Ladder Logic - Programming language

Ladder Logic is a programming language created in 1994.

#731on PLDB

30Years Old

Ladder logic was originally a written method to document the design and construction of relay racks as used in manufacturing and process control. Each device in the relay rack would be represented by a symbol on the ladder diagram with connections between those devices shown. In addition, other items external to the relay rack such as pumps, heaters, and so forth would also be shown on the ladder diagram. Read more on Wikipedia...

Ladder Logic Wikipedia page
Ladder Logic first developed in International Electrotechnical Commission
Ladder Logic on HOPL
Ladder Logic appears in the TIOBE Index
See also: (3 related languages)SFC, BASIC, C

Example from Wikipedia:

+--------+
  --------------------+ A + B  +-----------
                      | into C |
                      +--------+
                         Adder