National Instruments 6368, Руководство пользователя

Страница: 174 / 278

© National Instruments
|
7-39
X Series User Manual
In addition, a counter’s Internal Output, Gate or Source can be routed to a different counter’s
Aux. A counter’s own gate can also be routed to its Aux input.
Some of these options may not be available in some driver software.
Counter n A, Counter n B, and Counter n Z Signals
Counter n B can control the direction of counting in edge counting applications. Use the A, B,
and Z inputs to each counter when measuring quadrature encoders or measuring two pulse
encoders.
Routing Signals to A, B, and Z Counter Inputs
Each counter has independent input selectors for each of the A, B, and Z inputs. Any of the
following signals can be routed to each input:
• RTSI <0..7>
• PFI <0..15>
• PXI_STAR
• PXIe_DSTAR<A,B>
• Analog Comparison Event
Routing Counter n Z Signal to an Output Terminal
You can route Counter n Z out to any RTSI <0..7> terminal.
Counter n Up_Down Signal
Counter n Up_Down is another name for the Counter n B signal.
Counter n HW Arm Signal
The Counter n HW Arm signal enables a counter to begin an input or output function.
To begin any counter input or output function, you must first enable, or arm, the counter. In some
applications, such as a buffered edge count, the counter begins counting when it is armed. In
other applications, such as single pulse-width measurement, the counter begins waiting for the
Gate signal when it is armed. Counter output operations can use the arm signal in addition to a
start trigger.
Software can arm a counter or configure counters to be armed on a hardware signal. Software
calls this hardware signal the Arm Start Trigger. Internally, software routes the Arm Start Trigger
to the Counter
n HW Arm input of the counter.