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Remote Control
R&S
®
FPC
344
User Manual 1178.4130.02 ─ 07
19.17.2
Overview of the Status Registers
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
not used
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
reserved
reserved
reserved
POWer
reserved
FREQuency
reserved
reserved
reserved
LIMit
reserved
reserved
reserved
reserved
reserved
not used
0
1
2
3
4
5
6
7
Error Queue
Message Queue
+
0
1
2
3
4
5
6
7
Operation Complete
reserved
Query Error
Device Dependent Error
Execution Error
Command Error
reserved
Power On
+
+
& & & & & & & &
& & & & & & & &
7 6 5 4 3 2 1 0
7 6 5 4 3 2 1 0
PPE
SRE
≥
1
≥
1
IST Message
SRQ Message
STB
Operation Status
Event Status Register
+ Event Status Enable
QUEStionable Status
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
EXTernalREFerence
reserved
reserved
reserved
reserved
reserved
reserved
not used
+
QUEStionable:FREQuency
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
LIMit1 FAIL
LIMit2 FAIL
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
not used
+
QUEStionable:LIMit
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
reserved
reserved
IF_Overload
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
reserved
not used
+
QUEStionable:POWer
Figure 19-6: Overview of the status registers
19.17.3
Status Byte (STB) and Service Request Enable Register (SRE)
The
STB
is already defined in IEEE 488.2. It provides a rough overview of the instru-
ment status by collecting the pieces of information of the lower registers. It can thus be
compared with the
CONDition
part of an SCPI register and assumes the highest level
within the SCPI hierarchy. A special feature is that bit 6 acts as the sum bit of the
remaining bits of the status byte.
The
STATUS BYTE
is read using the command
*STB?
or a serial poll.
The
STB
is linked to the
SRE
. The latter corresponds to the
ENABle
part of the SCPI
registers in its function. Each bit of the
STB
is assigned a bit in the
SRE
. Bit 6 of the
SRE
is ignored. If a bit is set in the
SRE
and the associated bit in the
STB
changes from
0 to 1, a service request (SRQ) is generated, which triggers an interrupt in the control-
Status Reporting System