Structure Of The Status Register; Common Commands; Program Commands - Hameg HMP4030 Handbuch

6.7

Structure of the status register

A status register exists as often as channels on the device
are available (e.g. HMP4030 = 3 channels = 3 status register).
Accordingly, the description text of the channel information
changes in Figure 6.1 (e.g. instrument 1 = channel 1, instrument
2 = channel 2 etc.).
Depending on the value of the read register con-
clusions on the current status of the device can
be drawn. For example, when the unit operates in
constant voltage, the result of the returned ISUM
register is a decimal "2", which corresponds the
binary value of "0000000000000010".
Any part of a status register system can be read by search
commands. A decimal value is returned and represents the
bit pattern of the requested register. Each SCPI register is 16
bits wide and has various functions. The individual bits are in-
dependent, i.e. each hardware status is assigned a bit number.
Bits 11-13 are still „free" resp. unused (always return a „0").
Certain areas of the registers are not used and can be used by
the resp. developer to fill with manufacturer specific functions.
The SCPI standard defines only the „basic functions". Some
devices offer an advanced functionality.
Bit 10 of the register only refers to the protection of the asso-
ciated channel, not to all. Each channel of the power supply is
considered as separate „instrument" (SCPI standard definition).
Therefore, the register „Status: Questionable: Instrument:
Isumarry" of the HMP4030 is also present three times (Isumma-
ry1-3). For more information, refer also to chapter 6.10 „Query
of the instrument status register".
6.8

Common Commands

Common commands are preceded by an asterisk (*). They are
special system commands, they are used without an indication
of paths. This is list of general SCPI commands:
*CLS Clear Status Command (= resets the status and the
listing of errors, erases the OPC state)
*ESE Event Status Enable Command (= sets the status of
the event register)
*ESE? Event Status Enable Query (= query of the event status
enable register)
*ESR? Event Status Register Query (= reads the value of the
event status register und resets it afterwards)
*IDN? Identification Query (= query of the instrument iden-
tification/ identity string)
*OPC Operation Complete Command (= sets the operation
complete register to its active status if all depending
operations have been completed)
*OPC? Operation Complete Query (= after all depending
operations are completed, the output will be a „1",
the OPC bit will not be set)
The HMP series does not support parallel proces-
sing of remote commands. If OPC? returns a „1",
the device is able to process new commands.
*RST Reset Command (= resets the instrument to its
original status)
*SRE Service Request Enable Command (= sets the service
request enable register )
*SRE? Service Request Enable Query (= query of the service
request enable register)
(see Fig. 6.2)
*STB?
*TST?
*WAI
*SAV {x} Save Command (= saves instrument setting {in x})
*RCL {x} Recall Command (= recalls instrument settings {from
6.9
A tree structure is used for the programming of the instrument.
The program commands contain all commands needed for the
control of the instrument. Paths are given following the rules
of the SCPI syntax. SCPI commands must be sent line by line,
i.e. each line has to be terminated by a Line feed or a Line Feed
+ Carriage Return. It is not allowed to concatenate commands
by a semicolon. Commands which cause an answer from the
instrument are called a query. This applies as well to queries
of the instrument status, parameters or limits. The commands
which ask for an immediate answer use a question mark (?).
Key words in parentheses ( ) may left out. The various levels
are marked with a colon (:). This indicates that the following
characters are elements of the level ROOT.
SCPI commands may be sent long or short. Long commands
use up to 12 characters (example: MEASure). Short commands
consist of the first 4 characters of the long command (example:
MEAS). If the 4th character happens to be a vowel and if these
4 characters are not the long command, the short command
will only consist of 3 characters (example: long = ARBitrary,
short = ARB).
The upper key characters are mandatory and they constitue
the short commands, the lower key characters are optional. It
is important to adhere to the prescribed formats of the SCPI
commands, except the short and long formats of the commands
all other formats are illegal. Upper or lower key characters
need not be observed. In this manual upper key characters are
used to indicate the short form commands, the long format is
indicated by the additional characters in lower ley.
Also make sure that the instrument generates readable data
which can be used by the listener (computer). Sources of errors
could be:
– instruments are switched off, cable loose, interface not
activated
– wrong instrument address
– false or incomplete strings of commands
– wrong measuring range
R e m o t e - C o n t r o l
The SRE is an enable register. Consequently, there
are no denotations about the bits. This register
conduce for the „OR" combination of the bits in the
status byte.
Read Status Byte Query (= query of the status byte
register)
Self-Test Query (= self-test query: error code)
Wait-to-Continue Command (= command which halts
the execution of a command string until preceding
commands have been executed)
x})

Program Commands

In order to prevent communication errors we
recommend not to use concatenation of commands
and to terminate each command by a line feed.
We recommend to start a program by *RST in order
to set the instrument to a defined status prior to
starting a program.
Subject to change without notice
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