Language Dictionary 27 *ESR? Meaning and Type Event Status Register Device Status Description This query reads the Standard Event Status Event register. Reading the register clears it. The bit configuration of this register is the same as the Standard Event Status Enable register (*ESE). See "Chapter 4 - Status Reporting" for a detailed explanation of this register. Query Syntax *ESR? Parameters (None) Returned Parameters (Register binary value) Related Commands *CLS *ESE *ESE? *OPC *IDN? Meaning and Type Identification System Interface Description This query requests the power supply to identify itself. It returns a string composed of four fields separated by commas. Query Syntax Returned Parameters *IDN? Field Information Hewlett-Packard Manufacturer xxxxA nnnnA-nnnnn 4-digit model number followed by a letter 10-character serial number or 0 .xx.xx Revision levels of firmware Example Hewlett-Packard,6681,0,A.00.01 Related Commands (None) *OPC Meaning and Type Operation Complete Device Status Description This command causes the interface to set the OPC bit (bit 0) of the Standard Event Status register when the power supply has completed all pending operations. (See *ESE for the bit configuration of the Standard Event Status register.) Pending operations are complete when: • All commands sent before *OPC have been executed. This includes overlapped commands. Most commands are sequential and are completed before the next command is executed. Overlapped commands are executed in parallel with other commands. Commands that affect output voltage, current or state, relays, and trigger actions are overlapped with subsequent commands sent to the power supply. The *OPC command provides notification that all overlapped commands have been completed. • Any change in the output level caused by previous commands has been completed (completion of settling time, relay bounce, etc.) • All triggered actions are completed *OPC does not prevent processing of subsequent commands, but Bit 0 will not be set until all pending operations are completed. Command Syntax *OPC Parameters (None) Related Commands *OPC? *WAI 28 Language Dictionary *OPC? Meaning and Type Operation Complete Device Status Description This query causes the interface to place an ASCII "1" in the Output Queue when all pending operations are completed. Pending operations are as defined for the *OPC command. Unlike *OPC, *OPC? prevents processing of all subsequent commands. *OPC? is intended to be used at the end of a command line so that the application program can then monitor the bus for data until it receives the "1" from the power module Output Queue. Do not follow *OPC? with *TRG or GPIB bus triggers. Such triggers sent after *OPC? will be prevented from executing and will prevent the power supply from accepting further commands. If this occurs, the only programmable way to restore operation is by sending the power supply a GPIB DCL (Device Clear) command. Query Syntax *OPC? Returned Parameters ASCII 1 is placed in the Output Queue when the power supply has completed operations. Related Commands *OPC *TRIG *WAI *OPT? Meaning and Type Option Identification Query Description This query requests the power supply to identify any options that are installed. Options are identified by number A. 0 indicates no options are installed. Query Syntax *OPT? Returned Parameters *PSC Meaning and Type Power-on Status Clear Device Initialization Description This command controls the automatic clearing at power turn-on of: • The Service Request Enable register. • The Standard Event Status Enable register. If the command parameter = 1, then the above registers are cleared at power turn-on. If the command parameter = 0, then the above registers are not cleared at power turn-on but are programmed to their last state prior to power turn on. This is the most common application for *PSC and enables the power module to generate an SRQ (Service Request) at power on. Command Syntax *PSC Parameters 0 | 1 | OFF | ON Example *PSC 0 *PSC 1 Query Syntax *PSC? Returned Parameters 0 | 1 Related Commands *ESE *SRE Language Dictionary 29 *PSC causes a write cycle to nonvolatile memory. If *PSC is programmed to 0, then the *ESE and *SRE commands also cause a write cycle to nonvolatile memory. The nonvolatile memory has a finite number of write cycles (see "Table 1-2, Supplementary Characteristics"). Programs that repeatedly write to nonvolatile memory can eventually exceed the maximum number of write cycles and may cause the memory to fail. *RCL Meaning and Type Recall Device State Recalling a previously stored state may place hazardous voltage at the power supply output. Description This command restores the power supply to a state that was previously stored in memory with a *SAV command to the specified location. The following states are recalled: CURR[:LEV][:IMM] OUTP[:STAT] OUTP:REL:POL CURR:PROT:STAT OUTP:PROT:DEL VOLT[:LEV][:IMM] DIG:DATA[:VAL] OUTP...
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