Simple PID Controller

python-pid_controller

def pid_controller(y, yc, h=1, Ti=1, Td=1, Kp=1, u0=0, e0=0)
	"""Calculate System Input using a PID Controller

	Arguments:
	y  .. Measured Output of the System
	yc .. Desired Output of the System
	h  .. Sampling Time
	Kp .. Controller Gain Constant
	Ti .. Controller Integration Constant
	Td .. Controller Derivation Constant
	u0 .. Initial state of the integrator
	e0 .. Initial error

	Make sure this function gets called every h seconds!
	"""
	
	# Step variable
	k = 0

	# Initialization
	ui_prev = u0
	e_prev = e0

	while 1:

		# Error between the desired and actual output
		e = yc - y

		# Integration Input
		ui = ui_prev + 1/Ti * h*e
		# Derivation Input
		ud = 1/Td * (e - e_prev)/h

		# Adjust previous values
		e_prev = e
		ui_prev = ui

		# Calculate input for the system
		u = Kp * (e + ui + ud)
		
		k += 1

		yield u

Lines 30 and 32, shouldn't it be:
ui = ui_prev + 1.0 / Ti * h * e
and
ud = 1.0 / Td * (e - e_prev) / float( h)

I changed the 1s to 1.0,and cast h to a float, otherwise I think this would produce incorrect results when your control constants, or sampling time are not 1.

If you're running python2 you'll need to make them floats as you have shown or add this import:
from __future__ import division

I don't think there are any changes required for Python 3.