Io Menu; Digital Io; Trigger Bus - VTI Instruments EX1000A User Manual

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The Blocking Mode control governs the system behavior if the reading buffer fills to its maximum
capacity during scanning. With blocking mode enabled, additional readings are discarded, leaving
the contents of the buffer intact. With blocking mode disabled, the buffer becomes circular, in that
additional readings overwrite the oldest readings.
IO M
ENU
The IO menu is used to receive and output data through the digital I/O port and trigger bus of the
EX10xxA.

Digital IO

This entry page is used to monitor the state of the 8-channel digital I/O port and control it as a
general purpose output device. Each DIO channel can be independently programmed with regards
to its output functionality, its static level to assume when enabled as an output, and pulse operation.
The Input State status section displays the measured digital level (0 or 1) of the DIO channels each
time the page is accessed or refreshed. The information does not update automatically on an input
level transition or on a timer. Consequently, it should only be used to monitor static or slowly
changing levels. The input monitoring functionality operates regardless of the state of the Output
Enable control.
The Output State control provides a pull-down selection in which the output level of each DIO
channel is specified. This setting represents the level that the channel will assume if/when enabled
as an output. When a channel is not enabled, this selection has no effect.
The Output Enable control enables each DIO channel as an output. Once enabled, a channel will
assume the level specified in the Output State control. When not enabled as an output, a channel
becomes tri-stated.
NOTE Before specifying a DIO channel as an output, ensure that no other active voltage drivers are
connected to the channel. Otherwise, incorrect operation or instrument damage could result.
The Pulse control is used to generate a single-shot 1 µs pulse. The specific operation of the pulse
depends on the static level programmed for that channel. When a channel is programmed with a
static level of high, the pulse will be low-going. When a channel is programmed with a static level
of low, the pulse will be high-going. Each pulse generation requires a separate command. This
control is only valid when the channel is enabled as an output. Normally, pulse operation is used
once a channel's static output level is already defined. However, if selections are applied together
to change the output state and output a pulse, the channel will first assume the new output state and
then output the appropriate pulse.
The Limit Event status section indicates (Y or N) the linkage of any DIO channels to a limit
evaluation condition. When linked, the output state of a channel will be primarily controlled by the
limit conditions specified in the DIO Limit Events page. The linkage is noted here, because
channels linked as DIO Limit Events are normally not used as direct control outputs. However,
direct output control is not disabled and can be used to asynchronously reset a linked channel.

Trigger Bus

This entry page is used to monitor the state of the 8-channel trigger bus (VTB) and control it as a
general purpose output device. Each VTB channel can be independently programmed with regards
to its output functionality, its static level to assume when enabled as an output, and pulse operation.
82 EX10xxA Web Page Operation