Change Between General Devices And Latched (Battery Backed) Devices; How To Initialize Devices (Battery Backed) - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2.6.4

Change between general devices and latched (battery backed) devices

1. When using latched (battery backed) type devices as non-latch type devices
In FX /FX
3U 3UC
devices by the parameter settings.
Devices dedicated to latched type cannot be changed into non-latch type devices even by the parameter
settings. Such devices can be handled as non-latch type devices by clearing all latched (battery backed) type
devices by the initial pulse (M8002) in a program.
2. When using non-latch type devices as latched (battery backed) type devices
In FX /FX
3U 3UC
the parameter settings.
In FX PLCs, non-latched type devices can be changed to latched (battery backed) type devices when the
3G
optional battery is installed and the battery mode is selected in the parameter setting.
2.6.5

How to initialize devices (battery backed)

Latched type devices can be initialized by clearing the entire PLC memory using peripheral equipment,
clearing all latched memory using the special auxiliary relay M8032, or executing the ZRST instruction.
This subsection describes two major methods.
1. M8032 (latch memory all clear)
When M8032 is turned ON, all latched type devices
cleared.
M8032 can be turned ON and OFF using the forced ON/OFF operation from peripheral equipment or within
the sequence program. Note that latched type devices cannot be turned ON while M8032 is ON.
When turning ON M8032 within the sequence program, note that latched type devices are cleared during
END processing after M8032 is turned ON.
Program example: This program clears all latched type devices.
M8002
Initial pulse
*1. Includes general type devices in FX
type when the optional battery is installed.
2. ZRST (FNC 40) instruction (zone reset)
The ZRST instruction can clear multiple devices all at once.
(Because only a limited device range can be specified for the ZRST instruction, only a part of the latched type
devices can be cleared at a time.)
Program example: This program clears latched (battery backed) type devices in the ranges shown in the table
below in FX /FX
3U
Clear input
42
PLCs, some latched (battery backed) type devices can be changed into non-latch type
PLCs, non-latch type devices can be changed into latched (battery backed) type devices by
M8032
PLCs.
3UC
FNC 40
M500 M7679
ZRST
FNC 40
S500 S4095
ZRST
FNC 40
T246
ZRST
FNC 40
C100
ZRST
FNC 40
C220
ZRST
FNC 40
D200 D7999
ZRST
→ For details on the ZRST (FNC 40) instruction, refer to Section 12.1.
→ For details on latched type devices, refer to Subsection 2.6.2 and Chapter 4.
*1
(including reset coils of timers and counters) are
→ For details, refer to Subsection 37.2.11.
PLCs whose type is changed to the latched (battery backed)
3G
Auxiliary relay M500~M7679
State
T255
Timer
Counter
C199
Data register
C255
2 Overview (Sequence Program)
2.6 Program Memory and Devices
atched (battery backed) type
L
device range
S500~S4095
T246~T255
C100~C199,
C220~C255
D200~D7999