LTSpice_RawRead module

From Nuno Brum’s PyLTSpice project: https://github.com/nunobrum/PyLTSpice

A pure python implementation of an LTSpice RAW file reader.

The reader returns a class containing all the traces read from the RAW File.

In case there there stepped data detected, it will try to open the simulation LOG file and read the stepping information.

Traces are accessible by the method <LTSpiceReader instance>.get_trace(trace_ref) where trace_ref is either the name of the net on the LTSPice Simulation. Normally trace references are stored with the format V(<node_name>) for voltages or I(device_reference). For example V(n001) or I(R1) or Ib(Q1).

For checking step, the method <LTSpiceReader instance>.get_steps() is used. In case there are no steps in the simulation, the class will return a single element list.

NOTE: This module tries to import the numpy if exists on the system.

If it finds numpy all data is later provided as an array. If not it will use a standard list of floats.

Classes:

Axis(name, datatype, datalen[, numerical_type])	This class is used to represent the horizontal axis like on a Transient or DC Sweep Simulation.
DataSet(name, datatype, datalen[, …])	Class for storing Traces.
DummyTrace(name, datatype)	Dummy Trace for bypassing traces while reading
LTSpiceRawRead(raw_filename[, traces_to_read])	Class for reading LTSpice wave Files.
Op(name, datatype, datalen, axis[, …])	Class used for storing operation points.
RawRead	This section is for testing your code
Trace(name, datatype, datalen, axis[, …])	Class used for storing generic traces that report to a given Axis.

Exceptions:

LTSPiceReadException

Custom class for exception handling

class LTSpice_RawRead.Axis(name, datatype, datalen, numerical_type='real')

Bases: LTSpice_RawRead.DataSet

This class is used to represent the horizontal axis like on a Transient or DC Sweep Simulation.

Methods:

_set_steps(step_info)
get_time_axis([step])
get_wave([step])
step_offset(step)

_set_steps(step_info)

get_time_axis(step=0)

get_wave(step=0)

step_offset(step)

class LTSpice_RawRead.DataSet(name, datatype, datalen, numerical_type='real')

Bases: object

Class for storing Traces.

Methods:

get_len()
get_point(n)
get_wave()
set_pointA(n, value)	function to be used on ASCII RAW Files.
set_pointB16(n, value)
set_pointB4(n, value)	Function that converts a normal trace into float on a Binary storage.
set_pointB8(n, value)	Function that converts the variable 0, normally associated with the plot X axis.

get_len()

get_point(n)

get_wave()

set_pointA(n, value)

function to be used on ASCII RAW Files.

Parameters

• n – the point to set

• value – the Value of the point being set.

set_pointB16(n, value)

set_pointB4(n, value)

Function that converts a normal trace into float on a Binary storage. This codification uses 4 bytes. The codification is done as follows:

.	7	6	5	4	3	2	1	0
Byte3	SGM	SGE	E6	E5	E4	E3	E2	E1	SGM - Signal of Mantissa: 0 - Positive 1 - Negative
Byte2	E0	M22	M21	M20	M19	M18	M17	M16	SGE - Signal of Exponent: 0 - Positive 1 - Negative
Byte1	M15	M14	M13	M12	M11	M10	M9	M8	E[6:0] - Exponent
Byte0	M7	M6	M5	M4	M3	M2	M1	M0	M[22:0] - Mantissa.

set_pointB8(n, value)

Function that converts the variable 0, normally associated with the plot X axis. The codification is done as follows:

.	7	6	5	4	3	2	1	0
Byte7	SGM	SGE	E9	E8	E7	E6	E5	E4	SGM - Signal of Mantissa: 0 - Positive 1 - Negative
Byte6	E3	E2	E1	E0	M51	M50	M49	M48	SGE - Signal of Exponent: 0 - Positive 1 - Negative
Byte5	M47	M46	M45	M44	M43	M42	M41	M40	E[9:0] - Exponent
Byte4	M39	M38	M37	M36	M35	M34	M33	M32	M[51:0] - Mantissa.
Byte3	M31	M30	M29	M28	M27	M26	M25	M24
Byte2	M23	M22	M21	M20	M19	M18	M17	M16
Byte1	M15	M14	M13	M12	M11	M10	M9	M8
Byte0	M7	M6	M5	M4	M3	M2	M1	M0

class LTSpice_RawRead.DummyTrace(name, datatype)

Bases: object

Dummy Trace for bypassing traces while reading

Methods:

set_pointA(n, value)
set_pointB16(n, value)
set_pointB4(n, value)
set_pointB8(n, value)

set_pointA(n, value)

set_pointB16(n, value)

set_pointB4(n, value)

set_pointB8(n, value)

exception LTSpice_RawRead.LTSPiceReadException

Bases: Exception

Custom class for exception handling

class LTSpice_RawRead.LTSpiceRawRead(raw_filename, traces_to_read='*', **kwargs)

Bases: object

Class for reading LTSpice wave Files. It can read all types of Files. If stepped data is detected, it will also try to read the corresponding LOG file so to retrieve the stepped data.

Methods:

_load_step_information(filename)
get_raw_property([property_name])	Get a property.
get_steps(**kwargs)
get_time_axis([step])	This funcion is to workaround on a LTSpice issue when using 2nd Order compression, where some values have a negative value
get_trace(trace_ref)	Retrieves the trace with the name given.
get_trace_names()

Attributes:

header_lines

_load_step_information(filename)

get_raw_property(property_name=None)

Get a property. By default it returns everything

get_steps(**kwargs)

get_time_axis(step=0)

This funcion is to workaround on a LTSpice issue when using 2nd Order compression, where some values have a negative value

get_trace(trace_ref)

Retrieves the trace with the name given.

get_trace_names()

header_lines = ['Title', 'Date', 'Plotname', 'Output', 'Flags', 'No. Variables', 'No. Points', 'Offset', 'Command', 'Variables', 'Backannotation']

class LTSpice_RawRead.Op(name, datatype, datalen, axis, numerical_type='real')

Bases: LTSpice_RawRead.Trace

Class used for storing operation points.

LTSpice_RawRead.RawRead

This section is for testing your code

alias of LTSpice_RawRead.LTSpiceRawRead Methods:

_load_step_information(filename)
get_raw_property([property_name])	Get a property.
get_steps(**kwargs)
get_time_axis([step])	This funcion is to workaround on a LTSpice issue when using 2nd Order compression, where some values have a negative value
get_trace(trace_ref)	Retrieves the trace with the name given.
get_trace_names()

Attributes:

header_lines

class LTSpice_RawRead.Trace(name, datatype, datalen, axis, numerical_type='real')

Bases: LTSpice_RawRead.DataSet

Class used for storing generic traces that report to a given Axis.

Methods:

get_point([n, step])
get_wave([step])

get_point(n=0, step=0)

get_wave(step=0)