9 DEDICATED INSTRUCTIONS

MELSEC-Q

9 DEDICATED INSTRUCTIONS

Dedicated instructions are used to simplify programming when using intelligent function module functions.

This chapter describes the dedicated instructions for the Q series C24, which is part of the functions of the QCPU (in Q mode) explained in this manual.

9.1 Dedicated Instruction List

The following table lists the dedicated instructions explained in this chapter.

Application

Dedicated

Description of function

Explanation

instruction

page

 

 

On-demand function transmission

ONDEMAND

Sends data using the on-demand function of the MC

Section 9.2

 

 

protocol.

 

Non procedure protocol

OUTPUT

Sends data for the specified data count.

Section 9.3

communication

INPUT

Reads received data.

Section 9.4

Bidirectional protocol

BIDOUT

Sends data for the designated data count.

Section 9.5

communication

BIDIN

Reads received data.

Section 9.6

Communication status confirmation

SPBUSY

Reads the status of data transmission/reception via a

Section 9.7

dedicated instruction.

 

 

 

 

 

Perform the receive data clear without stopping the

 

Receive data clear

CSET

transmission processing during the non procedure

Section 9.8

 

 

protocol.

 

POINT

(1)The user should not change data values (control data, request data, etc.) designated by a dedicated instruction until the execution of the dedicated instruction is completed.

(2)Dedicated instructions for the Q series C24 are executed based on the current setting values stored in the buffer memory when the module is started.

When it is necessary to change a setting value, change the value by GX Configurator-SC before starting up the module.

Alternatively, a setting value can be changed via the sequence program using

a CSET instruction before starting up the PLC CPU (See the User's Manual

 

 

(Application)).

9

1)

Area of buffer memory assigned as applicable functions for dedicated

 

 

 

instructions.

 

2)

Setting values for data communication

 

 

• Word/byte units designation

 

 

• Receive complete code

 

 

• Received data count

 

 

etc.

 

9 - 1

9 - 1