SR850 lock-in amplifier module

Stanford Research Systems SR850 DSP Lock-In Amplifier

class place.plugins.sr850_amp.sr850_amp.SR850(config, plotter)

PLACE module for controlling the SRS SR850 lock-in amplifier.

config(metadata, total_updates)

Configure the amplifier.

Typically, the amplifier will be configured at the beginning of an experiment, so the majority of the activity will happen in this method.

Parameters:

• metadata (dict) – metadata for the experiment
• total_updates (int) – the number of update steps that will be in this experiment

update(update_number)

Perform updates to the amplifier during an experiment.

All settings are set during the config phase, so this method does not currently do anything.

Parameters:update_number (int) – the current update count

cleanup(abort=False)

Cleanup the amplifier.

Nothing to cleanup.

Parameters:abort (bool) – indicates the experiment is being aborted rather than having finished normally

Basic driver functions for the SR850

class place.plugins.sr850_amp.sr850_driver.SR850Driver(serial_port)

Lower level access to the lock-in amp settings

Reference and phase commands for the SR850 lock-in amplifier

class place.plugins.sr850_amp.sr850_ref_phase.SR850ReferenceAndPhaseCmds(serial_port)

Reference and phase commands

phas(shift=None)

Set or query the reference phase shift.

Parameters:shift (float or None) – phase (real number of degrees) rounded to 0.001 deg, between -360 and 719.999 (will be wrapped around at +/- 180 deg. Returns:if shift is None, then returns the current shift value Return type:float or None

fmod(source=None)

Queries and returns reference source.

Parameters:source (str or None) – the reference source: “internal”, “internal sweep”, or “external” Returns:if source is None, then returns the current source Return type:str or None Raises:ValueError – if source value is invalid

freq(frequency=None)

Sets the frequency of the internal oscillator.

Only allowed when reference source is internal.

Parameters:frequency (float or None) – frequency in Hz. Rounded to 5 digits or 0.0001 (whichever is greater). Range 0.001 to 102000. If harmonic number > 1, range harmonic number*f <= 102 kHz. Returns:if frequency is None, then returns the current frequency Return type:float or None

swpt(sweep=None)

Sets the type of frequency sweep.

Must be in internal sweep mode.

Parameters:sweep (str or None) – “linear” or “logarithmic” Returns:if sweep is None, returns the current sweep Return type:str or None Raises:ValueError – if sweep value is invalid

sllm(start=None)

Sets the starting frequency of internal frequency sweep.

Parameters:start (float or None) – frequency in Hz (rounded to 5 digits or 0.0001 Hz, whichever is greater. Range 0.001 to 102000 Hz. If harmonic number > 1, range harmonic number*f <= 102 kHz. Returns:if start is None, returns the current starting frequency Return type:float or None

sulm(stop=None)

Sets the stop frequency of internal frequency sweep.

Parameters:stop (float or None) – frequency in Hz (rounded to 5 digits or 0.0001 Hz, whichever is greater. Range 0.001 to 102000 Hz. If harmonic number > 1, range harmonic number*f <= 102 kHz. Returns:if stop is None, returns the current stop frequency Return type:float or None

rslp(slope=None)

Sets reference slope when using external reference mode.

At frequencyies < 1 Hz, a TTL reference must be used.

Parameters:slope (str or None) – “sine zero crossing”, “TTL rising edge”, or “TTL falling edge” Returns:if slope is None, returns the current slope Return type:str or None Raises:ValueError – if the slope value is invalid

harm(harmonic=None)

Sets the detection harmonic.

Parameters:harmonic (int or None) – an integer from 1 to 32767. Sets the lock-in to detect at the i^(th) harmonic of the reference frequency. Range i*freq < 102 kHz. If detection frequency > 102 kHz, harmonic number will be set to largest value in this range. Returns:if harmonic is None, returns the current setting Return type:int or None

slvl(amplitude=None)

Sets the amplitude of sine output.

Parameters:amplitude (float or None) – a voltage (Volts). Range 0.004 to 5.000, will be rounded to 0.002V. Returns:if amplitude is None, returns the current setting Return type:float or None

Input and filter commands for the SR850 lock-in amplifier

class place.plugins.sr850_amp.sr850_input_filter.SR850InputFilter(serial_port)

Input and filter commands for the SR850 lock-in amplifier

isrc(source=None)

Sets input configuration.

Parameters:source (str or None) – “A”, “A-B”, or “I” Returns:if source is None, returns the current setting Return type:str or None Raises:ValueError – if source value is invalid

igan(gain=None)

Sets conversion gain of current input.

Only relavent if input configured to measure current.

Parameters:gain (str or None) – “1 Mohm”, or “100 Mohm” Returns:if gain is None, returns the current setting Return type:str or None Raises:ValueError – if gain value is invalid

ignd(grounding=None)

Sets shield grounding.

Parameters:grounding (str or None) – “Float”, or “Ground” Returns:if grounding is None, returns the current setting Return type:str or None Raises:ValueError – if grounding value is invalid

icpl(coupling=None)

Sets input coupling.

Parameters:coupling (str or None) – “AC”, or “DC” Returns:if coupling is None, returns the current setting Return type:str or None Raises:ValueError – if coupling value is invalid

ilin(filters=None)

Sets input line notch filter.

Parameters:filters (str or None) – “Out or no filters”, “Line notch in”, “2x Line notch in”, or “Both notch filters in” Returns:if filters is None, returns the current setting Return type:str or None Raises:ValueError – if filters value is invalid

Gain and time constant commands

class place.plugins.sr850_amp.sr850_gain_time.SR850GainTime(serial_port)

Gain and time constant commands

sens(sensitivity)

Sets sensitivity

rmod(mode=None)

Sets or queries reserve mode.

rsrv(reserve=None)

Sets or queries dynamic reserve.

Sets or queries dynamic reserve to i^(th) available reserve (between 0 and 5). Must be in Manual reserve mode 0 (minimum reserve for present sensitivity and time constant 1 (next highest reserve) … 5 (always sets reserve to max.) Reserve increases by 10 dB for each successive value of i.

oflt(timeconst=None)

Sets time constant.

ofsl(slope=None)

Sets low pass filter slope.

sync(filter_status=None)

Sets synchronous filter status.

Only turned on if detection frequency < 200 Hz.

• 0 (off)
• 1 (synchronous filter below 200 Hz)

Output and offset commands

class place.plugins.sr850_amp.sr850_output_offset.SR850OutputOffset(serial_port)

Output and offset commands

fout(channel_str, quantity_str=None)

Sets front panel output sources.

oexp(output, offset=None, expand=None)

Sets output offset and expand.

If offset and expand parameters are both None, then this method returns the current offset and expand for the given output.

Otherwise, this method will set the parameters based on the arguments provided.

Parameters:

• output (str) – the output to be set or queried (‘X’, ‘Y’, or ‘R’)
• offset (float) – the offset in percent (-105.00 <= offset <= 105.00)
• expand (int) – the expand value (1 <= expand <= 256)

Returns:

the current offset and expand values for the output, or None if offset or expand are not None

Return type:

(float, int) or None

Raises:

ValueError – if a given argument is invalid

aoff(output)

Automatically sets X, Y, or R offset to zero.

Equivalent to pressing the Auto softkey in the Offset & Expand menu box. This method does not allow query.

Parameters:output (str) – the output to be set or queried (‘X’, ‘Y’, or ‘R’) Raises:ValueError – if a given argument is invalid

Trace and scan commands

class place.plugins.sr850_amp.sr850_trace_scan.SR850TraceScan(serial_port)

Trace and scan commands

trcd(trace_number, j_value=None, k_value=None, l_value=None, store=None)

Sets or queries the trace definitions.

The valid strings for j, k, and l are as shown here:

j,k,l

• 1
• X
• Y
• R
• theta
• Xn
• Yn
• Rn
• Al1
• Al2
• Al3
• Al4
• F

l only

• X^2
• Y^2
• R^2
• theta^2
• Xn^2
• Yn^2
• Rn^2
• Al1^2
• Al2^2
• Al3^2
• Al4^2
• F^2

For example, for following command defines trace 1 as X*Y/R and stores trace 1:

SR850TraceScan().trcd(1, 'X', 'Y', 'R', store=True)

The following command is used to query the current settings for trace 1:

j, k, l, stored = SR850TraceScan().trcd(1)

In this example, j, k, and l will be string values and stored with be a boolean value.

Parameters:

• trace_number (int) – selects the trace number (1, 2, 3, or 4) and is required
• j_value (str) – defines the trace as quantity j times quantity k divided by quantity l
• k_value (str) – defines the trace as quantity j times quantity k divided by quantity l
• l_value (str) – defines the trace as quantity j times quantity k divided by quantity l
• store (bool) – trace is stored or not stored

Returns:

Nothing or current settings

Return type:

(str, str, str, bool) or None

Raises:

ValueError – if provided values are found to be invalid

srat(sample_rate=None)

Sets or queries the scan sample rate.

Sample rates

• 62.5 mHz
• 125 mHz
• 250 mHz
• 500 mHz
• 1 Hz
• 2 Hz
• 4 Hz
• 8 Hz
• 16 Hz
• 32 Hz
• 64 Hz
• 128 Hz
• 256 Hz
• 512 Hz
• Trigger

Parameters:sample_rate (str) – the scan sample rate Returns:Nothing or current setting Return type:str or None

slen(length=None)

Sets scan length.

Set to closest allowed time given sample rate and stored number of traces. Max is buffer size / sample rate. Min is 1.0 sec.

This method does not validate the input data, but will query the device settings and return them in case validating the setting is desired by the user.

Parameters:length (float) – the scan length Returns:the scan length returned from the device Return type:float

send(mode=None)

Sets or queries the scan mode.

Parameters:mode (str) – the scan mode (either ‘1 shot’ or ‘loop’) Returns:the current scan mode or nothing Return type:str or None

trig()

Software trigger command.

Display and scale commands

class place.plugins.sr850_amp.sr850_display_scale.SR850DisplayScale(serial_port)

Display and scale commands

ascl()

Auto scale the active display.

This is just like pressing the (AUTO SCALE) key. Only Bar and Chart displays are affected.

adsp(display=None)

Select the active display.

The selected display must be presently displayed on the screen otherwise an error will result.

Parameters:display (str) – ‘Full’, ‘Top’, or ‘Bottom’ Returns:the current display Return type:str

smod(format_=None)

Sets or queries the screen format.

Parameters:format (str) – ‘Single’ (full screen) or ‘Up/Down’ (dual display) Returns:the current format Return type:str

mntr(mode=None)

Sets or queries the monitor display mode.

Parameters:mode (str) – ‘Settings’ or ‘Input/Output’ Returns:the current mode Return type:str

dtyp(display, type_=None)

Sets or queries the display type.

Warning

Unexpected behavior may occur if tryng to set the display type of a display that is not on screen.

Parameters:

• display (str) – ‘Full’, ‘Top’, or ‘Bottom’
• type (str) – ‘Polar’, ‘Blank’, ‘Bar’, or ‘Chart’

Returns:

the current type

Return type:

str

dtrc(display, trace=None)

Sets or queries the displayed trace number.

Warning

Unexpected behavior may occur if tryng to set the trace of a display that is not on screen.

Parameters:

• display (str) – ‘Full’, ‘Top’, or ‘Bottom’
• trace (int) – the trace number (1, 2, 3, or 4)

Returns:

the trace number

Return type:

int

dscl(display, range_=None)

Sets or queries the display range

Warning

Unexpected behavior may occur if tryng to set the display range of a display that is not on screen.

Parameters:

• display (str) – ‘Full’, ‘Top’, or ‘Bottom’
• range (float) – the display range (real number in units of displayed trace)

Returns:

the display range

Return type:

float

doff(display, center=None)

Sets or queries the display center value or offset

Warning

Unexpected behavior may occur if tryng to set the center of a display that is not on screen.

Parameters:

• display (str) – ‘Full’, ‘Top’, or ‘Bottom’
• center (float) – the display center (real number in units of displayed trace)

Returns:

the display center

Return type:

float

dhzs(display, scale=None)

Sets or queries the display horizontal scale.

Valid scales:

time/div

• 2 mS
• 5 mS
• 10 mS
• 20 mS
• 50 mS
• 0.1 S
• 0.2 S
• 0.5 S
• 1.0 S
• 2.0 S
• 5.0 S
• 10 S
• 20 S
• 50 S
• 1 min
• 100 S
• 2 min
• 200 S
• 5 min
• 500 S
• 10 min
• 1 kS
• 20 min
• 2 kS
• 1 hour
• 5 kS
• 2 hour
• 10 kS
• 3 hour
• 20 kS
• 50 kS
• 100 kS
• 200 kS

The minimum scale is related to the sample rate. The minumum scale is (1/sample rate) per division. This displays a minimum of 10 points on the chart. The maximum scale is also related to the sample rate. The scale cannot exceed that which would display the entire buffer on the chart at once.

Warning

Unexpected behavior may occur if tryng to set the scale of a display that is not on screen.

Parameters:

• display (str) – ‘Full’, ‘Top’, or ‘Bottom’
• scale (str) – the display scale

Returns:

the display scale

Return type:

str

rbin(display)

Queries the bin number at the right edge of the chart display.

The selected display must be a chart display.

This method along with cbin() can be used to position the time window of the active chart display over a specific trace region.

Parameters:display (str) – ‘Full’, ‘Top’, or ‘Bottom’ Returns:the bin number Return type:int

Cursor commands

class place.plugins.sr850_amp.sr850_cursor.SR850Cursor(serial_port)

Cursor commands

csek(mode=None)

Sets or queries the cursor seek mode.

Seek mode can either be ‘Max’, ‘Min’, or ‘Mean’. Each display has it’s own cursor seek mode. Use the atrc() or smod() methods to select the desired display. Only chart displays have a cursor.

Parameters:mode (str) – the seek mode to use Returns:the current seek mode Return type:str

cwid(width=None)

Sets or queries the cursor width of the active display.

Cursor width can either be ‘Off’, ‘Narrow’, ‘Wide’, or ‘Spot’. Each display has its own cursor width. Use the atrc() or smod() methods to select the desired display. Only chart displays have a cursor.

Parameters:width (str) – the cursor width to use Returns:the current cursor width Return type:str

cdiv(divisions=None)

Sets or queries the vertical divisions of the active display.

Vertical divisions can be 0, 8, or 10. Each display has its own vertical divisions mode. Use the atrc() or smod() methods to select the desired display. This only affects chart displays.

Parameters:divisions (int) – the vertical divisions to use Returns:the current vertical divisions for the active display. Return type:int

clnk(mode=None)

Sets or queries the cursor control mode.

Control mode can be ‘Linked’ or ‘Separated’. Only chart displays have a cursor.

Parameters:mode (str) – the cursor control mode to use Returns:the current cursor control mode Return type:str

cdsp(mode=None)

Sets or queries the cursor readout mode of the active display.

The readout mode can be ‘Delay’, ‘Bin’, ‘Fsweep’, or ‘Time’. Only chart displays have a cursor.

Parameters:mode (str) – the cursor readout mode to use Returns:the current readout mode Return type:str

cmax()

Move cursor to max or min of data.

This is just like pressing the CURSOR MAX/MIN key. Only effective if the active display is a chart display.

curs(display)

Queries the cursor position of the display.

Display can be ‘Full’, ‘Top’, or ‘Bottom’. The selected display must be a chart display.The returned values are those diaplyed in the cursor readout above the selected chart display.

Parameters:display (str) – the display to use Returns:the horizontal and vertical position Return type:(float, float)

cbin(position=None)

Sets or queries the cursor bin position of the active chart display.

The active display must be a chart display.

Remember that this method references the center of the cursor region.

Parameters:position (int) – the bin position to which the cursor should be moved Returns:the current bin posiiton Return type:int

Mark commands

class place.plugins.sr850_amp.sr850_mark.SR850Mark(serial_port)

Mark commands

mark()

Place a mark in the data buffer at the next sample.

This is the same as pressing the MARK key. This command has an effect only when a scan is in progress.

cnxt()

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cprv()

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mdel()

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mact()

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mbin()

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mtxt()

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Aux input and output commands

class place.plugins.sr850_amp.sr850_aux_input_output.SR850AuxInputOutput(serial_port)

Aux input and output commands

oaux()

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auxm()

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auxv()

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saux()

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tstr()

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Math commands

class place.plugins.sr850_amp.sr850_math.SR850Math(serial_port)

Math commands

smth(width)

Smooth the data trace of the active display.

This command may take some time to complete. If a scan is in progress, this method will pause the scan.

Parameters:width (str) – the smoothing width

copr(operation=None)

Sets or queries the type of math operation selected.

Parameters:operation (str) – the math operation Returns:the math operation Return type:str

calc()

Starts the calculation selected by copr().

This may take some time.

cagt(type_=None)

Sets or queries the argument type.

Parameters:type (str) – the argument type Returns:the argument type Return type:str

ctrc(trace=None)

Sets or queries the trace argument number.

The selected trace must be stored.

Parameters:trace (int) – the trace number Returns:the trace number Return type:int

carg(value=None)

Sets or queries the constant argument value.

Parameters:value (float) – the constant argument value Returns:the constant argument value Return type:float

ftyp(fit=None)

Sets or queries the type of fit.

Parameters:fit (str) – the type of fit Returns:the type of fit Return type:str

fitt(start, end)

Starts the fitting calculation.

The fit takes place between start% and end% and end must be larger than start. This fit may take some time. If a scan is in progress, it will be paused.

Parameters:

• start (int) – the start point from the left side of the screen (percentage)
• end (int) – the end point from the left side of the screen (percentage)

pars(parameter)

Queries the fit parameters after a curve fit has been performed.

If no fit has been performed or the selected parameter is unused in the fit, this could return invalid data.

Parameters:parameter (str) – the fit parameter Returns:the fit parameter value Return type:float

stat(start, end)

Starts the statistics calulations.

Only the data within the chart region defined between start% and end% (end must be larger than start) are analyzed. The analysis may take some time.

Parameters:

• start (int) – the start point from the left side of the screen (percentage)
• end (int) – the end point from the left side of the screen (percentage)

spar(statistic)

Queries the results of the statistical calculation.

If no analysis has been performed this will return invalid data.

Parameters:statistic (str) – the statistic parameter Returns:the result of the parameter Return type:float

Store and recall file commands

class place.plugins.sr850_amp.sr850_store_recall_file.SR850StoreRecallFile(serial_port)

Store and recall file commands

fnam(filename=None)

Sets or queries the active file name.

Parameters:filename (str) – the name of the file Returns:the name of the file Return type:str

sdat()

Saves the active display data trace.

This is the same as pressing the Data Save softkey.

sasc()

Saves the active disaply’s data trace in ascii format.

This is the same as pressing the Ascii Save softkey.

sset()

Saves the instrument setup.

This is the same as pressing the Settings Save softkey.

rdat()

Recalls the trace data, trace definition, and instrument state.

This is the same as pressing the Data Recall softkey.

rset()

Recalls the instrument setup.

This is the same as pressing the Setting Recall softkey.

Setup commands

class place.plugins.sr850_amp.sr850_setup.SR850Setup(serial_port)

Setup commands

outx(output)

Sets the output interface.

Note

The outx() method should be called before any query commands to direct the responses to the interface in use.

Parameters:output (str) – the interface to which data should be sent Returns:the interface currently being used Return type:str

ovrm(override=None)

kclk(click=None)

alrm(alarm=None)

thrs(hour=None)

Set or query the hours setting of the clock.

Parameters:hour (int) – the hour Returns:the hour Return type:int

tmin(minute=None)

Set or query the minutes setting of the clock.

Parameters:minute (int) – the minute Returns:the minute Return type:int

tsec(second=None)

Set or query the seconds setting of the clock.

Parameters:second (int) – the second Returns:the second Return type:int

dmth(month=None)

Set or query the month setting of the clock.

Parameters:month (int) – the month Returns:the month Return type:int

dday(day=None)

Set or query the day setting of the clock.

Parameters:day (int) – the day Returns:the day Return type:int

dyrs(year=None)

Set or query the year setting of the clock.

Parameters:year (int) – the year Returns:the year Return type:int

pltm(mode=None)

Set or query the plotter mode.

Parameters:mode (str) – the plotter mode interface Returns:the plotter mode interface Return type:str

pltb(baud_rate=None)

Set or query the RS232 plotter baud rate.

Parameters:baud_rate (int) – the communication baud rate Returns:the communication baud rate Return type:int

plta()

Not implemented

plts(speed=None)

Sets or queries the plot speed.

Parameters:speed (str) – the plot speed Returns:the plot speed Return type:str

pntr(pen=None)

Sets or queries the trace pen number.

Parameters:pen (int) – the trace pen number Returns:the trace pen number Return type:int

pngd(pen=None)

Sets or queries the grid pen number.

Parameters:pen (int) – the grid pen number Returns:the grid pen number Return type:int

pnal(pen=None)

Sets or queries the alphanumeric pen number.

Parameters:pen (int) – the alphanumeric pen number Returns:the alphanumeric pen number Return type:int

pncr(pen=None)

Sets or queries the cursor pen number.

Parameters:pen (int) – the cursor pen number Returns:the cursor pen number Return type:int

prnt(printer=None)

Sets or queries the printer type.

Parameters:printer (str) – printer type Returns:printer type Return type:str

Print and plot commands

class place.plugins.sr850_amp.sr850_print_plot.SR850PrintPlot(serial_port)

Print and plot commands

prsc()

pall()

ptrc()

pcur()

Data transfer commands

class place.plugins.sr850_amp.sr850_data_transfer.SR850DataTransfer(serial_port)

Data transfer commands

outp(channel)

outr(trace)

oaux(aux)

snap(parameters)

spts(trace)

trca(trace, start, num)

trcb()

trcl()

fast()

strd()

Interface commands

class place.plugins.sr850_amp.sr850_interface.SR850Interface(serial_port)

Interface commands

rst()

idn()

locl(state=None)

ovrm(override=None)

trig()

Status reporting commands

class place.plugins.sr850_amp.sr850_status_reporting.SR850StatusReporting(serial_port)

Status reporting commands

cls()

Clears all status registers.

The status enable registers are not cleared.

ese(register=None)

Sets or queries the standard event enable register.

Valid values for the register are 0-255.

Parameters:register (int) – the value the register should be set to Returns:the value of the register Return type:int

ese_bit(bit, value=None)

Sets or queries bits from the standard event enable register.

Valid bits are 0-7 and they can be set to either 0 or 1.

Parameters:

• bit (int) – the bit to change
• value (int) – the value for the bit

Returns:

the value of the bit (0 or 1)

Return type:

int

esr(bit=None)

sre(register=None)

Sets or queries the serial poll enable register.

Valid values for the register are 0-255.

Parameters:register (int) – the value the register should be set to Returns:the value of the register Return type:int

sre_bit(bit, value=None)

Sets or queries bits from the serial poll enable register.

Valid bits are 0-7 and they can be set to either 0 or 1.

Parameters:

• bit (int) – the bit to change
• value (int) – the value for the bit

Returns:

the value of the bit (0 or 1)

Return type:

int

stb(bit=None)

psc(value=None)

erre(bit=None, value=None)

errs(bit=None)

liae(bit=None, value=None)

lias(bit=None)