Precautions For Use Of File Registers - Mitsubishi MELSEC Q Series Programming Manual

3.10

Precautions for Use of File Registers

This section explains the precautions for use of the file registers in the QCPU and LCPU.
(1) CPU modules that cannot use file registers
The Q00JCPU and Q00UJCPU cannot use the file registers. When using the file registers,
use the CPU module of other than the Q00JCPU and Q00UJCPU.
(2) Setting of file registers to be used
When using the file registers, the file registers to be used must be set with the PLC
parameter or QDRSET instruction. (The PLC parameters of the Q00CPU, Q01CPU and
LCPU need not be set since they are preset to "Use file register". QDRSET instructions are
not available with LCPU.) If the file registers to be used have not been set, normal operation
cannot be performed with the instructions that use the file registers.
Even when file registers to be used are not set in the PLC parameter, a program
that uses file registers can be created. For the CPU module other than the
Universal model QCPU and LCPU, an error does not occur when that program is
written to the CPU module.
However, note that the correct data cannot be written/read to/from the file register.
For the Universal model QCPU and LCPU, an error occurs if the program where
file registers are used is executed.
(3) Securing of file register area
(a) High Performance model QCPU, Process CPU, Redundant CPU, Universal model
QCPU
When using file registers, register the file registers to the standard RAM/memory card to
secure the file register area.
(b) Basic Model QCPU (except Q00JCPU)
The file register area has been secured in the standard RAM beforehand. The user
need not secure the file register area.
(c) LCPU
To use the file register, secure a file register area by registering the file register in
standard RAM.
The following table indicates the memories that can use the file registers in each CPU
module.
Memory
Standard RAM
Memory card *1 *2
*1: When the flash memory is used, only read from the file registers can be performed. (Write to the flash ROM
cannot be performed.)
*2: When the E
*3: Unusable for the Q00UCPU and Q01UCPU.
High Performance model QCPU
Process CPU
Redundant CPU
Universal model QCPU(except Q00UJCPU)
2 2
PROM is used, write to the E PROM can be performed with the PROMWR instruction.
*3
: Can be registered,
Basic Model QCPU
(except Q00JCPU),
LCPU
: Cannot be registered.
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