BK Precision VSP12010, Инструкция по эксплуатации

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BIT DEFINITIONS-SERVICE REQUEST ENABLE (SRE) REGISTER
BIT DESCRIPTION DECIMAL
VALUE DEFINITION
0 Not Used 1
Always write with 0.
1 Not Used 2
Always write with 0.
2
Questionable Data
4
If this bit is set, an SRQ will be raised
when one or more bits are set in the
Questionable Data register (bits must be
“enabled” in enable Register)
3 Not Used 8
Always write with 0.
4
Message Available
16
If this bit is written with ‘1’ then an SRQ is
raised when the data is available in the
Instrument’s output buffer.
5
Standard Event
32
If this bit is written with ‘1’ then an SRQ is
raised when one or more bits are Set in
the Standard Event register (bits must be
“enabled” in enable register).
6 64
Always write with 0.
7 Not Used 128
Always write with 0.
The Service Request Enable (SRE) register is cleared when:
*
You turn on the power to the instrument.
* You execute a *SRE 0 command.
ENABLING THE SRQ GENARATION:
First use the Service Request Enable ( SRE ) Register to select which
summary Bits of the Status Byte Register will set the low-level IEEE-488 SRQ
Signal. Now write the correct data in the SRE register, for enabling the SRQ reason
in the Status Byte Register. For this the command *STB<SP><NR.DATA> can be
used.After that the query *SRE? Command will return the same value, which was
sent above. Now enable your BUS controller’s SRQ interrupt.
When the Status Byte Register “ REQUEST SERVICE “ bit (Bit 6) is set, an
IEEE-488 SRQ Interrupt message is automatically sent to the BUS controller. The
BUS controller may then POLL the instruments on the bus to identify which one of
the instruments has raised the SRQ. The controller asks all the instruments on the
BUS to place their SRQ message one by one. The one with Bit 6 SET in its Status
Byte Register has requested the SERVICE. Now controller may take necessary
action to service or cancel the SRQ. Reading the status byte using an IEEE-488
Serial Poll only clears the “REQUEST SERVICE” bit or by reading the Event Register
whose Summary Bit (in the Status Byte) is causing the service request.
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