User Manual LW120
IEEE-STD-488.2
Common
Commands and
Queries
Since most instruments and devices in an ATE system use similar
commands that perform similar functions, the IEEE-STD-488.2
document has specified a common set of commands and queries that
all compatible devices must use. This avoids situations where devices
from various manufacturers use different sets of commands to enable
functions and report status. The IEEE-STD-488.2 treats common
commands and queries as device dependent commands. For
example, *TRG is sent over the bus to trigger the instrument. Some
common commands and queries are optional, but most of them are
mandatory.
The following is a complete listing of all common-commands and
queries, which are used by the LW120
*CLS
- Clear the Status Byte summary register and all event registers.
*ESE
<enable_value> - Enable bits in the Standard Event enable register.
The selected bits are then reported to the status byte.
*ESE?
- Query the Standard Event enable register. The generator returns
a decimal value, which corresponds to the binary-weighted sum of all bits,
set in the register.
*ESR?
- Query the Standard Event register. The generator returns a
decimal value, which corresponds to the binary-weighted sum of all bits,
set in the register.
*IDN?
- Query the generator’s identity. The returned data is organized into
four fields, separated by commas. The generator responds with its
manufacturer and model number in the first two fields, and may also report
its serial number and options in fields three and four. If the latter
information is not available, the device must return an ASCII 0 for each.
For example, Model LW120 response to *IDN? is:
LeCroy,LW120,0,1.0
*OPC
- Set the "operation complete" bit (bit 0) in the Standard Event
register after the previous commands have been executed.
*OPC?
- Returns "1" to the output buffer after all the previous commands
have been executed. *OPC? is used for synchronization between a
controller and the instrument using the MAV bit in the Status Byte or a
read of the Output Queue. The *OPC? query does not affect the OPC
Event bit in the Standard Event Status Register (ESR). Reading the
response to the
*OPC?
query has the advantage of removing the
complication of dealing with service requests and multiple polls to the
instrument. However, both the system bus and the controller handshake
are in a temporary hold-off state while the controller is waiting to read the
*OPC? query response.
*OPT?
- Returns the value “0” for a LW120 with no options. Returns “1” for
a Model LW120 with 4Meg memory and returns “2” for a Model LW120
Remote Programming Reference 4-60