6 DATA COMMUNICATION USING THE NON PROCEDURE PROTOCOL MELSEC-Q

6.1.6 Received data count and receive complete code settings

The following default values have been set for the received data count and receive complete code that are used for data reception with the non procedure protocol.

If it is necessary to change the following default settings, change the settings on the GX Configurator-SC "Non procedure system setting" screen according to the specifications of the external device (see Sections 8.4.5 and 8.4.7).

Setting data

Default

Allowable range

Buffer memory address where

Remarks

value

the setting value is stored

 

 

 

Received data

511 (1FFH)

Less than the size of the

A4H/144H

Unit is in accordance with the

count

 

receive data storage area

 

word/byte units designation

Receive

0D0AH

0000H to 00FFH

 

When any code is set

 

A5H/145H

When there is no receive

complete code

(CR, LF)

FFFFH

 

complete code

 

 

 

 

REMARK

Other than through the setting using GX Configurator-SC or the TO instruction at the startup of the Q series C24, the received data count and receive complete code setting values can be changed even after data communication has started if the timing is as shown in the chart below.

The following describes the procedure for changing setting values for data reception via the non procedure protocol after the start of data communication, and for the resumption of data reception processing. Specifically, the module restrictions are explained, along with the timing and procedure for changing the setting values.

(1) Data receiving method

Reception using a dedicated instruction (INPUT) or an interrupt program (1) cannot be performed. (Transmission using a dedicated instruction (OUTPUT) can be performed.) Data must be received using the FROM instruction in the main program. The following describes the I/O signals. (A program example is shown on the following page.)

1 For details on the data reception using interrupt programs, see the User's Manual (Application).

 

I/O signal

Signal name

Device that turns ON/OFF

 

 

Timing

 

CH1 side

CH2 side

CPU

Q series C24

 

 

 

 

 

 

 

 

 

 

 

 

X3

XA

Reception data read request

 

 

 

 

 

 

(Only when normal)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reception

X4

XB

Reception abnormal detection

 

 

 

 

 

 

(Only when abnormal)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Y1

Y8

Reception data read completion

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

POINT

When the reception abnormal detection signal (X4/XB) turns ON, read the error code from the buffer memory below, and then check the type of error and take corrective action based on the information found in Chapter 10.

• Data reception result storage area (addresses 258H/268H)

6 - 20

6 - 20