Don't use the "[SENS:]<mode>:RANGE..." request on Agilent protocol
speaking devices. Use "CONF:<mode> [<range>]" instead. This was tested
with all devices which reference this model.
In theory there is the question whether previously configured ranges
should be re-used when (exclusively) the MQ is switched. It's assumed
that this is not useful, instead users or their applications should
select the function first and optionally pick the range then. Re-use of
e.g. 10k resistance range when switching to capacitance might be seen as
confusing (and results in errors in the device).
Use the combination of INIT and FETCH? to get measurements. The READ?
request is more complex and might "undo" what INIT already initiated.
This improves perception of the 34405A meter's operation.
Rephrase the SCPI read timeouts in scpi-dmm model declarations. Shuffle
the order of product terms such that the milliseconds "unit" goes last,
and the milliseconds value goes first. Assume that "2500 * 1000 [us]"
better reflects the intention than "1000 * 2500" does.
While queries for the range are supported for voltage, current,
resistence, capacitance, the same queries in temperature, frequency,
diode, continuity modes not only fail but even lose the USB connection
to the device. This was consistently observed with 34405A and 34465A.
Suppress get and set range requests for the known problematic modes of
the Agilent protocol speaking meters.
Although the 34405A does not support this function, other Agilent
protocol using meters do (currently 34465A, very probably others which
are about to get added in the future).
It's assumed that announcing the availability of that MQ for a set of
meters while only some of them support it is preferrable over exploding
numbers of copies of tables which only slightly vary among each other.
This mechanical edit adds a flags field and the initializer element to
make the compiler happy. Behaviour does not change. See a word diff for
improved review experience.
Add support to get and set the auto/manual range on Agilent protocol
speaking devices (34405A, 34465A). The range values are mere numbers
without a unit or MQ associated with them. Support to list available
ranges is prepared but not used (not needed on these meters). Common
logic could open code the lists of ranges from the model description
if desired in a future implementation.
Though measurement values come in, the 34405A and 34465A meters kept
beeping when acquisition is started. Stopped beeping when the MEAS
keyword was changed to INIT, which is used for other Agilent devices
using the HP protocol variant.
This change is acceptable because it was tested on all DMMs which use
the Agilent protocol (according to scpi-dmm profiles).
Increase the default digit count in the 34465A model description. Though
most measurements get the precision from the current reading, this data
is used as a fallback when the response won't provide the detail.
Assume that *IDN? requests don't involve expensive processing, and thus
don't require *OPC? before their execution. This makes scpi-dmm follow
the good tradition to only use non-standard or model dependent features
after the device was successfully identified. Which avoids confusion on
unrelated devices.
Exclusively check for *OPC? availability on Owon devices, because these
motivated the introduction of the test in the first place. This avoids
confusion on other devices where short timeouts result in errors because
the response is not retrieved although the command is supported (observed
on Agilent meters connected via USBTMC).
The SCPI standard requires OPeration Complete command,
but some Owon meters do not implement it. This commit
makes the probe try OPC once, and if it gets no reply
it assumes it is not supported.
Add new command DMM_CMD_SETUP_LOCAL for setting device back
to "local" mode. If device implmements this command, it is
sent when driver is closed and after device "scan".
Define DMM_CMD_SETUP_LOCAL for GWInstek meters, so they get
returned to local mode automatically after use.
Any order is as arbitrary as any other. The alphabetical order of vendor
and model names might be the most robust during maintenance: easiest to
remember, easiest to use when checking for presence, and easiest to add
to or resolve conflicts during merges. Vendor renames (HP to Agilent to
Keysight, et al) are ugly but can't be helped easily.
Address minor style issues: Need not assign NULL after g_malloc0(), need
not check for NULL before g_free(). Rephrase diagnostics messages which
are user visible by default, remove internal development details. Reword
a few comments, and adjust their grammar for consistency across the code
base. The sr_analog_init() routine executed immediately before getting
measurements, need not (re-)assign endianess or floating point details,
except those which do change after initialization (double vs float).
Rephrase model dependent checks for easier adjustment during maintenance.
Unobfuscate string comparisons.
The current implementation of the SCPI DMM driver is conservative about
checking the device's being operational, but the *OPC? queries are found
in unfortunate locations. Run the OPC query right before running the
next "actual" command, not afterwards. And certainly not between sending
requests and potentially gathering responses in subsequent calls.
This commit does not change current behaviour, but improves maintenance
before pending commits.
The "get MQ" helper routine communicates SCPI responses and translates
them to internal "MQ and flag" values. Optionally return the MQ table
entry reference to callers, so they don't have to repeat the table
lookup when the function's default precision is required, or should
future "start acquisition" requests need to refer to the meter's current
function.
Supported SCPI DMM devices will differ in the set of options and whether
parameters can get queried or configured. Use a "generic" set of devopts
during scan and for simpler models, prepare support for other sets of
devopts for more complex models.
Implement the scpi-dmm driver in such a generic way that it could work
with several protocol variants and with differing models which happen to
use any of these protocol variants. Prepare a list of supported models
with their respective SCPI command set, set of DMM functions and their
precision.
Add support for Agilent 34405A. The ten functions of this device got
tested and are operational, in continuous mode as well as with sample
count or capture time limits. The driver can query the current meter's
function, can change the function, and can run acquisitions in either
the current mode or with a user specified function selection. There is
some potential for improvement: AUTO/MIN/MAX/HOLD indicators are not
supported by this implementation.
Gerhard Sittig
Petteri Aimonen
Timo Kokkonen
Mike Walters
Frank Stettner
Adrian Godwin
Mike Williams