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FAQs on the Counter/Timer features of KPCI-3108 or KPCI-3107
Below is a block diagram of the counter timer used on the KPCI-3108 or KPCI-
3107:
Architecture:
The 82C54 chip provides three 16bit counters: CT0, CT1 and CT2. DriverLINX
assigns the following logical channels to these counters:
Channel 0: 32bit cascade of CT1 and CT2
Channel 1: CT0
Channel 2: CT1
Channel 3: CT2
Connections:
For C/T functions that use inputs, such as event counting, simply connect to the
correct IPx pin number corresponding to the selected channel.
For C/T output functions, such as Square Wave Generation, the OPx must be
configured in the DriverLINX Configuration Panel to serve as CT outputs.
Access this from the `Special Button' on the Device tab for your assigned device
number (see below).
In each case, the IPx or OPx terminals are no longer available for their default
role as digital inputs or outputs if in use for C/T functions.
Crystal Timebase Values
The value of the timebase is software selectable:
INTERNAL1: corresponds to the setting in the DriverLINX Configuration Panel
(default is 5MHz)
INTERNAL2: 10 MHz
INTERNAL3: 5 MHz
INTERNAL4: 1 MHz
INTERNAL5: 100 KHz
Use Considerations
When performing paced Analog Input, logical channel 0 of the CT sub-system
will be used by default. This means that only CT0, logical channel 1, would still
be available for other tasks.
However, a CT channel other than the default 32bit cascaded channel could be
selected for the pacing source for the Analog Input task to increase the number
of counters available for other tasks. The only consequence to the Analog Input
task would be a reduction in the range of pacing frequencies available with a
single 16bit counter relative to 32bit cascaded channel.
See the Counter/Timer Channel Usage section of the `Using DriverLINX with
your KPCI-3108 Series Hardware' manual for more information.