be
easily cured by addition of a thermostatically controlled heater to
the unit’s housing.
At high temperatures some components will destruct completely
when their maximum temperature is exceeded; others will cease
operation at temperatures above ratings and will return to
operation at normal ratings, but may have been permanently
changed in one or another parameter, causing a device to operate
poorly, and may also cause greatly reduced component life.
The Worcester/McCANNA M.A.S. positioner/controller circuit
board is rated for operation between 0 degrees F and 160 degrees
F. When using board, do not exceed the maximum ambient
temperature limit of 110 degrees F. in order to ensure that the
solenoid valves do not exceed a maximum temperature of 122
degrees F within the sealed M.A.S. package.
c. Humidity
Most electronic equipment has a reasonable degree of inherent
humidity protection and additional protection is supplied by
Flowserve in the form of a moisture proofing and fungicidal
coating.
Such protection will generally suffice for environments where the
average relative humidity is in the area of 80% or less and
ambient temperatures are in the order of 70 degrees F average
with only occasional short term exposure to temperatures up to
90 degrees F. Where relative humidity is consistently 80 to 90%
and the ambient temperature is high or subject to large variations
consideration should be given to installing a heater and
thermostat option in the enclosure. The heater should not
increase the enclosure temperature to the point where the
solenoid temperature rating of 122 degrees F is exceeded.
In those instances where the internal heater or high ambient
temperature would bring the solenoid’s operating temperature near
or above its maximum rating, the user should consider purging the
enclosure with a cool, dry gas. The initial costs can usually be paid
off quickly in the form of greatly extended equipment life, low
maintenance needs, and much less process downtime.
d. Shielding – Grounding of Shielding
Shielded wiring should be used for all signal input circuit wiring.
With a remotely mounted setpoint potentiometer for the controller
configuration of the M.A.S. Board, shielded wiring should be used
to connect the setpoint potentiometer to the M.A.S. board, for this
is also considered as signal input wiring.
Flow Control Division
Worcester Controls