30
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
2 Overview (Sequence Program)
2.5 Introduction of Devices Constructing PLC
2.5
Introduction of Devices Constructing PLC
Many relays, timers, and counters are built into an FX
3U
/FX
3UC
PLC, with many NO (normally open) contacts
and NC (normally closed) contacts.
These contacts and coils are connected to make a sequence circuit.
A PLC is also equipped with data registers (D) and extension data registers (R) functioning as memory
devices to store numeric data values.
2.5.1
Relationship among devices
Arrows show transfer of signals.
4
1 2 3
Input terminal or
input connector
Input relay: X
Input relays function as receiving ports when the PLC receives signals from external
input switches.
The assigned device mnemonic is "X".
The PLC has built-in input relays in accordance with its scale.
Auxiliary relay: M
There are many
auxiliary relays
inside the PLC.
The assigned
device mnemonic
is "M".
State relay: S
There are many
state relays inside
the PLC.
The assigned
device mnemonic
is "S".
Timer: T
There are many
timers inside the
PLC.
The assigned
device mnemonic
is "T".
Counter: C
There are many
counters inside the
PLC.
The assigned
device mnemonic
is "C".
Output relay: Y
Output relays
function as ports
when the PLC
drives external
loads.
There are many
output relays inside
the PLC.
The assigned
device mnemonic
is "Y".
Output terminal
or output
connector
Contact for external output from output relay
(one NO contact)
The PLC has built-in output contacts in accordance with its
scale.
Содержание FX3U Series
Страница 1: ...PROGRAMMING MANUAL Basic Applied Instructions Edition FX3U FX3UC SERIES PROGRAMMABLE CONTROLLERS ...
Страница 2: ......
Страница 889: ......