DIN Rail
A DIN rail is a metal rail with a standard profile onto which devices inside a panel are clipped and fixed. The most common type is the 35 mm wide top-hat profile. Terminal blocks, relay sockets, power supplies and protection devices can be fitted and removed without tools.
What the rail provides is a mechanical standard: devices from different manufacturers sit on the same profile, line up at the same level and can be placed side by side. This makes the panel easier both to build and to extend later.
- Fixing: the rail must be screwed to the mounting plate at sufficiently close intervals; a long rail held at only a few points flexes under vibration and fatigues the device clips.
- End stop: end stops are fitted at both ends of the row of devices on the rail, otherwise the devices slide with vibration.
- Heat and clearance: leave space above and below devices that heat up so air can flow; do not pack drivers and power supplies on top of one another.
Rail mounting in panels on vehicles and work machines needs extra care: vibration here is continuous. Rather than leaving heavy devices on the rail clip, screw them directly to the plate, and carry light terminal and relay groups on the rail. Clamp the cable harness as soon as it enters the panel so that pulling force does not land on the terminal ends.
The context in which this term is used: Installation, redundancy and field continuity