Plc Components Glossary - Mitsubishi Electric FX Series Training Manual

Appendix

PLC Components Glossary

A.5
The following table describes the meaning and functionality of the single components und parts
of a Mitsubishi PLC.
Component
Connection for
expansion
adapter boards
Connection for pro-
gramming units
EEPROM
Memory cassette slot
Extension bus
Analog
potentiometers
Service power supply
Digital inputs
Digital outputs
LEDs for indicating
the input status
LEDs for indicating
the output status
LEDs for indicating
the operating status
Memory battery
RUN/STOP switch
Training Manual GX IEC Developer
Description
Optional expansion adapter boards can be connected to this interface. A variety of differ-
ent adapters are available for all FX lines (except the FX
capabilities of the controllers with additional functions or communications interfaces. The
adapter boards are plugged directly into the slot.
This connection can be used for connecting the FX-20P-E hand-held programming unit or
an external PC or notebook with a programming software package (e.g. GX Developer).
Read/write memory in which the PLC program can be stored and read with the program-
ming software. This solid-state memory retains its contents without power, even in the
event of a power failure, and does not need a battery.
Slot for optional memory cassettes. Inserting a memory cassette disables the controller's
internal memory – the controller will then only execute the program stored in the cassette.
Both additional I/O expansion modules and special function modules that add additional
capabilities to the PLC system can be connected here. See Chapter 6 for an overview of
the available modules.
The analog potentiometers are used for setting analog setpoint values. The setting can be
polled by the PLC program and used for timers, pulse outputs and other functions.
The service power supply (not for FX
supply source for the input signals and the sensors. The capacity of this power supply
depends on the controller model (e.g. FX
through FX -32M„-„„: 250 mA, FX
2N
The digital inputs are used for inputting control signals from the connected switches, but-
tons or sensors. These inputs can read the values ON (power signal on) and OFF (no
power signal).
You can connect a variety of different actuators and other devices to these outputs,
depending on the nature of your application and the output type.
These LEDs show which inputs are currently connected to a power signal, i.e. a defined
voltage. When a signal is applied to an input the corresponding LED lights up, indicating
that the state of the input is ON.
These LEDs show the current ON/OFF states of the digital outputs. These outputs can
switch a variety of different voltages and currents depending on the model and output
type.
The LEDs RUN, POWER and ERROR show the current status of the controller. POWER
shows that the power is switched on, RUN lights up when the PLC program is being exe-
cuted and ERROR lights up when an error or malfunction is registered.
The battery protects the contents of the MELSEC PLC's volatile RAM memory in the
event of a power failure (FX
2N
timers, counters and relays. In addition to this it also provides power for the integrated
real-time clock when the PLC's power supply is switched off.
MELSEC PLCs have two operating modes, RUN and STOP.
The RUN/STOP switch allows you to switch between these two modes manually. In RUN
mode the PLC executes the program stored in its memory. In STOP mode program execu-
tion is stopped and it is possible to program the controller.
PLC Components Glossary
2NC
ans FX ) provides a regulated 24V DC power
2NC 3UC
, FX and FX
1S 1N 3G
-48M„-„„ through FX
2N
, FX2 and FX only). It protects the latched ranges for
NC 3U
). These adapters extend the
: 400mA; FX -16M„-„„
2N
-64M„-„„: 460 mA)
2N
A - 17