HP 54501A Programming Reference Manual page 103

*ESR
Table
5-2 shows
each bit in the Event
Status
Register and
its bit weight.
When you read the Event Status
Register, the value returned
is the total
bit weights of all bits that
are
high
at
the time you read the byte.
Table
5-2.
Standard Event
Status
Register
Bit
7
6
5
4
3
2
1
0
0
=
False
1
=
True
Bit
Weight
128
64
32
16
8
4
2
1
Bit
Name
PON
URQ
CME
EXE
DDE
QYE
RQC
OPC
Condition
1
=
an
OFF
to
ON
transition
has occurred
0
=
no
front-panel
key has been pressed
1
=
front-panel key
has been
pressed
0
=
no command errors
1
=
a
command error has been detected
0
=
no execution
error
1
=
an execution
error
has been detected
0
=
no device
dependent errors
1
=
a
device dependent error has
been detected
0
=
no query errors
1
= a
query error has been
detected
0
=
request control
-
NOT
used
-
always
0
0
=
operation
is
not complete
1
=
operation
is
complete
=
Low
=High
Common Commands
5-8
HP
54501A
Programming