Keithley configuration¶

Warning

Changing the range changes the analog out range -> take care to not run a scan in autorange.

Note

Changing the rate aka nplc does not affect the analog out.

Configuration¶

Model 6485 can be configured to terminate each message that it transmits with any of the following combinations of <CR> and <LF>:

LF line feed \n
CR carriage return \r
LFCR line feed, carriage return \n\r (to avoid…)
CRLF carriage return, line feed \r\n

To check and change the hardware configuration of the Keithley, follow the sequence:

press the config local button,
press the COMM button. You should see RS232 or GPIB. ( OR SHIFT + ZCHK/RS-232 button for the 6514 model )
with the help of the Δ / ∇ buttons (right most on the front panel) you could go through all the parameters and change them if needed.
to end the procedure press ENTER and then EXIT.

The instrument keeps the setup when switched off.

Minimum¶

plugin: keithley
keithleys:
  - model: 2000
    gpib:
      url: enet://gpibid11c.esrf.fr
      pad: 22
    sensors:
      - name: pico6
        meas_func: VOLT
        address: 1

  - model: 2000
    gpib:
      url: enet://gpibid11c.esrf.fr
      pad: 12
    sensors:
      - name: sample_temp #Temperature Sensor
        meas_func: TEMP
        address: 1
    nplc: 1 #(optional) 1 is the default for temperature
    measurement_resolution: 6 #number of digits (optional) (default: 6)
    thermocouple_type: J # Thermocouple type (J, K, or T) (optional) (default: J)

  - model: 6485
    gpib:
      url: enet://gpibid11c.esrf.fr
      pad: 23
    sensors:
      - name: pico7
        address: 1

Full¶

plugin: keithley
keithleys:
  - model: 6485
    auto_zero: False
    display: False
    gpib:
      url: enet://gpibid11c.esrf.fr
      pad: 22
    sensors:
      - name: pico6
        address: 1
        nplc: 0.1
        auto_range: False
    range: 2e-8
        zero_check: False
        zero_correct: False

plugin name (mandatory: keithley)
controller name (mandatory). Some controller settings are needed. To hook the settings to the controller we use the controller name. That is why it is mandatory
controller model (optional. default: discover by asking instrument *IDN) For “old” models talking DDC protocol, 485/486/487, one must set the model.
auto_zero enabled (optional, default: False)
display enabled (optional, default: True)
zero_check enabled (optional, default: False). Only for 6485 and 6487!
zero_correct enabled (optional, default: False). Only for 6485 and 6487!
controller URL (mandatory, valid: gpib, tcp, serial)
- gpib (mandatory: url and pad). See Gpib for list of options
- serial (mandatory: port). See Serial for list of options
- tcp (mandatory: url). See Tcp for list of options
list of sensors (mandatory)
sensor name (mandatory)
sensor address (mandatory). Valid values:
- model 6482: 1, 2
- model 6485: 1
- model 2000: 1
- model 2700: 1
- model 485: 1
- model 486: 1
- model 487: 1
sensor DC current nplc (optional, default: 0.1), not for 485/486/487 modeles.
sensor DC current auto_range (optional, default: False)
sensor DC current range, only mandatory if the auto_range is False, for supported values call the possible_ranges property.

parameters’ persistance¶

Some parameters (described below) are stored as settings. This means that the static configuration described above serves as a default configuration. The first time ever the system is brought to life it will read this configuration and apply it to the settings. From now on, the keithley object will rely on its settings. This is the same principle as it is applied on the bliss axis velocity for example.

The following controller parameters are stored as settings:

auto_zero
display
zero_check only for 6485 and 6487
zero_correct only for 6485 and 6487

The following sensor parameters are stored as settings:

nplc
auto_range
range

Usage¶

range¶

Keithley controllers have a set of measurement ranges. The range has to be adapted to the value to measure in order to improve measurement accuracy.

Valid ranges depend on controller model.

Example for a Keithley 6485:

DEMO [13]: nkiodet.range_available
 Out [13]: [2e-09, 2e-08, 2e-07, 2e-06, 2e-05, 0.0002, 0.002, 0.02]

To change the range of a Keithley, the range property has to be set to the value to measure. The BLISS controller will then choose the most adapted range (i.e.: the upper valid range)

Example:

DEMO [14]: nkiodet.range=0.003
nkiodet range set to 0.02

Warning

This behavior can produce strange situations: ```python DEMO [16]: nkiodet.range=0.0021 DEMO [17]: print(nkiodet.range) 0.021 # one zero seems lost but no, this range is requiered to measure 0.0021 value.

DEMO [19]: nkiodet.range=0.000000000000000000000021 nkiodet range set to 2e-09 # lower range is selected

DEMO [20]: nkiodet.range=0.1 nkiodet range set to 0.02 # higher range is selected

```