14 - 2

MELSEC-Q
14 DEDICATED INSTRUCTIONS
14.1 List of dedicated instructions

The dedicated instructions explained in this Chapter are listed in Table 14.1.

Table 14.1 List of dedicated instructions

Application Dedicated
instruction Outline of functions Reference
ABRST1
ABRST2
ABRST3
Absolute position restoration
ABRST4
This function restores the absolute position of the designated
axis of the QD75. Section 14.3
PSTRT1
PSTRT2
PSTRT3
Positioning start
PSTRT4
This function starts the positioning control of the designated
axis of the QD75. Section 14.4
TEACH1
TEACH2
TEACH3
Teaching
TEACH4
This function carries out teaching the designated axis of the
QD75. Section 14.5
Writing to flash ROM PFWRT This function writes the buffer memory parameters,
positioning data and block start data to the flash ROM. Section 14.6
Parameter initialization PINIT This function initializes the buffer memory and flash ROM
setting data to the factory-set data (initial values). Section 14.7
14.2 Interlock during dedicated instruction is executed

The absolute position restoration instruc tion (ABRST ), positioning start instruction

(PSTRT ) and teaching instruction (TEACH ) cannot be executed

simultaneously in each axis. If they are executed at the same time, the secon d and

later instructions are ignored by an internal interlock (no error will occur).

The timing of the positioning start dedicated instruction (PSTRT ) is as shown below.

PSTRT instruction ON
Interlock provided by PLC CPU
BUSY (XC to XF)
Positioning completed (X14 to X17)
OFF
OFF
OFF
OFF
ON
ON
ON
ON