HP VXI 75000 C Series, User'S And Scpi Programming Manual

Page: 101 / 438

Programming the HP E1415 for PID Control 101 Chapter 3
Clearing Event Registers
To clear the Event Registers without reading them execute:
*CLS
clears all group’s Event
Registers
Reading Condition
Registers
The Questionable Data and Operation Status Groups each have a Condition
Register. The Condition Register reflects the group’s status condition in
"real-time". These registers are not latched so transient events may be
missed when the register is read. The commands to read these registers are:
STAT:QUES:COND?
Questionable Data Group
Condition Register
STAT:OPER:COND?
Operation Status Group
Condition Register
HP E1415 Background Operation
The HP E1415 inherently runs its algorithms and calibrations in the
background mode with no interaction required from the driver. All resources
needed to run the measurements are controlled by the on board Control
Processor (DSP).
The driver is required to setup the type of measurement to be run, modify
algorithm variables, and to unload data from the card after it appears in the
CVT or FIFO. Once the INIT[:IMM] command is given, the HP E1415 is
initiated and all functions of the trigger system and algorithm execution are
controlled by its on-board control processor. The driver returns to waiting
for user commands. No interrupts are required for the HP E1415 to complete
its measurement.
While the module is running algorithms, the driver can be queried for its
status, and data can be read from the FIFO and CVT. The ABORT command
may be given to force continuous execution to complete. Any changes to the
measurement setup will not be allowed until the TRIG:COUNT is reached,
or an ABORT command is given. Of course any commands or queries can
be given to other instruments while the HP E1415 is running algorithms.
Updating the Status System and VXIbus Interrupts
The driver needs to update the status system’s information whenever the
status of the HP E1415 changes. This update is always done when the status
system is accessed, or when CALibrate, INITiate, or ABORt commands are
executed. Most of the bits in the OPER and QUES registers represent
conditions which can change while the HP E1415 is measuring (initiated).
In many circumstances it is sufficient to have the status system bits updated
the next time the status system is accessed, or the INIT or ABORt commands
are given. When it is desired to have the status system bits updated closer in
time to when the condition changes on the HP E1415, the HP E1415
interrupts can be used.
The HP E1415 can send VXI interrupts upon the following conditions:
•
Trigger too Fast condition is detected. Trigger comes prior to trigger