Lakeshore 336, User Manual

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6.2.5 Status System Detail: Status Register Sets 99
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6.2.4.8 Clearing Registers
The methods to clear each register are detailed in TABLE 6-3.
6.2.5 Status System
Detail: Status Register
Sets As shown in FIGURE 6-1, there are two register sets in the status system of the
Model 336: Standard Event Status Register and Operation Event Register.
6.2.5.1 Standard Event Status Register Set
The Standard Event Status Register reports the following interface related instru-
ment 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 (FIGURE 6-2). 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:
D
Power On (PON), Bit (7): this bit is set to indicate an instrument off-on
transition.
D
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 termina-
tors, or an unsupported command.
D
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.
D
Query Error (QYE), Bit (2): this bit indicates a query error. It occurs rarely and
involves loss of data because the output queue is full.
D
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
(section 6.2.6.6).
Register Method Example
Condition registers None. Registers are not latched —
Event registers:
Standard event status register
Operation event register
Query the event register
*ESR? (clears Standard Event
Status Register
Send *CLS *CLS (clears both registers)
Power on instrument —
Enable registers
Standard Event Status Enable Register
Operation Event Enable Register
Service Request Enable Register Write 0 to the
enable register
*ESE 0 (clears Standard Event
Status Enable register)
Power on instrument —
Status byte There are no commands that directly clear the status byte as the bits are
non-latching; to clear individual summary bits clear the event register that
corresponds to the summary bit—sending *CLS will clear all event
registers which in turn clears the status byte
If bit 5 (ESB) of the status byte is
set, send *ESR? to read the
standard event status register
and bit 5 will clear
Power on instrument —
TABLE 6-3 Register clear methods