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Remote Sensor Selection (J8)
The Multi-SD is compatible with Sensors P1-F through P9-F
shown on SmartFan Catalog Sensor page. Control
temperature is a function of the temperature sensor
selected and the position of the shunt (S3) on header J7.
Jumper Settings (J3, J6, J7)
There are three jumper settings that must be reviewed prior
to applying power to the Multi-SD: Output Voltage (J3),
Control Temperature (J7) and Number of Thermistors (J6).
Settings are based on the particular application. Following
is a description of each jumper setting.
Output Voltage Setting (J3): The Multi-SD can provide
power to 12 VDC, 24 VDC or 48 VDC fans from a 10-75
VDC input voltage source. Table 3 describes the function
of each setting. If the shunt is removed, the default fan
type is 12 VDC.
Number of Thermistor Sensors (J6): Use shunt S2 on
header J6 to indicate the number of thermistor sensors that
are connected to header J8. Table 4 describes the function
of each setting. When controlling based off of a PWM
input control signal shunt S2 should be in the 1 position on
header J6.
Control Temperature Setting (J7): The control
temperature is the temperature at which the maximum
voltage is applied to the fans. Header J7 allows selection
from three different control temperatures. Table 5 shows
the control temperature value for each jumper setting. If
the jumper is removed, the default setting is M.
Fan Speed Control
Temperature based fan control: The voltage applied to
the fan(s) is determined by the temperature sensor(s)
connected to header J8. Single point or multiple point
sensing can be accomplished by connecting one to three
thermistor sensors to positions T1, T2 and T3. The sensor
reading the hottest temperature is used for fan voltage
control when more than one sensor is used. The
relationship between fan voltage and sensed temperature is
shown in Figure 4.
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PWM based fan control: The voltage applied to the fans
can be controlled based on an isolated PWM signal applied
to position T3 on header J8. PWM switching frequency
should be in the range of 0.1 to 10 kHz. Figure 5 shows
the relationship between the control signal applied at
header J8:T3 and the fan voltage. NOTE: Fan voltage is
100% at a duty cycle of 0%. When a PWM signal is
applied to J8:T3, no connections should be made to T1 or
T2. When controlling based off of a PWM input control
signal shunt S2 should be in the 1 position on header J6.
Note: Alternative control curves can be provided on
special request. Contact Control Resources’ Sales
Department for details
High Temperature Alarm (J4)
A normally closed alarm output is provided at header J4 to
indicate when the sensed temperature is 10°C above the
control temperature. Table 6 shows the status of the alarm
output under various operating conditions and Table 7
shows the electrical rating of each output type.
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