Mitsubishi Electronics FX3G User Manual

Page of 964
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FX
3S
/FX
3G
/FX
3GC
/FX
3U
/FX
3UC
 Series
Programming Manual - Basic & Applied Instruction Edition
2 Overview (Sequence Program)
2.5 Introduction of Devices Constructing PLC
1
Introdu
ction
2
Ov
ervi
ew
3
Instruction 
Li
st
4
D
evices 
in Det
ai
l
5
Specifi
ed the
De
vice
 &
 
C
onst
ant
6
Bef
ore
 
Pr
og
ra
mmi
ng
7
Bas
ic 
Instruction
8
FN
C00-FN
C0
9
Program Fl
ow
9
FNC
10-FN
C19
Mov
e & Com
pare
10
FNC
20-FNC
29
Arith. & Lo
gi
Operati
on
2.5.2
Device list
1. Input relays (X) and output relays (Y) 
→ Refer to Section 4.2.
• Input relay and output relay numbers are 
assigned to each main unit in octal "X000 to X007, 
X010 to X017 …, Y000 to Y007, Y010 to Y017 …"
The input relay (X) numbers and output relay (Y) 
numbers in extension units and extension blocks 
are also sequential numbers in octal respectively 
in the order of connection to the main unit.
• A digital filter is applied to the input filter of specific 
input relays, and the filter value can be changed 
by a program. Accordingly, for a purpose requiring 
high-speed receiving, assign such input relay 
numbers.
(Refer to explanation of filter adjustment, input 
interrupt, high-speed counter, various applied 
instructions, etc.)
2. Auxiliary relays (M)
→ Refer to Section 4.3.
• Relays built into the PLC are auxiliary relays, and 
are used for programs. Different from I/O relays, 
auxiliary relays cannot receive external inputs or 
directly drive external loads.
• There are latched (battery or EEPROM backed) 
type relays whose ON/OFF status is stored even if 
the PLC turns OFF.
3. State relays (S)
→ Refer to Section 4.4.
• State relays are used in the step ladder or as 
process numbers in the SFC expression.
• When a state relay is not used as a process 
number, it can be programmed as a general 
contact/coil in the same way as an auxiliary relay.
• State relays can be used as annunciators for 
external fault diagnosis.
4. Timers (T)
→ Refer to Section 4.5.
• A timer adds and counts clock pulses of 1, 10 or 
100 ms, and turns its output contact ON or OFF 
when the counted result reaches a specified set 
value.
A timer can count from 0.001 to 3276.7 seconds 
depending on the clock pulse.
• In  the  FX
3S
 PLC, 100 ms timers T32 to T62 are 
changed to 10 ms timers when the special 
auxiliary relay M8028 is driven in the program.
• The timers T192 to T199 are dedicated to 
subroutines and interrupt routines.
The timers T250 to T255 (T132 to T137 in FX
3S
 
PLC) are retentive type base clock timers for 100 
ms pulses. This means that the present value is 
retained even after the timer coil drive input turns 
OFF. And when the drive input turns ON again, a 
retentive type timer will continue its counting from 
where it left off.
5. Counters (C)
The following types of counters are provided, and
can be used in accordance with the purpose or
application.
1) For latched (battery or EEPROM backed) 
counters 
→ Refer to Section 4.6.
Counters are provided for internal signals of the
PLC, and their response speed is usually tens of
Hz or less.
- 16-bit counter: Provided for up-counting, 
counting range: 1 to 32767
- 32-bit counter: Provided for up-counting 
and down-counting, counting range: 
−2,147,483,648 to +2,147,483,647
2) For latched (battery or EEPROM backed) high-
speed counters
→ Refer to Section 4.7 or 4.8.
High-speed counters can execute counting at
several kHz regardless of operations in the PLC.
- 32-bit counter: Provided for up-counting 
and down-counting, counting range: 
−2,147,483,648 to +2,147,483,647 (1-
phase 1-counting, 1-phase 2-counting and 
2-phase 2-counting), assigned to specific 
input relays
6. Data registers (D)
→ Refer to Section 4.9.
Data registers store numeric data values.
All data registers in FX PLCs are 16-bit type (whose
most significant bit is positive or negative). When two
consecutive registers are combined, they can handle
32-bit numeric value (whose most significant bit is
positive or negative).
(For the numeric value range, refer to "Counter" on
the previous page.)
In the same way as other devices, data registers are
classified into general type and latched type (battery
or EEPROM backed).
7. Extension registers (R) and extension file 
registers (ER)
→ Refer to Section 4.10.
Extension registers (R) are the extended form of data
registers (D). They are protected by the battery
against power failure in FX
3U
/FX
3UC
 PLCs. 
In FX
3G
/FX
3GC
 PLCs, general type devices can be
protected against power failure when the optional
battery is connected. 
In FX
3G
/FX
3GC
/FX
3U
/FX
3UC
 PLCs, the contents of
extension registers (R) can be stored in extension file
registers (ER). 
In FX
3U
/FX
3UC
 PLCs, extension file registers (ER)
can only be used while a memory cassette is
mounted.