Programming may be done in BASIC or machine code, but often programmable controller are designed to use relay ladder logic.
Relay ladder logic, as its name suggests, is based upon relay logic bodean expressions. Proprietary PCs each have their own set of instruction and programming manuals for individual PCs need to be consulted.
Just as a program written in BASIC has to be converted into machine code by special program called an interpreter, so relay ladder logic has to have an interpreter. Relay ladder logic is:
a.As hard to learn as machine code;
b.Slower than machine code in execution;
c.Much more limited than machine code or BASIC.
It is suggested therefore that any engineer coming new to the subject should choose systems using BASIC and machine code rather than relay ladder logic.
Vocabulary
1.albeit conj. 虽然
2.light-emitting diodes 发光二极管
3.relay ladder logic 继电器梯形逻辑图
4.archaically a.古体的；旧式的
5.retention n. 保留；保持
6.versed a. 熟练的；精通的
7.fluidics n. 射流
8.sheer a. 完全的；绝对的
9.profligate a. 浪费的
10.proprietary a. 专利的；专有的
11.bodean expression 布尔代数式
