|This article is about an older version of DF.
A pressure plate is made from one mechanism and works somewhat like a lever, acting as a trigger for one or more systems that have been linked to it. However, instead of being deliberately tasked to be toggled by the player (and then pulled by the first dwarf to respond to fill that job), they're activated by hostile creatures stepping on them.
Pressure plates can be linked to all the same objects levers can. The effects (and any delays associated with them) are listed in the Lever article.
Pressure plates default to toggleable, where they send an On signal when a creature steps upon them and send an Off signal when it's released. Note that while a pressure plate will send its "On" signal the instant it is triggered, it will not send its "off" signal until it has been in the untriggered state for 100 steps[Verify].
Some toggleable trap designs may prove useless when there are a large amount of invaders walking back and forth over the pressure plate, as there will not be enough time for it to activate before it is switched again.
Pressing in the "Add new task" menu will change them to one-use mode, where upon being activated, they do their work then deconstruct themselves, destroying their mechanisms in the process; thus, it is a bad idea to use masterwork mechanisms in one-time pressure plates.