Question

What is the correct order of the development of the following?

1. Numerical control

2. Computer numerical control

3. Direct numerical control

4. Distributed numerical control

1. 1, 2, 3 and 4
2. 4, 2, 3 and 1
3. 1, 3, 2 and 4
4. 4, 3, 2 and 1

Answer 1

Correct Answer - Option 1 : 1, 2, 3 and 4

Explanation:

The earliest NC machines performed limited functions and movements controlled by punched tape or punch cards. As the technology evolved, the machines were equipped with increasingly powerful microprocessors (computers) with the addition of these computers, NC machines become CNC machines. After that Direct numeric control (DNC) also called distributed numerical control were evolved with the advancement of technology of working remotely.

Comparison of all the advancement in NC machine is done as:

NC	CNC denotes	DNC
NC stands for Numerical Control. It is defined as the machine which is controlled by the set of instructions in the form of numbers, letters, and symbols. The set of instructions is called a program.	CNC a computer numerical control that uses a dedicated microprocessor or computer to execute preprogrammed sequence machine control commands	Direct numerical control (DNC), also known as distributed numerical control, is a common manufacturing term for networking CNC machine tools. The program is done externally then sent to individual machines.
The remote control of the NC machine is not possible. In NC machine.	In CNC, remote controlling of operation is not possible.	DNC facilitates remote control.
Modification in the program is difficult. The programs in the NC machine cannot be stored.	CNC is an integral part of the machine.	DNC is not integral to machines; DNC computer can be located at a distance from machines
The accuracy is less as compared with the CNC.	CNC computer controls one NC machine. one NC machine as required.	Using DNC, the programmer can control more than one NC machines
The programs are fed into the punch cards. So correction in the machining sequence during operation is not possible	CNC software is to increase the capability of the particular machine tool.	DNC not only controls the equipment but also serves as a part of the management information system. The program is done externally then sent to individual machines.