Serial Poll (Gpib Only); Query By Means Of Commands; Error-Queue Query; Resetting Values Of The Status Reporting System - Fluke Norma 4000 User Manual

Indicating the end of an averaging cycle by an SRQ via bit 10 in the STATus OPERation
Register. While waiting for the SRQ the program may perform other tasks.
•
Set bit 7 in the SRE (summary bit of STATus:OPERation Register)
•
Set bit 10 in the STATus:OPERation:ENABle Register (Averaging)
•
Set bit 10 in the STATus:OPERation:NTRansition to ensure that the transition of
averaging bit 10 from 1 to 0 (Averaging) is also stored in the EVENt register.
Calling up the *CLS command causes all bits of the NTRansition and
PTRansition to be set to 1 so that any bit change is recorded. Enabling the enable
bit, in this case bit 10, will normally be sufficient.
After having completed the averaging cycle, the instrument generates an SRQ.

Serial Poll (GPIB only)

In a serial poll, just as with command "*STB?," the status byte of an instrument is
queried. However, the query is realized via interface messages and is faster. The serial-
poll method has already been defined in IEEE 488.1 and used to be the only standard
possibility for different instruments to poll the status byte. The method also works with
instruments that do not adhere to SCPI or IEEE 488.2.
The VISA function for executing a serial poll is viReadSTB. Serial poll is mainly used to
obtain a fast overview of the state of several instruments connected to the IEC bus
(GPIB).

Query by Means of Commands

Each part of every status register can be read by means of queries. The individual
commands are indicated in the detailed description of the status registers above. What is
returned is always a number that represents the bit pattern of the register queried.
Evaluating this number is effected by the controller program.
Queries are usually used after an SRQ in order to obtain more detailed information on the
cause of the SRQ.

Error-Queue Query

Each error state in the instrument leads to an entry in the error queue. The entries of the
error queue are detailed plain-text error messages that can be looked at in the ERROR
menu via manual control or queried via the IEC bus using the "SYSTem:ERRor?"
command. Each call of "SYSTem:ERRor?" provides an entry from the error queue. If no
error messages are stored there any more, the instrument responds with 0, "No error."
The error queue should be queried after every SRQ in the controller program as the
entries describe the cause of an error more precisely than the status registers. Especially
in the test phase of a controller program the error queue should be queried regularly since
faulty commands from the controller to the instrument are recorded there as well.

Resetting Values of the Status Reporting System

Table 2-7 lists the different commands and events causing the status reporting system to
be reset. None of the commands, except for *RST and SYSTem:PRESet influences the
functional instrument settings. In particular, DCL does not change the instrument settings.
Event
Switching on
Table 2-7. Resetting Instrument Functions
DCL,SDC
Status Reporting System
Application of the Status Reporting System
*RST
2
*CLS
2-11