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102 Programming the HP E1415 for PID Control
system being ready to receive trigger.
•
FIFO overflowed. In either FIFO mode, data was received after the
FIFO was full.
•
Overvoltage detection on input. If the input protection jumper has not
been cut, the input relays have all been opened, and a *RST is required
to reset the HP E1415.
•
Scan complete. The HP E1415 has finished a scan list.
•
SCP trigger. A trigger was received from an SCP.
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FIFO half full. The FIFO contains at least 32768 values.
•
Measurement complete. The trigger system exited the "Wait-For-
Arm". This clears the Measuring bit in the OPER register.
•
Algorithm executes an "interrupt()" statement.
These HP E1415 interrupts are not always enabled since, under some
circumstances, this could be detrimental to the users system operation. For
example, the Scan Complete, SCP triggers, FIFO half full, and
Measurement complete interrupts could come repetitively, at rates that
would cause the operating system to be swamped processing interrupts.
These conditions are dependent upon the user's overall system design,
therefore the driver allows the user to decide which, if any, interrupts will be
enabled.
The way the user controls which interrupts will be enabled is via the *OPC,
STATUS:OPER/QUES:ENABLE, and STAT:PRESET commands.
Each of the interrupting conditions listed above, has a corresponding bit in
the QUES or OPER registers. If that bit is enabled via the
STATus:OPER/QUES:ENABle command to be a part of the group
summary bit, it will also enable the HP E1415 interrupt for that condition. If
that bit is not enabled, the corresponding interrupt will be disabled.
Sending the STAT:PRESET will disable all the interrupts from the HP
E1415.
Sending the *OPC command will enable the measurement complete
interrupt. Once this interrupt is received and the OPC condition sent to the
status system, this interrupt will be disabled if it was not previously enabled
via the STATUS:OPER/QUES:ENABLE command.
The above description is always true for a downloaded driver. In the C-SCPI
driver, however, the interrupts will only be enabled if cscpi_overlap mode is
ON when the enable command is given. If cscpi_overlap is OFF, the user is
indicating they do not want interrupts to be enabled. Any subsequent
changes to cscpi_overlap will not change which interrupts are enabled. Only
sending *OPC or STAT:OPER/QUES:ENAB with cscpi_overlap ON will
enable interrupts.
In addition the user can enable or disable all interrupts via the SICL calls,
iintron() and iintroff().
Chapter 3
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