Nothing much in the way of PID elements, just 100% reaction when one boundary is hit, 100% reaction when the other boundary is hit. Not much design, but common in cheap systems. Doesn't look like it's going to change anytime soon.
jb4 "There are two ways for you to have lower Prescription-drug costs. One is you could hire Rush Limbaugh's housekeeper ... or you can elect me President." John Kerry