VXi VT1529A/B 사용자 설명서

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148 Programming the VT1422A for Data Acquisition and Control  
Reading Status
Groups Directly
It may be desirable to directly poll status groups for instrument status rather 
than poll the Status Byte for summary information. 
 Reading Event Registers
The Questionable Data, Operation Status and Standard Event Groups all 
have Event Registers. These Registers log the occurrence of even temporary 
status conditions. When read, these registers return the sum of the decimal 
values for the condition bits set, then are cleared to make them ready to log 
further events. The commands to read these Event Registers are:
STAT:QUES:EVENT?
Questionable Data Group Event 
Register
STAT:OPER:EVENT?
Operation Status Group Event 
Register
*ESR?
Standard Event Group Event 
Register
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
VT1422A Background Operation
The VT1422A 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 VT1422A is 
initiated and all functions of the trigger system, measurement scanning, 
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 VT1422A to complete its measurement.
While the module is scanning and/or 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 
VT1422A is running algorithms.