Function that generates steps time series from user given values
Your type checks are distracting, they are probably better extracted to a separate function.

def check_type_or_raise(obj, expected_type, obj_name):
    if not isinstance(obj, expected_type):
        raise TypeError(
            "'{}' must be {}, not {}".format(
                obj_name,
                expected_type.__name,
                obj.__class__.__name__)


Note that this has slightly different behaviour than your code: you would e.g. accept a step_width of 2.5 and convert it to a 2. This is typically not what you want, so I think it is better to raise for such cases.

If you don't mind the conversion, then you probably don't need to wrap your calls to int() in a try and re-raise, as you will already get a nice error, e.g.:

&gt;&gt;&gt; int('abc')
ValueError: invalid literal for int() with base 10: 'abc'


I would also refactor your code to have the output creation happen in a single, common place, after some manipulation of the arguments:

def steps(step_width, values, repeat=1, size=None):
    check_type_or_raise(step_width, int, 'step_width')
    check_type_or_raise(repeat, int, 'repeat')
    values = np.asarray(values)
    if size is not None:
        check_type_or_raise(size, int, 'size')
        # This does rounded up integer division without floating point
        repeat = (size - 1) // (len(values) * step_width) + 1
    return np.tile(np.repeat(values, step_width), repeat)[:size]