Mitsubishi Electric FX3G SERIES Programming Manual page 728

Programmable controllers

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Table of Contents

Series Programmable Controllers

Programming Manual - Basic & Applied Instruction Edition

• Setting the WDT (FNC 07) instruction just before and after the INITR instruction as shown below:

If the processing time of the INITR command exceeds 200ms, set the watchdog timer value D8000 (unit: ms) to the

proceessing time or more.

2. Allowable number of writes to the memory

Note the following cautions on access to extension file registers.

• Data can be written to the memory cassette (flash memory) up to 10,000 times.

Every time the INITR (FNC292), RWER (FNC294) or INITER (FNC295) instruction is executed, it is counted as a

write to the memory. Make sure not to exceed the allowable number of writes.

When a continuous operation type instruction is used, data is written to the memory in every operation cycle of the

PLC. To prevent this, make sure to use a pulse operation type instruction.

• Execution of the LOADR (FNC290), SAVER (FNC291) or LOGR (FNC293) instruction is not counted as a write to

the memory. However, it is necessary to initialize the writing target sector before executing the SAVER (FNC291)

or LOGR (FNC293) instruction.

Every time the INITR (FNC292)or INITER (FNC295) instruction is executed, it is counted as a write to the memory.

Make sure not to exceed the allowable number of writes.

An operation error is caused in the following cases; The error flag M8067 turns ON, and the error code is stored in

• When any device number other than the head device number of a sector of extension file registers is set to

(error code: K6706)

• When a device number to be initialized exceeds "32767" (error code: K6706)

In this case, devices up to R32767 (ER32767) are initialized.

• When the protect switch of the memory cassette is set to ON (error code: K6770)

Program example

In the program example shown below, the extension registers R0 to R2047 in the sector 0 are initialized.

Note that the extension file registers ER0 to ER2047 are also initialized if a memory cassette is attached.

• Extension registers (R) [inside the built-in RAM]

Device number

Current value

Before execution

33 Extension File Register Control – FNC290 to FNC299

33.3 FNC292 – INITR / Initialize R and ER

The watchdog timer is reset.

After execution

Fx3u series Fx3uc series