IOtech DaqBook/2000 Series, User Manual

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DaqBook/2000 Series and DaqOEM/2000 Series
898095
Device Overviews 2-5
Asynchronous I/O Operations
The DaqBook/2000 Series and DaqOEM/2000 Series devices allow asynchronous input of any counter or
digital channel that is not currently configured for synchronous acquisition. The devices also allow for
asynchronous output to any D/A channels not currently configured for waveform output. Likewise, the
16-bit P3 digital port, if available, 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
The DaqBook/2000 Series and DaqOEM/2000 Series devices have an implemented Intel 8255 core in the
digital I/O logic on the P2 port of the product. 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 an output port. With this port, no
configuration is required, the port simply outputs when written to and inputs when read.
The 16-bit P3
port does not apply to DaqBook/2020 .
Expansion Digital I/O
The DaqBook/2000 Series and DaqOEM/2000 Series devices have the ability to expand digital I/O through
the P2 port via digital I/O expansion modules. These modules are discussed in the
DBK Option Cards &
Modules User’s Manual . 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 additionally
Intel 8255 ports as well as input isolation for applications that require the expanded capabilities.
Pulse Stream Output Using Timers
The DaqBook/2000 Series and DaqOEM/2000 Series devices allow 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.
Analog Output Channels
The DaqBook/2001, DaqOEM/2001, and DaqBook/2020 have the ability to output analog data to any of
the available (up to 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. DaqBook/2005
and DaqOEM/2005 do not have analog output capability.
Counter Input Channels
The DaqBook/2000 Series and DaqOEM/2000 Series devices have counter input capabilities and have the
ability to read counter input [if the counter channel is not configured for synchronous acquisition]. As in
the case of synchronous operations the 4 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.