Keysight E6640A, Руководство пользователя и программиста по приложениям измерений

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3 Programming the Test Set
STATus Subsystem
2. It’s usually a good idea to start by clearing all the status registers with *CLS.
3. Sending the STAT:QUES:INT:ENAB 1024 command lets you monitor only bit 10 events, instead of the
default monitoring all the bits in the register. The register default is for positive transition events (0 to 1
transition). That is, when an auto-trigger timeout occurs. If instead, you wanted to know when the Auto-
trigger timeout condition is cleared, then you would set the STAT:QUES:INT:PTR 0 and the
STAT:QUES:INT:NTR 32767.
4. So now the only output from the Status Questionable Integrity register will come from a bit 10 positive
transition. That output goes to the Integrity Sum bit 9 of the Status Questionable register.
5. You can do a similar thing with this register to only look at bit 9 using, STAT:QUES:ENAB 512.
6. The Status Questionable register output goes to the “Status Questionable Summary” bit 3 of the Status
Byte Register. The output from this register can be enabled using the *SRE 8 command.
7. Finally, you would use the serial polling functionality available for the particular bus/software that you
are using to monitor the Status Byte Register. (You could also use *STB? to poll the Status Byte
Register.)
Using the Service Request (SRQ) Method
Your language, bus, and programming environment must be able to support SRQ interrupts. (For example,
BASIC used with VXI–11.3 (GPIB over LAN). When you monitor a condition with the SRQ method, you must:
1. Determine which bit monitors the condition.
2. Determine how that bit reports to the request service (RQS) bit of the status byte.
3. Send SCPI commands to enable the bit that monitors the condition and to enable the summary bits that
report the condition to the RQS bit.
4. Enable the controller to respond to service requests.
When the condition changes, the instrument sets its RQS bit. The controller is informed of the change as
soon as it occurs. As a result, the time the controller would otherwise have used to monitor the condition
can be used to perform other tasks. Your program determines how the controller responds to the SRQ.
Generating a Service Request
To use the SRQ method, you must understand how service requests are generated. Bit 6 of the status byte
register is the request service (RQS) bit. The *SRE command is used to configure the RQS bit to report
changes in instrument status. When such a change occurs, the RQS bit is set. It is cleared when the status
byte register is queried using *SRE? (with a serial poll.) It can be queried without erasing the contents with
*STB?.
When a register set causes a summary bit in the status byte to change from 0 to 1, the instrument can
initiate the service request (SRQ) process. However, the process is only initiated if both of the following
conditions are true:
•
The corresponding bit of the service request enable register is also set to 1.
•
The instrument does not have a service request pending. (A service request is considered to be pending
between the time the instrument’s SRQ process is initiated and the time the controller reads the status
byte register.)
W-CDMA & HSPA Measurement Applications Reference 143