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.