A-10
A1
A1.3.3 Variables and Channel Lists
SCPI variables are separated by a space from the last keyword in the SCPI com-
mand. The variables can be numeric values, boolean values or ASCII strings.
Numeric values are typically decimal numbers unless otherwise stated. When
setting or querying register values, the decimal variable represents the sum of
the binary bit weights for the bits with a logic '1' value. e.g. a decimal value
of 23 represents 16 + 4 + 2 + 1 or 0001 0111 in binary. Boolean values can be
either 0 or 1 or else OFF or ON. ASCII strings can be any legal ASCII character
between 0 and 255 decimal except for 10 which is the Linefeed character.
Channel lists are used as a way of listing multiple values. Channel lists are
enclosed in parenthesis and start with the ASCII '@' character. The values are
separated with commas. The length of the channel list is determined by the
unit. A range of values can be indicated by the starting and stopping values
separated by a colon.
(@1,2,3,4)
'
lists sequential values
(@ 1:4)
'
shows a range of sequential values
(@ 1,5,7,34)
'
lists random values
Figure A-4 Channel List Examples
A1.3.4 Error Reporting
SCPI provides a means of reporting errors by responses to the
SYST:ERR?
query. If the SCPI error queue is empty, the unit responds with 0, "No error"
message. The error queue is cleared at power turn-on, by a
*CLS
command
or by reading all current error messages. The error messages and numbers are
defined by the SCPI specification and are the same for all SCPI devices.
A1.3.5 Additional Information
For more information about SCPI refer to the SCPI Standard or to the SCPI
section in any SCPI compatible instrument manual.
