10
|
ni.com
|
NI 9751 User Manual
The internal power supply requires approximately 10 ms to charge from 12 V to 100 V, and
approximately 20 ms to charge from 12 V to 150 V. This charge-up process occurs immediately
when enabling the power supply. With the power supply enabled, the requested working voltage
is maintained while injection events are not commanded. Depending on the working voltage,
you might hear a slow frequency of faint clicks from the module. This is normal noise from the
power supply.
The DI Calibrator application can assist you in determining the proper current and voltage
profile settings to meet your injector solenoid requirements. NI will assist you with determining
calibration parameters for your injectors at no cost if NI can reuse the calibration data for future
projects. This does not include fuel flow measurements. You must provide NI with current
profile information and a test solenoid or injector.
When the internal supply is disabled, the high voltage bleeds down to battery voltage from 190 V
in approximately 3 minutes.
Connecting an External Power Supply to EXT PWR (7)
Connect an optional high voltage external power supply to the EXT PWR (7) terminal if the
internal boost power supply is overheating or cannot keep up with the injection requirements.
Inside the module, the external high voltage supply connects to the same internal capacitance as
the internal boost supply. Ensure that you make a permanent connection before you power the
external power supply. When an external high voltage supply greater than 24 V is detected, the
internal boost supply automatically shuts down. The BATT (0) terminal must still be connected
and powered by 7 V to 32 V even when you use an external high voltage supply connected to
the EXT PWR (7) terminal. A high voltage external power supply is not necessary for most
applications.
If the internal boost power supply cannot meet the demands of the application, consider using
only two of the three available channels instead of all three before using an external high voltage
power supply. For example, consider using three DI driver modules for a six-cylinder engine to
lighten the load on each module.
Suggested External High Voltage Supplies
TDK Lambda Genesys 100-15
Direct Injector Drivers
Injector Driver Circuit Description
The NI 9751 contains three solenoid DI drivers and can drive two Piezo injectors. The driver
channels share some circuitry, so injection events cannot overlap among channels within the
same module. If injection events with different injectors must overlap, you must use multiple
modules. The NI 9751 contain a high-voltage circuit and battery-voltage circuit that drive
current to the injector load. Figure 1 shows the high-voltage and battery-voltage drive circuits in
the simplified schematics for operating various types of injectors.
Summary of Contents for NI 9751
Page 1: ...SHC68 68 RDIO...