NI 9759 User Manual
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© National Instruments
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5
Analog Inputs
The NI 9759 provides two external analog inputs for accepting 0 V to 5 V signals. The primary
purpose of these inputs is for measuring potentiometer voltages. A regulated 5 V output and
ground terminal is provided for powering the potentiometer(s) of an electronic throttle body.
Caution
The 5 V output is not protected against short circuit to higher voltage
sources. Do not short this terminal to the H-Bridge driver terminals or BATT
terminal.
Other analog signals are also measured internal to the module and reported by the supplied VIs.
All measured analog signals are listed below:
•
Battery Voltage (V)
•
H-Bridge 1 Current (A)
•
H-Bridge 2 Current (A)
•
H-Bridge 1 Fault Line (reported with boolean, T=Fault, F=No Fault)
•
H-Bridge 2 Fault Line (reported with boolean, T=Fault, F=No Fault)
•
External Analog Input 1 (0 V to 5 V, Screw-Terminal 6)
•
External Analog Input 2 (0 V to 5 V, Screw-Terminal 7)
•
Internal Temperature
All eight analog inputs are sampled with a single multiplexed A/D converter at an aggregate rate
of 17.84 kHz. Each analog signal is sampled at 2.23 kHz. The A/D result can be used directly at
the FPGA level in ADC counts or at the RT level in converted engineering units.
The external analog inputs are protected from -6 V to +12 V inputs.
The external analog inputs are for connecting all wires of an electronic throttle directly to the
NI 9759. You can programmatically use the analog values for throttle control feedback. Other
analog inputs from another module may also be used to provide throttle position. Most electronic
throttle bodies have redundant position signals. When using only one electronic throttle, both
position signals may be connected to the NI 9759 and redundant throttle position is available.
When two electronic throttle bodies are used, only one position signal from each throttle may be
connected to the NI 9759, and redundant throttle position is not available. The additional
position signals may be connected to other analog inputs from other modules, making redundant
throttle position available for both throttles. A redundant position algorithm must be provided
by the user.
Figure 2 and 3 below show the typical connections for controlling single or dual throttles,
respectively. Table 1 below shows the terminal connections to a standard Bosch DV-E5
electronic throttle body.
