Fluke 9640A Series, Инструкция по эксплуатации

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SCPI and IEEE Bus Descriptions
Status Reporting System
4B
4B-17
Device-specific Error
This error shows that the instrument could not properly complete some device specific
operations.
Query Error
This error will occur when the Message Exchange Protocol is violated, for example,
when you send a query to the instrument and then send a new command without first
reading the response data from the previous query. Also, trying to read data from the
instrument without first sending a query to the instrument will cause this error.
Status Reporting Model
The Status Structure
The status reporting model used is standardized in IEEE 488.2 and SCPI, so you will find
similar status reporting in most modern instruments. Figure 5B-12 shows an overview of
the complete status register structure.
•
The Standard Event Register reports the standardized IEEE 488.2 errors and
conditions.
•
The Questionable Data Register reports when the output data from the Instrument
may not be trusted.
•
The Operational Data Register reports what events are in operation.
•
The Status Byte contains eight bits. Each bit shows if there is information to be
fetched in the above described registers and queues of the status structure.
Using the Registers
Each status register monitors several conditions at once. If something happens to any one
of the monitored conditions, a summary bit is set true in the Status Byte Register.
Enable registers are available so that you can select what conditions should be reported in
the status byte, and what bits in the status byte should cause SRQ.
A register bit is TRUE, i.e., something has happened, when it is set to 1. It is FALSE
when set to 0.
Note that all event registers and the status byte record positive events. That is when a
condition changes from inactive to active, the bit in the event register is set true. When
the condition changes from active to inactive, the event register bits are not affected at
all.
When reading the contents of a register, the Instrument answers with the decimal sum of
the bits in the register.
Example:
The Instrument answers 40 when you ask for the contents of the Standard Event Status
Register. Convert this to binary form. It will give you 101000.
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Bit 5 is true showing that a command error has occurred.
•
Bit 3 is also true, showing that a device dependent error has occurred.