The 34401A is the counterpart of the Keithley 2000 DMM. It has been in production for over a decade and sold under the HP brand as well as its successor Agilent and lastly, todays Keysight brand. It is an ubiquitous device of which either it or its Keithley equivalent can be found numerous times in companies which focus on electronics. As such, it would be highly desired to get it included in SweepMe for logging purposed.
Therefore, I created an appropiate driver based on the existing Keithley 2000 driver. Both instruments are sufficiently new to be based on standard SCPI commands. The modifications are therefore mainly restricted to adjusting the driver to the different capabilities and behaviours, e.g. how the RANGE command is applied for functions other than DC voltage and current or how the DISPLAY command is handled in terms of parameters.
The current driver supports Voltage/Current DC/AC, Resistance 2W/4W (Kelvin), Frequency, Period, Diode and Continuity. It has recently been discovered that the 34401A could be special ordered with a temperature capability and other options by US goverment/military institutions and that these features could be unlocked afterwards. Hoewever, as these are officially not supported by Keysight and I am not inclined to modify my own or one we have at work, I am not able to test this mode and therefore decided to exclude it from the driver for the time being.
As these units are often used to measure small but constant values, an 100 NPLC setting has been added in a way not to interfere with current terminology for the 0.1, 1 and 10 NPLC settings. I find the new terminology a great fitting but boring alternatives like “very slow” would also be OK 
My tests seem to suggest that the driver works flawless and might even deserve a higher than “beta” status. However, additional features could still be added to finetune some measurement behaviours plus I cannot check for the COM port functionallity as SweepMe just detects my internal COM1, neglecting my COM2 and COM3 ports on my PCI-e addon card but fails to get access even on said internal COM1, so the COM port option has to be checked later (maybe add this restriction into the driver description until it is taken care of?).
Best wishes,
Christian
# This Device Class is published under the terms of the MIT License.
# Required Third Party Libraries, which are included in the Device Class
# package for convenience purposes, may have a different license. You can
# find those in the corresponding folders or contact the maintainer.
#
# MIT License
#
# Copyright (c) 2020 Axel Fischer (sweep-me.net)
#
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
# SweepMe! device class
# Type: Logger
# Device: Keysight 34401A
from EmptyDeviceClass import EmptyDevice
class Device(EmptyDevice):
description = """<p><strong>Keysight 34401A</strong></p>
<p>DMM: Digital Multimeter</p>
<p> </p>
<p>The 34401A is a 6.5 digit DMM that supports measurement of voltage, current, resistance and frequency.</p>
<p>Two-wire as well as four-wire measurements are possible.</p>
<p>Temperature measurement was special order option and while there are ways to enable it, this driver does not currently support it.</p>
"""
def __init__(self):
EmptyDevice.__init__(self)
self.shortname = "Keysight34401A"
self.port_manager = True
self.port_types = ["COM", "GPIB"]
self.port_properties = {
"timeout": 10, #needed for 100 NPLC setting as it needs ~5s to compute
"EOL": "\r",
"baudrate": 9600, # factory default
}
# this dictionary connects modes to commands. The modes will be displayed to the user in the field 'Mode'
self.modes = {
"Voltage DC": "VOLT:DC",
"Voltage AC": "VOLT:AC",
"Current DC": "CURR:DC",
"Current AC": "CURR:AC",
"2W-Resistance": "RES",
"4W-Resistance": "FRES",
"Frequency": "FREQ",
"Period": "PER",
"Diode": "DIOD",
"Continuity": "CONT",
}
# this dictionary sets the unit of each mode
self.mode_units = {
"Voltage DC": "V",
"Voltage AC": "V",
"Current DC": "A",
"Current AC": "A",
"2W-Resistance": "Ohm",
"4W-Resistance": "Ohm",
"Frequency": "Hz",
"Period": "s",
"Continuity": "",
"Diode": "",
}
# a list of available resolutions as they can be sent to the instrument
self.resolutions = [
"0.1", # i.e., 100.0 V (3½ digits)
"0.01", # i.e., 10.00 V (3½ digits)
"0.001", # i.e., 1.000 V (3½ digits)
"0.0001", # i.e., 1.0000 V (4½ digits)
"0.00001", # i.e., 1.00000 V (5½ digits)
"0.000001", # i.e., 1.000000 V (6½ digits)
]
# a dictionary of trigger types and their corresponding commands. The trigger types will be shown in the GUI field 'Trigger'
self.trigger_types = {
"Immediate": "IMM",
# "Timer": "TIM",
# "Manual": "MAN",
"Internal": "BUS",
# "External": "EXT",
}
self.nplc_types = {
"Fast (0.1)" : 0.1,
"Medium (1.0)": 1.0,
"Slow (10.0)" : 10.0,
"Glacial (100.0)": 100.0,
}
def set_GUIparameter(self):
GUIparameter = {
"Mode" : list(self.modes.keys()),
#"Resolution": self.resolutions,
# "Range": ["1", "2"],
#"Channel": ["%i-%02d" % (S, CH) for S in range(1,3,1) for CH in range(1,11,1)],
#"Trigger": list(self.trigger_types.keys()),
#"Average": "1",
"NPLC": list(self.nplc_types.keys()),
"Range": ["Auto"],
"Display": ["On", "Off"],
}
return GUIparameter
def get_GUIparameter(self, parameter = {}):
#print()
#print(parameter)
self.mode = parameter['Mode']
#self.resolution = parameter['Resolution']
#self.clist = parameter['Channel'].replace(" ", "").replace("-", "").split(",")
#self.trigger_type = parameter['Trigger']
self.range = parameter['Range']
self.nplc = parameter['NPLC'].replace("(", "").replace(")", "").split()[-1]
self.display = parameter['Display']
self.port_string = parameter["Port"]
#average = int(parameter['Average'])
# here, the variables and units are defined, based on the selection of the user
# we have as many variables as channels are selected
self.variables = [self.mode] # we add the channel name to each variable, e.g "Voltage DC@1-03"
self.units = [self.mode_units[self.mode]]
self.plottype = [True] # True to plot data
self.savetype = [True] # True to save data
def initialize(self):
self.port.write("*IDN?")
print(self.port.read())
# once at the beginning of the measurement
self.port.write("*RST")
self.port.write("*CLS") # reset all values
self.port.write("SYST:BEEP:STAT OFF") # control-Beep off
## does not seem to work although it should: results in error -113 undefined header
#if self.port_string.startswith("COM"):
# self.port.write(":SYST:RWL")
def deinitialize(self):
self.port.write("SYST:BEEP:STAT ON") # control-Beep on
## does not seem to work although it should: results in error -113 undefined header
#if self.port_string.startswith("COM"):
# self.port.write("SYST:LOC") # RS-232/COM-port only
def configure(self):
# range = "0"
# channels = "(@" + ",".join(self.clist) + ")"
# print("Channels:", channels)
## Mode
self.port.write(":SENS:FUNC \"%s\"" % self.modes[self.mode])
## Speed
if not self.mode in ["Voltage AC", "Current AC", "Frequency", "Period", "Diode", "Continuity"]:
self.port.write(":SENS:%s:NPLC %s" % (self.modes[self.mode], str(self.nplc))) #NPLC only supported in DC Volts, DC Current, 2W- and 4W-Resistance
## Range
if not self.mode in ["Frequency", "Period", "Continuity", "Diode"]:
self.port.write(":SENS:%s:RANG:AUTO ON" % (self.modes[self.mode]))
## Display
if self.display == "Off":
self.port.write(":DISP 0")
def unconfigure(self):
if self.display == "Off":
self.port.write(":DISP 1") # We switch Display on again if it was switched off
def measure(self):
self.port.write("READ?") # triggers a new measurement
def call(self):
answer = self.port.read() # here we read the response from the "READ?" request in 'measure'
#print("Response to READ? command:", answer)
return [float(answer)]
"""
"""
