National Instruments NI 9751, Руководство пользователя, Страница: 5 / 30

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NI 9751 User Manual
Hardware
The NI 9751 provides three channels for driving unipolar solenoid and piezo injectors in a
National Instruments cRIO module. Use the included internal boost power supply to provide
short phases of boosted voltages for higher current operation.
Powering the Module
The NI 9751 requires power from each of the following sources:
• The CompactRIO backplane male high density 15-pin DSUB (HD15) connector, which
mates with the female HD15 connector on the module. This power source provides a
regulated 5 V and ground to various digital logic functions. The CompactRIO 5 V source
is active whenever the CompactRIO or R Series Expansion Chassis is properly powered.
You can power the NI 9757 only at the HD15 connector by plugging it into a CompactRIO
or R Series Expansion Chassis. Do not connect the HD15 connector to any other device.
• The external screw terminal connector block, the terminals of which are labeled BATT (0)
and GND (9). A typical power source is an automotive 12 VDC or 24 VDC battery system,
but the NI 9751 can accept power from a range of 7 VDC to 32 VDC.
Caution You must use a UL-listed power supply with the NI 9751.
With the internal boost power supply and injector outputs disabled, the NI 9751 requires up to
100 mA from the external supply. The following formula calculates the total power required to
operate the module and drive injectors:
Where : Ip (A) = Peak current
Ih (A) = Hold current
HVTarget (V) = High Voltage Target from internal boost supply
BattV (V) = Battery voltage supplied to BATT(0)
Tip (sec) = Time of peak current phase
DurAve (sec) = Average duration of all injection pulses within an engine cycle
RPMmax (RPM) = Maximum engine speed in RPM
Nchan = Number of channels used
Npulse = Number of injection pulses per engine cycle
This formula assumes a 4-stroke engine cycle. For 2-stroke engines, multiply the result by 2.
Power
HVT et arg IP
×
Tip
×
2 0.70 ×
-----------------------------------------------------
BattV Ih × DurAve Tip
–
( ) ×
+
 
 
RPMmax Nchan
×
Npulse
×
2 60 ×
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×
=