National Instruments NI 9751 User Manual

NI 9751 User Manual | © National Instruments | 9
Module Temperature Fault (ModuleTemperature)
Due to the C Series module housing design, there is limited ability for heat to escape. The
primary source of heat within the NI 9751 is the internal boost power supply. If the internal
module temperature rises above approximately 80 °C, the module temperature fault is set.
High Voltage Limit Fault (HighVoltageLimit)
If the charge on the internal power supply exceeds 190 V, the high voltage limit fault sets. This
fault can occur due to excessive injector solenoid back-boosting. Excessive solenoid
back-boosting can be caused by driving solenoids with very high inductance while not using
the boost supply.
Internal Boost Power Supply Benchmarks
Table 2 describes bench test results that demonstrate power supply capability.
With air flow over the NI 9751, you can extend the duration of operation at heavy loads.
Table 2. Bench Test Results
Test Condition
Test 1
(Solenoid)
Test 2
(Solenoid)
Test 3
(Piezo)
External Battery Voltage (V) 13.8 13.8 13.8
HVTarget (V) 75 75 190
PeakCurrent (A) 27 27 8
PeakTime (ms) 0.18 0.18 s N/A
HoldCurrent (A) 15 15 N/A
BackBoostTime (ms) 0.20 0.20 N/A
Number of injectors operated 3 3 2
Number of fuel pulses per cycle 1 5 1
Simulated engine speed (RPM) 5,000 2,000 7,200
Length of test (min) 10 10 480
Ambient temperature (°C) 25 25 25
Final module temperature (°C) 50 75 72
Temperature stabilized? Y N Y
Injector under test Bosch P/N 0445 110 072
Mercedes Benz P/N 611 070 09 87
Bosch P/N
0445 115 027

National Instruments NI 9751 Specifications

General

Brand	National Instruments
Model	NI 9751
Category	Control Unit
Language	English