Farm Fans C-2120A, Руководство оператора, Страница: 16 / 68

14
NOTE: As previously stated, with the Meter Roll
Selector set to Manual, the Moisture Controller can
only display grain temperature, but cannot control
meter roll speed. With Meter Roll Selector set to OFF,
the Moisture Controller display is also off.
SETTING TEMP
a. Push the DISP (display) button once and current set-
point will be displayed as indicated by the letters SP
(setpoint) in the lower left-hand corner.
b. Raise or lower Setpoint to desired temperature by
pushing the triangle buttons to increase or decrease.
c. Push RESET to return to measured temperature. SP
will not be displayed. If display is inactive for 60 sec-
onds, it will automatically return to measured tempera-
ture display. If moisture control is turned off while in the
SP mode, the newly entered setpoint will be canceled.
Operating with Automatic Moisture Control
1. See Drying Time Tables in Section 5 for initial drying
time, and Dryer Operation Charts also in Section 5 for
initial % Unload Rate. Then start the dryer on manual
control.
2. Measure discharged grain moisture. If adjustments are
required, change the Manual Control Dial as required;
allow dryer to operate for one grain pass before
rechecking moisture.
Note: Time (min.) = Holding Capacity (Bu.) x 60
for one grain pass
Unload Rate (Bu/Hr)
3. After the grain discharge has been readjusted and sta-
bilized at desired moisture content, note the tempera-
ture on the Moisture Controller and adjust the setpoint
to the temp noted. Be sure to push Reset button after
entering a new setpoint before proceeding.
4. Move the Unloading Switch from MAN to OFF, then to
AUTO, pausing 5 to 6 seconds in the OFF position.
This pause is necessary for the Moisture Control to
reinitialize. If the Moisture Control has been correctly
reinitialized, first zero degrees and then the correct
grain temperature will display after the switch is set to
AUTO. Failure to wait for a complete reset can cause
a lengthy delay in the time the Moisture Control needs
to arrive at the correct meter roll speed. Also important:
Do not change the manual unload rate dial while in the
auto mode.
5. The Moisture Controller will begin automatically con-
trolling the meter roll speed to compensate for changes
in the grain input moisture by maintaining the setpoint
temperature entered.
6. If large changes in grain input moisture are encoun-
tered, repeat the setup procedure to establish a new
setpoint temperature.
7. When restarting a loaded dryer following a shutdown
period, the dryer should be operated in the MANUAL
mode, until the newly dried grain has passed the RTD
grain sensor (2/3 of the grain pass time) and the grain
temperature has stabilized, before switching to the
AUTOMATIC mode. The Moisture Control setpoint
should not require readjustment.
METER ROLL MONITOR SYSTEM
Operation — The meter roll monitor system is designed
to provide automatic shutdown of the dryer if the meter
rolls fail to rotate due to obstructions, malfunction, or
forgetting to turn the meter roll selector switch ON. The
monitor system will function only when the unload
auger circuit is energized, as required for normal meter
roll operation.
The main monitor system components are briefly
described as follows:
Proximity — The Meter Roll Proximity switch is mount-
ed on the meter roll drive end of the dryer, on the side
opposite the SCR drive motor. This switch senses the
rotation of the meter rolls and sends an electrical signal
to the meter roll monitor in the ASC control box. (See
Fig. 3-4 and General Control Circuit in Section 8.) The
light on the switch indicates LOAD ON each time a
rotation has been sensed.
The proper switch adjustment is 1/4” clearance
between Proximity switch head and the rotating target.
The Proximity switch is slotted to allow readjustment, if
required. When properly adjusted, the LOAD ON indi-
cator will light every time the target rotates near the
proximity switch. (For service information, see Bulletin
MRM-02-2.)
NOTE: Earlier meter roll monitor switches used a set
screw and two hex nuts as a rotating target. The sug-
gested gap for this type switch is 3/4" between the
bearing collar and proximity switch sensing head.
Meter Roll Monitor — The meter roll rotation is moni-
tored by the solid state Meter Roll Monitor Relay in the
ASC control box. The monitor is active whenever the
Unload Auger switch is in the AUTO position. If the
Monitor fails to see a change (either opening or clos-
ing) in the Proximity Switch signal within three minutes,
the safety circuit will be broken and the dryer will auto-
matically shut down. The Monitor resets automatically
when the control start button is pushed.
PROXIMITY SWITCH
056-1865-7
1/4" GAP
SIDE
VIEW
ROTATING
TARGET
MRALT.DSF
Fig. 3-4 Meter roll monitor