©
National Instruments Corporation
9
BNC-9920 Operating Instructions and Specifications
You can convert the count into total degrees rotated using the following formula:
Total Degrees Rotated
=
PULSES
×
3.75°/
pulse
where 3.75°/
pulse
= 360°/96
pulses
Calculate the number of revolutions and remaining degrees by dividing the total degrees rotated by 360
°
.
The calculated quotient is equal to the number of revolutions and the remainder is equal to the remaining
degrees.
Specifications
This section lists the specifications of the BNC-9920. These specifications are typical at 25 °C unless
otherwise specified.
Caution
Using the BNC-9920 defeats electrical isolation between C Series modules.
Note
Refer to the documents shipped with the C Series modules for specifications about analog and
digital I/O signals.
Analog Input
Number of channels (default) ................................8 differential
Field connections (default) ....................................8 BNC connectors
Protection ...............................................................No additional protection provided.
Refer to the C Series module specifications.
Optional inputs
AI 0 ................................................................Temperature sensor
AI 1 ................................................................Thermocouple
AI 3, AI 11 .....................................................Resistor measurement (requires RSE configuration)
Optional connections
Thermocouple ................................................Uncompensated miniature connector, mates with
2-prong miniature or subminiature connector
Resistor ..........................................................2 screw terminals
Resistor measurement range ..................................100
Ω
to 1 M
Ω
Resistor measurement error
...................................≤
5%
Screw terminals......................................................4 positions, 28–16 AWG wire
Switches
Floating source/grounded source ..................8
BNC/temperature reference IC .....................1
BNC/thermocouple connector.......................1
BNC/resistor screw terminals........................1
Analog Output
Field connection.....................................................2 BNC connectors
