4 – 24
Remote Operation
Weight
Bit
Flag
1
0
undef (0)
2
1
undef (0)
4
2
undef (0)
8
3
undef (0)
16
4
undef (0)
32
5
ESB
64
6
MSS
128
7
undef (0)
ESB : Event Status Bit. Indicates whether one or more of the enabled
events in the Standard Event Status Register is true.
MSS : Master Summary Status. Indicates whether one or more of the
enabled status messages in the Status Byte register is true.
This register is read with the
*STB?
query.
4.5.2
Service request enable (SRE)
Each bit in the SRE corresponds one-to-one with a bit in the SB regis-
ter, and acts as a bitwise AND of the SB flags to generate MSS. Bit 6 of
the SRE is undefined—setting it has no e
ff
ect, and reading it always
returns 0. This register is set and queried with the
*SRE(?)
command.
At power-on, this register is cleared.
4.5.3
Standard event status (ESR)
The Standard Event Status Register consists of 8 event flags. These
event flags are all “sticky bits” that are set by the corresponding
events, and cleared only by reading or with the
*CLS
command.
Reading a single bit (with the
*ESR?
i
query) clears only Bit
i
.
Weight
Bit
Flag
1
0
OPC
2
1
undef (0)
4
2
QYE
8
3
DDE
16
4
EXE
32
5
CME
64
6
undef (0)
128
7
undef (0)
OPC : Operation Complete. Set by the
*OPC
command.
QYE : Query Error. Indicates data in the output queue has been lost.
DDE : Device-Dependent Error.
Indicates an internal command
queue overflow.
SR124
Analog Lock-In Amplifier
