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SHR 2020 configuration

The Iseg SHR HV supplies are High Precision two channels high voltage SMU (Source Measuring Units).

The Shr controller class (bliss.controllers.powersupply.shr) provides:

2 SoftAxis (pseudo-axes):

  • Output voltage setpoint on channel ‘A’ (using a ramp rate)

  • Output voltage setpoint on channel ‘B’ (using a ramp rate)

4 Counters:

  • Actual voltage on channel ‘A’ (tag: voltage)

  • Actual current on channel ‘A’ (tag: current)

  • Actual voltage on channel ‘B’ (tag: voltage)

  • Actual current on channel ‘B’ (tag: current)

Configuration example (yml)

- class: Shr
  module: powersupply.shr
  plugin: bliss
  name: shr
  tcp:
    url: id00-shr2220r:10001
    eol: "\r\n"
    timeout: 10

  counters:
    - counter_name: shr0_cv
      channel: A
      tag: voltage
      mode: SINGLE
    - counter_name: shr0_ci
      channel: A
      tag: current
      mode: SINGLE
    - counter_name: shr1_cv
      channel: B
      tag: voltage
      mode: SINGLE
    - counter_name: shr1_ci
      channel: B
      tag: current
      mode: SINGLE

  axes:
    - axis_name: shr0_hv
      channel: A
      tolerance: 10
      low_limit: 0
      high_limit: 250

    - axis_name: shr1_hv
      channel: B
      tolerance: 10
      low_limit: 0
      high_limit: 250

Presentation of the SHR controller

Display information about the controller by typing its name in the shell.

TEST_SESSION [2]: nhq
Gathering information from {'url': 'localhost:28319'}, please wait few seconds...

         Out [2]: === Controller nhq (sn481323 ver2.06) ===

                  Maximum voltage : 5000V
                  Maximum current : 2mA
                  Channel A state : ON @ -0.0V
                  Channel B state : ON @ 0.0V

The Nhq has two high voltage channels ‘A’ and ‘B’.

Display more information about each channel with the .chA and .chB properties.

TEST_SESSION [3]: nhq.chA
         Out [3]: === Channel 'A' ===

                  Control     : RS232
                  Polarity    : negative
                  HV-ON switch: ON
                  KILL-ENABLE : OFF
                  INHIBIT     : inactive

                  Status      : ON (Output voltage according to set voltage)
                  Voltage     : -0.0V     (limit=90.0%)
                  Current     : 0.0A      (limit=20.0%)
                  Setpoint    : 0.0V
                  Ramp rate   : 40.0V/s
                  Current trip: 300.0

Read the actual current and voltage values of a channel with:

TEST_SESSION [8]: nhq.chA.voltage                                                                                             
         Out [8]: 30.0
TEST_SESSION [9]: nhq.chA.current                                                                                             
         Out [9]: 0.000243

Set the output voltage to a target value (setpoint) with:

TEST_SESSION [9]: nhq.chA.setpoint=80

The device will ramp the voltage up to the setpoint value at a given ramping rate (V/s).

TEST_SESSION [12]: nhq.chA.ramprate                                                                                
         Out [12]: 40.0  
TEST_SESSION [7]: nhq.chA.status                                                                                          
         Out [7]: 'L2H'

The .status property of a channel (nhq.chA.status) provides information about the ramping:

  • ON: the actual voltage is equal to the voltage setpoint value (not ramping).

  • L2H: the actual voltage is increasing to the voltage setpoint value (ramping).

  • H2L: the actual voltage is decreasing to the voltage setpoint value (ramping).

  • TRP: the high voltage has been cut because the actual current exceeded the current trip value (ramping aborted).

Each channel can define a current_trip (e.g: nhq.chA.current_trip=600uA).

If the actual current exceed this value while ramping, the ramping is stopped and voltage set to zero.

If the communication with the NHQ hardware is too slow or unstable:

  • nhq.break_time: set the minimum time between 2 characters (hardware property).

  • nhq._comm_delay: set the wait delay between 2 successives commands.

Scanning with the NHQ

For each channel, the NHQ provides a pseudo axis for the high voltage output and 2 counters to read the actual voltage and current.

These objects are exported in the session using the counter_name and axis_name defined in the YML configuration file.

TEST_SESSION [16]: nhq.counters                                                                                              
         Out [16]: Namespace containing:
                   .iav
                   .iac
                   .ibv
                   .ibc

TEST_SESSION [18]: nhq.axes                                                                                                
         Out [18]: Namespace containing:
                   .oav
                   .obv

For example, the high voltage of channel ‘A’ can be scanned using the pseudo axis ‘oav’.

Between two points of the scan, the output voltage will be ramped using the actual ramprate.

In a scan command, counting on the NHQ will count on all four counters.

TEST_SESSION [15]: ascan(oav,40,80,4,1,nhq)                                                                                 
         Out [15]: Scan(number=38, name=ascan, path=/home/pguillou/tmp/scans/test_session/data.h5)

Scan 38 Tue Apr 21 11:19:18 2020 /home/pguillou/tmp/scans/test_session/data.h5 test_session user = pguillou
ascan oav 40 80 4 1

           #         dt[s]        oav[V]        iac[A]        iav[V]        ibc[A]        ibv[V]
           0             0            40      0.000122           -40             0             0
           1       5.99969            51      0.000152           -50             0             0
           2       12.0537            60      0.000184           -60             0             0
           3       18.3079            71      0.000213           -70             0             0
           4       24.4353            81      0.000243           -80             0             0

Took 0:00:35.375036

Using a Nhq channel as a Regulation output

The high voltage outputs of the NHQ can be used as an ExternalOutput of the Bliss Regulation framework.

A implementation of that class is already provided and can be imported like this:

- class: NhqOutput    
    module: powersupply.nhq
    plugin: bliss
    name: nhq_output_A
    device: $nhq.chA
    unit: V    
    ramprate: 10.0  #V/s     

TEST_SESSION [10]: na=config.get('nhq_output_A')      
TEST_SESSION [11]: na
         Out [11]:

    === ExternalOutput: nhq_output_A ===
    device: nhq.chA <bliss.controllers.powersupply.nhq.NhqChannel object at 0x7f1d4cfb8c50>
    current value: -40.000 V
    ramp rate: 10.0
    ramping: False
    limits: (None, None)