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Synchronous Output Data Source (DaqScan/2001 and DaqScan/2004 only)
DaqScan/2001 and DaqScan/2004 allow the data source for synchronized DAC output
operations to be that of an internal memory-based buffer. The output data, for all channels, is
contained in the buffer.
Asynchronous I/O Operations
Each DaqScan/2000 Series device allows asynchronous input of any counter or digital channel
that is not currently configured for synchronous acquisition. The circuitry allows for
asynchronous output to any D/A channels that are not currently configured for waveform
output. Likewise, the digital port can be used for both asynchronous input and output
operations. In addition, the timer outputs can be programmed at any time regardless of the
current state of synchronous or asynchronous operations on other channels.
Digital I/O Channels
Local 8255 Channels (P2: Port A, Port B, Port C)
The devices have an implemented Intel 8255 core in the digital I/O logic on the P2 port. With
the Intel 8255 there are three 8-bit wide ports available for I/O and one 8-bit wide port for
configuration purposes. The configuration port is used to configure the other three 8-bit ports
for either input or output operations.
Local 16-bit P3 Port
The 16-bit P3 digital port can be used as either an input or output port. With this port, no
configuration is required. The port simply outputs when written to and inputs when read.
Expansion Digital I/O
The devices have the ability to expand their digital I/O capabilities via the P2 port and the
connection of applicable digital I/O expansion modules. These modules are discussed in the
DBK Option Cards & Modules User's Manual (p/n 457-0905). When using the digital I/O
expansion modules the local P2 Intel 8255 digital I/O becomes inaccessible in lieu of the
expansion modules. These expansion modules provide additional Intel 8255 ports as well as
input isolation for applications that require the expanded capabilities.
Pulse Stream Output Using Timers (Timer0, Timer1)
Each device allows for the generation of output pulses based upon a programmable setting.
These output timers can be set at any time regardless of the state of any synchronous or
asynchronous operations which are currently taking place on other channels.
The timer outputs are through screw terminals on the front panel.
Analog Output Channels (DaqScan/2001 and DaqScan/2004 only)
DaqScan/2001 and DaqScan/2004 can output analog data to any of their four D/A channels.
Each D/A channel may be asynchronously updated by an application if the D/A channel is not
currently being used for waveform output operations. The four analog outputs are via P3 (see
pinout in chapter 4).
Counter Input Channels (CTR0, CTR1, CTR2, CTR3)
DaqScan/2000 Series devices have counter input capabilities and have the ability to read
counter input providing that the counter channel is not configured for synchronous acquisition.
As in the case of synchronous operations the four 16-bit counter input channels can be used
individually or cascaded into two 32-bit counter channels. For either cascaded or non-
cascaded counter channels each channel can be configured for:
•
Clear on Read Mode - specifies that each counter should be cleared (reset to 0)
upon being read.
•
Continuous Totalize Mode – specifies that each counter is to free-run and not be
cleared during the read operation.
DaqScan/2000 Series
898195
Taking Measurements
8-5
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