Converting Raw Data Values to Voltage
You can use the following equations to convert raw data values to volts:
V = Raw Data Value × LSB Weight
LSB Weight = Nominal Range ÷ 2
ADC Resolution
where
Raw Data Value is the value returned by reading in the input channel,
LSB Weight is the value in volts of the increment between data values,
Nominal Range is the absolute value in volts of the full, peak-to-peak nominal range of
the channel,
and ADC Resolution is the resolution of the ADC in bits (ADC Resolution = 12)
•
For AI and AO channels on the MXP,
LSB Weight = 5
�
÷ 2
12
= 1.221
��
Maximum Reading = 4095 × 1.221
��
= 4.999
�
•
For the accelerometer,
LSB Weight = 16
�
÷ 2
12
= 3.906
��
Maximum Positive Reading = + 2047 × 3.906
��
= + 7.996
�
Maximum Negative Reading =
−
2048 × 3.906
��
=
−
8.000
�
Front Panel Buttons
Reset Button
Pressing and releasing the Reset button restarts the processor and the FPGA.
Pressing and holding the Reset button until the status LED lights (about five seconds) and then
releasing the Reset button restarts the processor and the FPGA and forces the NI roboRIO into
safe mode. In safe mode, the NI roboRIO launches only the services necessary for updating
configuration and installing software.
When the NI roboRIO is in safe mode, you can communicate with it by using the serial lines
on the RS-232 serial port. You must configure your serial-port terminal program with the
following settings:
•
115,200 bits per second
•
Eight data bits
•
No parity
NI roboRIO User Manual
|
© National Instruments
|
17
