HP 54501A Programming Reference Manual page 73

TRG
•
trigger. Indicates whether
a
trigger
has been received.
LTF
-
limit
test
failure. Indicates whether
a
limit
test
failure has
occurred.
Key Features
A
few of the
most important features
of
Status Reporting
are
shown below.
Operation
Complete.
The
IEEE 488.2 structure provides one technique
which can be used to find out
if
any operation
is
finished.
The *OPC
command, when sent
to the instrument after the operation of
interest, will
set
the
OPC
bit in the Standard Event Status Register.
If
the
OPC bit and
the
RQS
bit
have
been enabled,
a
service request
will be generated.
OUTPUT
707;"*SRE
32; *ESE 1"
!enables an
OPC
service request
OUTPUT
707;":DIG CHAN1;
*OPC"
iinitiates data acquisition, and
!will generate
a
SRQ
when the
! acquisition
is complete
The Trigger Bit. The
TRG
bit indicates
if
the device
has received
a
trigger. The
TRG
event register will
stay set after receiving
a
trigger
until
it is
cleared by reading it or using the *CLS command. If
your application
needs to detect multiple triggers, the TRG event register must be cleared
after each one.
If
you are
using the Service Request to interrupt
a
program or controller
operation when the trigger bit is set, then you must clear the event register
after each time it
has been
set.
OUTPUT 707;"*SRE I"!
enables
a
trigger
service request.
!
the next trigger will generate an
SRQ.
OUTPUT 707;":TER?"! queries the
TRG
event register, thus
ENTER
707;A$! clearing
it.
!
the next trigger
can now generate an
!SRQ
Status Byte.
If
the
device
is requesting
service
(RQS
set), and the
controller serial polls the device, the RQS bit is
cleared.
The MSS
bit
(read
with
*STB?) will not be cleared by reading
it.
The
status
byte is
not
cleared when read, except for the
RQS
bit.
HP 54501A
Message Communication and System
Functions
Programming
3-31