Standard Event Status Register - Lakeshore 642 User Manual

5.1.4.2 Status Register Sets
As shown in Figure 5-1, there are five register sets in the status system of the Model 642; Standard Event Status
Register, Operation Event Register, Hardware Error Status Register, Operational Error Status Register, and the Persistent
Switch Error Register.
5.1.4.2.1 Standard Event Status Register Set
The Standard Event Status Register reports the following interface related instrument events: power on detected,
command syntax errors, command execution errors, query errors, operation complete. Any or all of these events may be
reported in the standard event summary bit through the enable register, see Figure 5-2. The Standard Event Status Enable
command (*ESE) programs the enable register and the query command (*ESE?) reads it. *ESR? reads and clears the
Standard Event Status Register. The used bits of the Standard Event Register are described as follows:
Power On (PON), Bit (7) – This bit is set to indicate an instrument off-on transition.
Command Error (CME), Bit (5) – This bit is set if a command error has been detected since the last reading. This
means that the instrument could not interpret the command due to a syntax error, an unrecognized header,
unrecognized terminators, or an unsupported command.
Execution Error (EXE), Bit (4) – This bit is set if an execution error has been detected. This occurs when the
instrument is instructed to do something not within its capabilities.
Query Error (QYE), Bit (2) – This bit indicated a query error. It occurs rarely and involves loss of data because the
output queue is full.
Operation Complete (OPC), Bit (0) – When *OPC is sent, this bit will be set when the instrument has completed all
pending operations. The operation of this bit is not related to the *OPC? command which is a separate interface
feature. Refer to Paragraph 5.1.4.4.6 for more information.
Standard Event
7
Status Register
PON
*ESR?
AND
Standard Event
7
Status Enable
PON
*ESE, *ESE?
5-8
Lake Shore Model 642 Electromagnet Power Supply User's Manual
6 5 4 3
Not Not
CME EXE
Used Used
AND
AND
6 5 4 3
Not Not
CME EXE
Used Used
Figure 5-2. Standard Event Status Register
2 1 0 Bit
Not
QYE
OPC Name
Used
AND
AND
2 1 0 Bit
Not
QYE
OPC Name
Used
OR
To bit 5 (ESB) of
Status Byte Register
(See Figure 5-1.)
Computer Interface Operation