
3 - 2 16
i
/18
i
/21
i
Startup Guide - May 2000 B-63003EN-2/01
3
Section 1 Overview
Before loading the ladder, here is a quick summary of machine control and the purpose of the ladder.
If you are already familiar with this, feel free to skip ahead to the next section.
Machine Control
The 16
i
/18
i
/21
i
machine tool control system consists of the control, motor(s), servo amplifiers, I/O,
and a machine tool and its operator interface (see Figure 3-1 below). The control unit itself is
comprised of two parts: the motion control and the machine control:
1
.
The motion control is responsible for generating motion commands signals and interpreting
the feedback signals as described in the previous chapter. This is known as the computer
numerical control (CNC). In addition, it provides the link between you and the control via
the LCD and MDI units. The CNC communicates with the other part of the 16
i
/18
i
/21
i
, the
machine control.
2
.
The machine control is a programmable logic controller (PLC) embedded within the
16
i
/18
i
/21
i
. It is referred to as a programmable machine control (PMC) within the
16
i
/18
i
/21
i
and it supports the interface between the CNC and the machine. For example,
the switches, buttons, and lights (start, stop, etc.) used to run or support the machine are all
managed by the machine control.
16
i
/18
i
/21
i
Machine
Control
Motion
Control
Machine
I/O
Machine
O
erator
Panel
Servo
m
lifier
LCD
MDI
PMC
CNC
Figure 3 - 1. 16
i
/18
i
/ 21
i
machine tool control system block diagram