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C-18
DriverLINX Configuration Notes
DriverLINX supports synchronous analog I/O using a shared pacing
clock source. To synchronize analog input with analog output, set up two
service requests as follows:
1. Analog Output Service Request (SR). The Timing Event should be a
Rate Generator using Logical Channel 0 (AI clock). This specifies
that the AO SR will use the same pacing source as the next, or
currently active, AI SR. The Period must be 0.
2. Analog Input SR with any valid Timing Event. When the AI task
starts sampling, the AO task will also sample using the same clock
source (internal or external).
Although both SRs share the same clock source, they are otherwise
logically independent of each other. Your application must manage and
respond to each Service Request separately. If the AI task terminates
before the AO task, the AO task will still be logically active, but the clock
will be send timing pulses to the AO task until the next AI task starts. If
you want to terminate the AO task when the AI task stops, either set up
both SRs with equal buffer sizes and Stop Events, or issue a Stop
operation request for the AO task.
External Clocking
Specify external clocking using a Rate Timing Event on channel 0 with an
external clock source specified. For hardware-independence, you can
specify the hardware external trigger channel by the symbolic constant,
DI_EXTCLK
. Connect the external clock source to
DI 0/XPCLK
[B39]
for DAS-1800HC or
XPCLK
[44] for other DAS-1800 models. The
hardware external clocking feature of the DAS-1800 supports positive or
negative active edge clocking. Note that the DAS-1800HC models use
DI 0/XPCLK
for both external clocking and digital input. BE SURE that
external clock source is TTL compatible, 0V minimum to +5V
maximum!
External Triggering
Specify external triggering using a Digital Start Event reading from the
digital input port (channel 0) or external trigger input (channel 2). For
hardware-independence, you can specify the hardware external trigger
channel by the symbolic constant,
DI_EXTTRG
. Digital Start Events
contain
mask
,
pattern
, and
match
fields. The mask is logically AND with
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