Serial Poll
The HP
supports the IEEE 488.1 serial poll feature. When
a serial poll of the instrument is requested, the RQS bit is returned on bit
6 of the status byte.
Using Serial Poll
This example will show how to use the service request by conducting a
(HP-IB)
serial poll of all instruments on the HP-IB bus. In this example, assume
that there are two instruments on the bus; a Logic Analyzer at address 7
and a printer at address 1.
The program command for serial poll using HP BASIC 4.0 is Stat =
The address 707 is the address of the oscilloscope in the
this example. The command for checking the printer is Stat =
because the address of that instrument is 01 on bus address
7. This command reads the contents of the HP-IB Status Register into the
variable called Stat. At that time bit 6 of the variable Stat can be tested to
see if it is set (bit 6 = 1).
The serial poll operation can be conducted in the following
1. Enable interrupts on the bus. This allows the controller to “see” the
SRQ line.
2. Disable interrupts on the bus.
If the SRQ line is high (some instrument is requesting service) then
check the instrument at address 1 to see if bit 6 of its status register
is high.
Status Reporting
HP
16518
B-6
Programming Reference