278
7.2 Local Device
The local device is a device that can be used independently for each program. Using local devices allows
programming of multiple independently-executed programs without considering other programs. Note that local device
data can be stored in the standard RAM only.
If M7000 and higher portion is set as a local device, it can be separately used for each program that is executing
M7000 and higher portion.
The following devices can be used as local devices.
After program execution, data in the local device file of the standard RAM are exchanged with the data in the device
memory of the CPU module. For this reason, the scan time increases by the time for data exchange.
● There are some instructions for which a local device cannot be specified. For details, refer to the pages describing
devices available for each instruction in the following manual.
MELSEC-Q/L Programming Manual (Common Instruction)
● For the concept of the number of words used for the local devices, refer to Page 228, Section 5.2.
• Internal relay (M) • Counter (C) • Edge relay (V)
• Data register (D) • Timer (T, ST) • Index register (Z)
Ex.
Ex.
ON/OFF
M7000
ON/OFF
M7000
Program A
Program B
ON/OFF data of M7000
ON/OFF data of M7000
Standard RAM
For program A
For program B
Internal relay
Internal relay
Local device
Program A Program B Program C
Local device Local device
Restored
Saved
Restored
Saved
Restored
Program
For
program A
For
program B
For
program C
For
program A
For
program B
For
program C
For
program A
For
program B
For
program C