Library

niveristand.library.abstime()

Returns the current date and time, in seconds, relative to the operating system’s epoc.

Note: Only available for RT sequences.

niveristand.library.arraysize(x)

Returns the number of elements in x, where x is an array.

Parameters

x – the array for which you want to get the number of elements.

Returns

the size of the array. If x is not an array, this function returns 0.

Return type

int

niveristand.library.clearfault(x)

Clears all faults set on channel x.

Parameters

x – the channel you want to clear faults on.

Channel x must be a reference to a channel and should not be a reference to a local variable. If channel references a local variable, clearfault() performs no operation.

Note: Only available for RT sequences.

niveristand.library.clearlasterror()

Clears the last error set by generate_error().

Note: Only available for RT sequences.

niveristand.library.deltat()

Returns the duration, in seconds, of the current system timestep.

To perform equality or comparison operations, use deltatus.

Note: In Python Mode, this function always returns 0.01 for a rate of 100Hz.

niveristand.library.deltatus()

Returns the duration, in microseconds, of the current system timestep.

Note: In Python Mode, this function always returns 10,000 for a rate of 100Hz.

niveristand.library.fault(channel, value)

Faults channel with value.

Parameters

• channel – channel to fault.

• value (float) – value to fault the channel.

channel must be a reference to a channel and should not be a reference to a local variable. If channel references a local variable, fault() performs no operation.

Note: Only available for RT sequences.

niveristand.library.fix(x)

Rounds x to the nearest integer between x and zero.

Parameters

x (float) – value you want to round.

Returns

floating-point representation of the rounded value.

Return type

(float)

Note: Only available for RT sequences.

niveristand.library.generate_error(code, message, action)

Generates an error to report test failure.

Parameters

• code (int) – error code to display.

• message (str) – error string to display.

• action (niveristand.clientapi.ErrorAction) – action to perform.

Returns

If action is Continue, returns the generated error.

niveristand.library.getlasterror()

Returns the numeric error code of the last error set by generate_error().

Note: Only available for RT sequences.

niveristand.library.iteration()

Returns the number of iterations since the current top-level sequence started.

Returns

iteration count.

Return type

int

niveristand.library.localhost_wait(amount=0.1)

Waits for channel values to update.

Parameters

amount (float) – time, in seconds, this function waits for channel values to update.

When running in the VeriStand Engine, this function is ignored as channels are always up to date.

niveristand.library.multitask()

Creates a multitask context for branching execution.

Refer to niveristand.library.multitask() for more details on branching execution.

niveristand.library.nivs_yield()

Yields execution from this task or block to the next.

Refer to niveristand.library.multitask() for more details on yielding to other tasks.

niveristand.library.quotient(x, y)

Returns floor(x/y), the number of times y evenly divides into x.

Parameters

• x – dividend.

• y – divisor.

Returns

integer quotient of x/y

Return type

int

niveristand.library.recip(x)

Returns 1/x.

Parameters

x – divisor.

Note: Only available for RT sequences.

niveristand.library.rand(x)

Returns a random floating-point number between 0 and the maximum value.

Parameters

x (float) – maximum value.

Returns

random number between 0 and x

Return type

float

niveristand.library.rem(x, y)

Returns the remainder of x/y, when the quotient is rounded to the nearest integer.

Parameters

• x (float) – dividend.

• y (float) – divisor.

niveristand.library.seqtime()

Returns the number of elapsed seconds since the epoch.

Returns

time, in seconds, since the epoch.

Return type

float

To perform equality or comparison operations, use seqtimeus instead.

niveristand.library.seqtimeus()

Returns the elapsed time, in microseconds, since the epoch.

Returns

elapsed time, in microseconds, as reported by the system clock.

Return type

int

niveristand.library.stop_task(task_function)

Stops the task you specify.

Parameters

task_function – task function you want to stop. You must have previously declared the task function inside a multitask() context.

Refer to niveristand.library.multitask() for more details on stopping tasks.

niveristand.library.task(mt)

Marks a nested function-definition as a task inside a niveristand.library.multitask().

Parameters

mt – the parent niveristand.library.multitask()

Use this function as a decorator. Refer to niveristand.library.multitask() for more details on using tasks.

niveristand.library.tickcountms()

Returns the current value of the milliseconds counter.

Returns

time, in milliseconds, as reported by the high-precision counter (if available).

Return type

int

niveristand.library.tickcountus()

Returns the current value of the microseconds counter.

Returns

time, in microseconds, as reported by the high-precision counter (if available).

Return type

int

niveristand.library.wait(duration)

Waits the duration, in seconds, you specify.

Parameters

duration (DoubleValue) – time, in seconds, this function waits. You may specify fractions of seconds.

Returns

actual seconds waited.

Return type

float

This wait is non-blocking, so other tasks will run while this wait executes.

niveristand.library.wait_until_next_ms_multiple(ms_multiple)

Waits until the next millisecond multiple of the number you specify in ms_multiple.

Parameters

ms_multiple (I64Value) – the millisecond multiple to wait until.

Returns

actual milliseconds waited.

Return type

int

This wait is non-blocking, so other tasks will run while this wait executes.

niveristand.library.wait_until_next_us_multiple(us_multiple)

Waits until the next microsecond multiple of the number you specify in us_multiple.

Parameters

us_multiple (I64Value) – the microsecond multiple to wait until.

Returns

actual microseconds waited.

Return type

int

This wait is non-blocking, so other tasks will run while this wait executes.

niveristand.library.wait_until_settled(signal, upper_limit, lower_limit, settle_time, timeout)

Waits until signal settles for the amount of time you specify in settle_time.

Parameters

• signal (DoubleValue) – value to monitor.

• upper_limit (DoubleValue) – maximum value of the settle range.

• lower_limit (DoubleValue) – minimum value of the settle range.

• settle_time (DoubleValue) – time, in seconds, signal must stay inside the settle range.

• timeout (DoubleValue) – seconds to wait before the function times out.

Returns

True: The signal failed to settle before the operation timed out. False: The signal settled before the operation timed out.

Return type

bool

This wait is non-blocking, so other tasks will run while this wait executes.

niveristand.library.ramp(ramp_out, init_value, final_value, duration)

Ramps a variable from an initial value to an ending value over the duration you specify.

Parameters

• ramp_out (DoubleValue) – variable you want to ramp.

• init_value (DoubleValue) – starting value.

• final_value (DoubleValue) – ending value.

• duration (DoubleValue) – time, in seconds, you want the ramp to take.

niveristand.library.sine_wave(wave_out, amplitude, freq, phase, bias, duration)

Plays a sine wave with the parameters you specify.

Parameters

• wave_out (DoubleValue) – variable onto which the sine wave plays.

• amplitude (DoubleValue) – amplitude of the sine wave.

• freq (DoubleValue) – frequency, in Hz, of the sine wave.

• phase (DoubleValue) – phase, in degrees, of the sine wave.

• bias (DoubleValue) – offset to add to the sine wave.

• duration (DoubleValue) – duration, in seconds, to play the sine wave.

niveristand.library.square_wave(wave_out, amplitude, freq, phase, bias, duty_cycle, duration)

Plays a square wave with the parameters you specify.

Parameters

• wave_out (DoubleValue) – variable onto which the square wave plays.

• amplitude (DoubleValue) – amplitude of the square wave.

• freq (DoubleValue) – frequency, in Hz, of the square wave.

• phase (DoubleValue) – phase, in degrees, of the square wave.

• bias (DoubleValue) – offset to add to the square wave.

• duty_cycle (DoubleValue) – percentage of time the square wave remains high versus low over one period.

• duration (DoubleValue) – time, in seconds, to play the square wave.

niveristand.library.triangle_wave(wave_out, amplitude, freq, phase, bias, duration)

Plays a triangle wave with the parameters you specify.

Parameters

• wave_out (DoubleValue) – variable onto which the triangle wave plays.

• amplitude (DoubleValue) – amplitude of the triangle wave.

• freq (DoubleValue) – frequency, in Hz, of the triangle wave.

• phase (DoubleValue) – phase, in degrees, of the triangle wave.

• bias (DoubleValue) – offset to add to the triangle wave.

• duration (DoubleValue) – duration, in seconds, to play the triangle wave.

niveristand.library.uniform_white_noise_wave(wave_out, amplitude, seed, duration)

Plays a uniform white noise wave with the parameters you specify.

Parameters

• wave_out (DoubleValue) – variable onto which the white noise wave plays.

• amplitude (DoubleValue) – amplitude of the white noise wave.

• seed (I32Value) – seed for random number generator.

• duration (DoubleValue) – duration, in seconds, to play the white noise wave.