Polling HP-IB Devices
Parallel poll is the fastest means of gathering device status when several
devices are connected to the bus. Each device (with this capability) can be
programmed to respond with one bit of status when parallel polled. This
makes it possible to obtain the status of several devices in one operation. If a
device responds affirmatively to a parallel poll, more information about its
specific status can be obtained by conducting a serial poll of the device.
Configuring Parallel Poll Responses
Certain devices, including the HP 16500C Logic Analysis System, can be
remotely programmed by a controller to respond to a parallel poll. A device
which is currently configured for a parallel poll responds to the poll by
placing its current status on one of the bus data lines. The response and the
data-bit number can then be programmed by the PPC (parallel poll
configure) statement. No multiple listeners can be specified in this
statement. If more than one device is to respond on a single bit, each device
must be configured with a separate PPC statement.
Example ASSIGN @Device TO 707
PPOLL CONFIGURE @Device;Mask
Status Reporting
Polling HP-IB Devices
7–11
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